Joint China-WHO Press Conference of WHO-Convened Global Study of
Origins of SARS-Cov-2
Ladies and gentlemen, dear friends, good
afternoon. Welcome to the joint China-WHO press conference of
WHO-convened Global Study of Origins of
SARS-Cov-2: China part. This is Mi Feng, the spokesperson of China
National Health Commission.
Since COVID-19 became a global pandemic, WHO has been actively
promoting the international cooperation in terms of the COVID-19
response. China has always been showing firm
support to WHO in terms of unleashing the role of WHO in the leadership
of the global COVID-19 response.
With the consensus based on negotiation between two sides, China and
WHO have conducted joint research of the SARS-CoV-2 global origin
tracing: China part. Since the arrival of
international expert teams in Wuhan on January 14th 2021, the joint
expert team has been working as three groups, respectively the group of
epidemiology, molecular epidemiology and
bioinformatics, animal and environment. The experts have been working
in the forms of video conferences, on-site interviews and visits and
data analysis, as well as discussions. They have
conducted systematic and full-fledged research. The joint expert team
have already concluded the China part of scientific research related to
the origin tracing in Wuhan according to the
During this period, MR. Ma Xiaowei, the Minister of National Health
Commission has been discussing and having extensive communication with
Doctor Tedros, the Director General of
WHO through telephone. They thoroughly exchanged ideas in terms of the
scientific cooperation on the origin tracing.
For today's conference, we have guest participants on the podium
with us from the joint expert team and they are Mr. Peter Ben Embarek,
food safety expert from WHO, and Madam
Marion Koopmans, member of the joint expert team and also team leader
of the molecular epidemiology group. And also professor Liang Wannian
from Tsinghua University. He is the
team leader of the Chinese side of the joint expert team.
They will present the work that the joint expert team has done and
introduce the public and the press to the updates and highlights of
SARS-CoV-2 origin tracing of this joint study and
also they are going to answer your questions. Consecutive
interpretation will be offered in today's press conference. So
journalists can ask question either in Chinese or in English.
First I would like to invite professor Liang Wannian, the team
leader from the Chinese side to introduce relevant information of this
joint study of origin tracing in Wuhan.
Dear friends from the press, good afternoon. On behalf of the team
leader from the Chinese side of the China-WHO joint expert team of the
SARS-CoV-2 origin tracing research, I
would like to give you a brief introduction of the major research
process and also the key findings of our endeavor in our recent joint
study. With regards to the conclusions and future
recommendations, these two parts will be introduced by the team leader
from the WHO expert team, Doctor Peter Ben Embarek.
This joint research is the China part of the WHO-convened Global
Study of Orgins of SARS-CoV-2. The joint research report is based on
the relevant research, a crystallization from
the Chinese and international scientists in the past. And the
literature review of the previous research and the analysis will be
also included in this joint report.
In May 2020, the 73rd World Health Assembly requested the Director
General of the World Health Organization to work with the partners to
identify zoonotic source of the causative
virus of COVID-19, and the route of its introduction to the human
population, including the possible role of the intermediate hosts. The
aim was to prevent reinfection with the virus in
animals and humans and prevent the establishment of a new zoonotic
reservoir, as well as to reduce further risk of emergence and
transmission of zoonotic diseases.
In July 2020, WHO and China began the ground work for the studies to
identify the virus origins. The agreed terms of references or ToRs
defined the scope of the studies, the main
guiding principles and the main expected deliverables. These ToRs
define an initial phase of short-term studies to better understand how
the virus might have been introduced and started to
circulate in Wuhan. The WHO Secretariat and the Chinese government have
jointly set up an international multidisciplinary team to design,
support and conduct these studies to contribute
to the tracing of the origins of SARS-CoV-2 and the route of its
transmission to human beings. The work of the joint international team
was set it as the ground for origin tracing work in
other parts of the world.
Therefore, the global origin tracing work will not be bound to any
location and may evolve geographically as increasing amount of evidence
is generated and science-based hypotheses
keep evolving. The overall results and findings will help to improve
global preparedness and effective response to SARS-CoV-2 and emerging
zoonotic diseases of similar origins.
The joint international team comprises 17 Chinese experts and 17
international experts from ten other countries. And they represent WHO,
World Organization of Animal Health,
partners in the Global Outbreak Alert and Response Network (GOARN). The
joint study team carries out a research over a 28-day period from
January 14th to February 10th 2021 in
The joint expert team, through its three working groups, reviewed
and discussed together the progress made by Chinese experts in phase
one studies in the following three areas:
epidemiology, animals and environment, molecular epidemiology and
In addition to the three working groups, the joint international
team received detailed presentations on relevant topics to help inform
its work, and undertook a series of site visits and
interviews with key informants.
Now I would like to give you a brief introduction of the key
findings of our joint study. The first part of my introduction will be
the result of the molecular epidemiology study.
As most of the emerging viruses have their origins in animals, in
order to gather more insights of the process of virus spill-over and
global spread, it is necessary to understand the
diversity and evolution of viruses in an animal reservoir, the
interactions between animals, environment and humans, and relevant
factors contributing to the efficient human-to-human
Generally speaking, a virus causing global pandemic must be highly
adaptive to human environment. Such adaptation may occur unexpectedly
or may have evolved through multiple
steps with each step driven by natural selection.
Consequently, the research for the origins of SARS-CoV-2 therefore
needs to focus on two phases. The first phase involves viral
circulation in animal hosts prior to zoonotic transfer.
During this evolutionary process, various animal species may serve as
Progenitor strain of SARS-CoV-2 may have acquired an enhanced
ability to infect humans during their circulation. The discovery of
viral sequences with high homology to
SARS-CoV-2 suggests that SARS-CoV-2 may have originated from zoonotic
transmission, but the reservoir hosts remain to be identified.
The second phase involves evolution of SARS-CoV-2 during its spread
in human populations, following zoonotic transmission. The likelihood
of animal-human spill-over increases with
increased frequency and intensity of animal and human contact.
Spill-overs may be occurring repeatedly, if the genomic of the virus in
the reservoir requires further adaptation to efficient
onward transmission. Such early spill-overs may go undetected. Once
viruses with pandemic potential evolve or spill over, which would
enable their spread, it results in substantial clusters
of viruses with adaptive mutation in different geographical human
populations, and hence causing the pandemic of COVID-19.
Evidence from surveys and targeted studies so far have shown that
coronavirus most highly related to SARS-CoV-2 are found in bats and
pangolins, suggesting these mammals may be
the reservoir of the virus that causes COVID-19, due to the high
similarity in genetic sequences between the sample virus and
SARS-CoV-2. However, the viruses identified so far from
neither of these two species are sufficiently similar to SARS-CoV-2 to
serve as direct progenitor of the SARS-CoV-2.
Apart from these findings, the high susceptibility of minks and cats
to SARS-CoV-2 suggest that there may be additional species of animals,
for example those belonging to mustelidae
or felidae family as well as other species, as potential reservoir.
Comparison of the data from sequence databases with those from surveys
of potential reservoir species shows that these
possible reservoirs are massively under-sampled and the research in
this area is not sufficient.
The joint team reviewed data collected through China National Center
for Bioinformation in their integrated database, containing all the
available coronavirus sequences and meta
For the cases detected in Wuhan, China, by linking the sequence data
and epidemiological background, cases with illness onset before
December 31st , 2019 were selected for in-depth
analysis. The final analysis showed that several of the cases selected
with exposure history to Huanan market had identical virus genomes,
suggesting these several cases may be part of a
However, the sequence data also showed that some diversity of virus
was already present in the early phase of the pandemic in Wuhan,
suggesting the possibility of unsampled chains of
transmission outside the Huanan market cluster. There was no obvious
cluster of cases by the epidemiological parameters of raw meat exposure
or exposure to fur animals.
Finally, according to the relevant literature review on the data of
early circulation of SARS-CoV-2 from published studies, these studies
from different countries suggest that
SARS-CoV-2 circulation was possibly several weeks earlier than the
initial detection of cases. Some of the suspected positive samples were
detected even earlier than the first case reported
in Wuhan. This indicates the possibility of the missed diagnosis of
cases in the early circulation in other regions.
These kinds of missed diagnosis and diseases are highly related to
the features of SARS-CoV-2. This is a basic judgment that we can make
after the review and analysis of the global
data from global research community.
The second part of my introduction would be the origin tracing work
conducted by epidemiological group. Surveillance of influenza-like
illness or ILI and Severe Acute Respiratory
Illness, SARI, with appropriate laboratory confirmation, is a standard
measure of the impact of influenza and other respiratory viruses in the
community to determine the possible impact of
morbidity or the causative agent of COVID-19 in the month before the
outbreak of COVID-19. Adult sentinel surveillance data from ILI from
one hospital in Wuhan and SARI surveillance
data from one hospital in Hubei province was reviewed. The full name of
SARI is Severe Acute Respiratory Illness. The finding indicated that
there was no substantial unrecognized
circulation of SARS-CoV-2 in Wuhan during the latter part of 2019.
Origin tracing of stored lab samples. In retrospective testing of
stored samples of more than 4,500 research project samples from the
second half of 2019 stored at various hospitals in
Wuhan, the rest of Hubei province and other provinces, no SARS-CoV-2
Analysis of retail pharmacy for the purchase of the antipyretics,
cold and cough medications have also been conducted. It did not provide
a useful indicator of early community
And also, we have conducted review of the surveillance data on all
cause mortality and pneumonia-specific mortality during the period from
July to December 2019 in Wuhan city and
the rest of Hubei province. There was no evidence of substantial
unexpected fluctuation in mortality that might suggest the occurrence
of the transmission of the SARS-CoV-2.
There is no indication of the transmission of the SARS-CoV-2 in the
population in the period before December 2019. There is not enough
evidence either to determine whether
SARS-CoV-2 infection had spread in Wuhan before December 2019.
We have also conducted research among 233 health institutions in
Wuhan by searching the records of more than 70,000 cases presenting one
of the four conditions or symptoms,
including fever, acute respiratory illness, influenza-like illness or
unspecified pneumonia in the period from October 1st to December 10th,
We have reviewed the testing of the blood obtained from the relevant
data bank, and also tested the antibodies in the blood samples. All
were negative. And it was also followed by the
multidisciplinary clinical review and screening of those cases, which
determined that none were compatible with SARS-CoV-2 infection.
Retrospective search for potential earlier cases in Wuhan in the
two-month period prior to the outbreak detection in December 2019 has
not revealed clear evidence of the occurrence of
the clinical cases of the SARS-CoV-2 infection. Based on analysis of
this and other surveillance data, it is considered unlikely that any
substantial transmission of SARS-CoV-2 infection
was occurring in Wuhan during those two months.
It is not possible to determine how the SARS-CoV-2 was introduced
into the Huanan market or other markets on the basis of the current
epidemiological information. There was a
possibility of transmission of SARS-CoV-2 infection among the
population of Wuhan in December 2019.
Although there was an association with the Huanan Seafood Market in
some of the early cases, others were associated with other markets, and
the other cases had no market's
association at all. It is likely that an outbreak occurred at Huanan
Seafood Market. But there are also transmission appearing to have the
occurrence elsewhere in Wuhan at the same time.
This is our basic judgment. It is not possible to determine how
SARS-CoV-2 was introduced into the Huanan Market based on the current
The third part of my introduction will be the research of the animal
and environment group, the third group of our joint study.
Coronaviruses that are genetically related to SARS-CoV-2
have been identified in different animals, including horseshoe bats and
pangolins. Sampling of bats in Hubei province, however, has failed to
identify evidence of SARS-CoV-2 related
viruses, and sampling of wildlife in different places in China has so
far failed to identify the presence of SARS-CoV-2.
Environmental sampling in Huanan market from the point of its
closing revealed widespread contamination of surfaces with SARS-CoV-2,
compatible with possible introduction
pathways of the virus through infected people or contaminated
cold-chain products, animals and animal products.
According to this research, the testing results of all the animal
related samples from Huanan market were negative. The cold-chain
products have not been tested yet.
SARS-CoV-2 can survive in conditions found in frozen food, packages
and cold-chain products. Recent outbreaks in China have been linked to
the cold chain. Studies have shown that
the virus can survive for a long time, not only at low temperatures,
but also at refrigerator temperature, indicating that it can be carried
long distance on cold chain products. More attention
should, therefore, be paid to further research of the virus in terms of
its persistence in the low temperature environment and also in the damp
environment where the humidity is relatively
In Huanan market, a substantial number of stores sold cold-chain
products. But it is unclear so far how well the first confirmed cases
in Huanan Market can be corresponded to the
stores that sold these products or not. We need further research in
This is my introduction of our major findings of the three groups of the joint study.
Thank you, professor Liang Wannian. Now I would like to invite Doctor Peter to give an introduction.
Thank you, Mr. Mi Feng and Professor Wannian for the introduction
and for presenting our findings and also how we have conducted our work.
I'm here this afternoon with Prof. Marion Koopmans from the
department of Virology of the College of Medicine of Erasmus University
in the Netherlands. And she's one of the
member of the international team that came here a month ago together
with colleagues from WHO and OIE. We have the presence of Marion, but
it is unfortunate we cannot invite all the
members of the joint team on the podium together. We will answer your
questions later on together.
I would like to start by thanking you who are here in the room today
and those joining us remotely. We have followed many of you in the past
few weeks. I would also like to thank
those who we have seen every day following us on cold days for long
hours in the rain and bad weather, and we really thank you for
following us. It has provided us with constant
reminding of the importance of this work and focus that the world is
putting on this work. So thank you for following us.
And the international team would like to recognize the impact of
epidemic on the city of Wuhan from the individuals affected, the
communities affected, both from the government
officials, the citizens, the scientists and the health workers in
particular who fought the disease last year here, in particular. Thank
for the engagement of my colleague Professor Wannian,
who spent several months here last year on the front line. Thank you
So you have heard the many findings that we have detected out of our
studies and work in the past few weeks and they will be detailed in the
report of this mission that would be
released later on. I would like to concentrate on some of our key
conclusions from these findings. We came here with two goals, two
objectives. One was to try to get a better understanding
of what happened at the beginning of the event in December 2019. This
was the starting point for our work, but also the starting point of the
initial outbreak. We've focused on trying to
understand what happened during that period and trying to see if that
period had a previous history, could we move the history of the start
of the outbreak further down the line in earlier
weeks of 2019. And then in parallel, we also embarked on trying to
understand how it happened, how did the virus emerge and at some point,
jumped and was introduced in the human
population. So these were two broad objectives we had and all our
studies and work and discussion and visits were trying to get better
understanding of these two pictures.
So in terms of understanding what happened in the early days in
December 2019, did we change dramatically the picture we had
beforehand? I don't think so. Did we improve our
understanding? Did we add details to that story? Absolutely. You heard
some of the key findings from Professor Wannian on this picture.
In trying to understand the picture of December 2019, we embarked on
the very detailed, profound search for all the cases that may have been
missed, cases early on in 2019. And you
heard the detail from Professor Wannian. The conclusion was that we did
not find evidence of large outbreaks that could be related to cases of
COVID-19 prior to December 19 in Wuhan
We can also agree that we have found evidence of why the circulation
of the virus was in December. It was not just only the cluster outbreak
in the Huanan market, but the virus was
also circulated outside of the market.
The picture we see is a very classical picture of the start of an
emerging outbreak where we start with a few sporadic cases early on in
the month of December. And then we start to see
small outbreaks where the disease starts to spread in clusters and we
have seen it further that was happening in the Huanan market.
And these early clusters are usually and also in this case, the way
one detects the first cases, the first sign of these emerging disease
and that's what happened during the month of
When mapping all the initial cases of the time throughout December,
combining that with location and mapping of some of them in the market,
in different parts of the market, and
combining that with genetic sequence and genetic information from some
of these cases, we could see that a picture becoming more and more
clear of the spread within the market and
spread outside the market. Initially there were very few cases and then
more and more cases as we moved into January 2020.
And the data and information we got from the very large amount of
looking retrospectively to different studies of mortality data, of
surveillance disease data, etc., and re-analyzing a
large number of the initial genetic sequences identified in the early
days of the events and early January, all these data fit perfectly and
very well, confirming us in the picture I just
Then we embarked on trying to better understand how the virus was introduced in Wuhan, the way it came from.
All the work that has been done on the virus and trying to identify
its origin continue to point towards a natural reservoir of this virus
and similar viruses in bat population.
But since Wuhan is not a city or an environment close to these bat
environments and direct jump from bats to the city of Wuhan is not very
likely. Therefore, we have tried to find
what other animal species were introduced and moving in and out of the
city that could have potentially introduced or contributed to
introducing the virus, in particular, in the Huanan
The market was dealing primarily with the frozen product, in
particular frozen animal product and maybe seafood. But they were also
windows selling products from domestic agents --
wildlife, farmed fur animals and their products.
So the joint team in their studies have identified the vendors who
were trading this type of products, identified the suppliers of these
vendors, identified the farms from where these
products were coming from, and they were coming from different parts of
the country and some of the products were also imported products, of
course. So there is the potential to continue
to follow this lead and further look at the supply chain and animals
that were supplied to the market in the frozen and order process.
There was also a large amount of testing for the coronavirus
responsible for COVID-19 in many different animal species throughout
the country in large number of samples of both the
domestic animals, farmed animals, wild animals in many different
provinces. To these studies, it has not been possible to point any
animal species as a potential reservoir for this disease.
They indicate that currently and also back in 2019, it doesn't look
like there was wide circulation of the virus in any animal species in
The search for the possible route of introduction of the virus to
different animal species and the specific reservoir are still under
working progress. What we did after looking at our
findings and combining the information that we could extract from this
finding and we then sit down and say to ourselves -- okay, the next
step is, let's look at the future. What are these
conclusions telling us and how are we going to move forward in our
search for the start of the story? Look at all the possible pathways
for the introduction of the virus into the human
population. You will have the details in the report, but it's basically
a very simple illustration of different pathways coming from wild
animals into different environments where human and
animals and products can interact.
Out of that exercise, we then identified four main hypotheses or
group of hypotheses on how the virus could have been introduced in the
human population. We decided to take that
approach to really cover all the possible pathways, initially without
any value and without any assessment or a judgment, but purely to make
sure that we would cover all the possible
pathways for the introduction of the virus in the human population.
Once we identified these four key hypotheses, we also did a
literature research to make sure that we would not have missed some
valuable options that others could have come up with.
Then we sat down and went to these different hypotheses, one by one,
and assessed their likelihood by putting forward arguments for and
arguments against such hypotheses. And then
assessing the likelihood of each of them in a systematic way, in a
rational way, using scientific arguments and combining all the
information that we had collectively collected in the past
four weeks, and also using an extensive search of the literature for
useful scientific arguments.
So the four main hypotheses that we evaluated, identified and
re-evaluated are first, a direct zoonotic spill-over that is a direct
transmission from an animal reservoir or animal species
into the human population. So a direct jump from an animal to a human.
The second hypothesis was through the introduction of the virus,
through an intermediary host species, meaning another animal species
potentially closer to humans, where the virus can
potentially adapt, and then circulate and then jump to humans.
The third one was the food chain, in particular, meaning the
potential for food, frozen products in particular, acting as the
surface for the transmission of the virus into the human
population and all the food-related route of transmission.
The last one was the possibility of a laboratory-related incident.
As I have said, we took a systematic approach to look at all these
hypotheses, putting arguments for and against, and assessing the
likelihood using the standardized set of parameters.
Each of them was then used to help us plan in a useful direction to
help us continue our way forward into a better understanding of the
Our initial findings suggest that the introduction to an
intermediary host species is the most likely pathway and one that we
require more studies and more specific targeted research.
Similarly and connected to this hypothesis is also including the
possibility of transmission through the trade of frozen cold-chain
Then we were making the difference between the introduction of the
virus into the human population and the possibility of the circulation
of the virus through long distance and through
different settings, or the introduction of the virus into a particular
city, like a market, for example.
Then the hypothesis of a direct spill-over from an original animal
source into the human population is also a possible pathway and is also
generating recommendation for future
However, the findings suggest that the laboratory incident
hypothesis is extremely unlikely, and to explain the introduction of
the virus into the human population. Therefore, it is not a
hypothesis that implies to suggest future studies into our work, to
support our future work into the understanding of the origin of the
So the discussion on the different hypotheses and how they will help
us direct our future studies was extremely helpful. We have been able
to then develop a series of recommendations
for future studies, future work in line with the plan we had outlined
last July in terms of reference for how we would go about understanding
the origin of the virus and what type of
sequence in the studies that would be needed, was developed. The plan
we developed in July 2020 is still valid, has been extremely helpful in
the guiding our work. The recommendations
we are making at the end of this mission are in line with that approach.
So we have identified and we're proposing our report a large number
of valuable recommendations and ideas for future studies. But here I
would just mention some of the key studies
and key recommendations we are making.
One of them is to expand existing integrated data basis that connect
epidemiological, clinical and molecular data on cases, in particular,
and extremely useful as well, genetic sequences.
So all that information can be possible and connected through
integrated databases, and that should be done at the global level to
facilitate the analysis and connection of data coming from
a different part of the world in helping us understanding better and
connecting better all the data and information that comes from many of
these research projects.
And that will also include data from animal surveys, from
environmental surveys and enable us to integrate all these information
and make the best use of many of our studies.
In our search of still trying to identify earlier cases, because
that will help us better understand the start of the event, we would
recommend to continue some of the good work that has
been initiated in looking for material that can be analyzed, that is
still available from that time. A lot of this material has been already
looked at and we heard that many studies that have
been conducted for the past weeks and months. We have identified
potential, new sources of valuable material that could be analyzed and
help us perhaps move forward in that direction.
One of them, just to give an example, is blood samples from blood banks
and not only here in Wuhan and all the cities and provinces of interest
but also use that material else where there
are initial reports and indication that perhaps the virus was also
present in individuals, in other places and other countries. And that
kind of study would help get a better picture of the
initial days of the event potentially if some of them turn back
positive. So we have to continue our search for material that can be
analyzed and give us clues on what happened in the early
days of the event.
We should also explore new approaches and new ways of exploring and
reinforcing the use of serological tests in some of the material that
have already been tested. Here we're talking
about tests that allow us to look in old sample for traces of the
presence of the virus at that time. And there we need new approaches
and new ways of doing that.
And of course, we can continue exploring the potential that early
cases have. Even if memory fades, if people are less present and
accessible and if clinical material is also less and less
available,there is still value we had targeted in the studies of some
of these cases can potentially yield more useful information. But a lot
has already been done in trying to extract all the
information that we could extract from these early cases in December
And for the studies to better explore the hypothesis that an
intermediary animal species or an original animal species was involved
in the introduction, here we need to conduct more
surveys into certain animal species that could be the reservoir or act
as a reservoir and of course including more sampling and more studies
of bat population, not only in China because
already a lot has been tested in terms of bats in China, but we know
that some of the similar species found in China are also found in
neighboring countries in the sub-region and in other
parts of the world. And there is under-surveyed because not much has
been done in many of these countries in terms of surveying bats. But
there we may have some interesting studies as
We also have to do much more into understanding the possible role of
the cold-chain frozen products in the introduction of the virus and
over a distance. We know that the virus can
persist and survive on conditions that are found in these frozen
environments. But we don't really understand if the virus can then
transmit to human and on which conditions this could
happen. It will be interesting to explore if frozen wild animal that
was infected could be a potential vehicle for the introduction of the
virus or the viruses into market environments, where
we know that the temperature, the humidity, the environment could be
conducive to a rapid spread of the virus in such environment. So a lot
of work needs to be done to better understand
this interesting pathways.
We should also look further back in tracing the source of the
products and the source of the animal products in particular that were
in Huanan market in December 19, and go back and
see if we can find products that were produced at that time and that
are still available to also look at the suppliers to these vendors in
the market, and see if we can go further back in terms
of identify interesting clues in the farming environment in the species
being raised in these farms and where they were potentially coming from
before that. This is another area worth
What was important for us when we developed our hypotheses was to
make sure that they were not geographically bound because since the
beginning we have taken an open approach
in terms of not limiting ourselves in this manner. One of the clear
reason is that the possible paths from whatever original animal
species, all the way through the Huanan market could have
taken a very long and convoluted path, involving also movements across
borders, travels, etc., before arriving in the Huanan market.
Therefore, it's also very interesting to follow up on
every one of these clues and preliminary reports and indications that
perhaps here and there in other places in the world. There were
individuals who were infected and try to follow up on
these and connect again dots, connect the different pieces of
information to try to get a better understanding of this whole picture
and again, just following all the leads, following the
science, following well-designed and conducted studies.
Apologize for these two lengthy introductions, but we feel it was
necessary to present you with a clear picture of all the work that we
have conducted in the past four weeks before and
trying to give you a picture of all our findings and conclusions. And I
would now give the floor back to Doctor Mi Feng. Thank you.
Thank you, Dr. Peter. Just now we have listened to the introduction
from the team leaders from both sides. They have been introducing the
major content and highlights of the joint
report. Now we would like to take your questions. Before you raise your
question, please introduce yourself by telling us which news agency
you're with. In order to provide more chances
to different journalists, one question from one journalist, please.
Thank you. Now we are glad to take your question.
Hello, there. My name is Josh, reporter with Thompson Reuters in
Shanghai. I'd like to see if we drill down with a bit more specificity
about the likelihood for these hypotheses that
were presented. So whether it is possible for each of the three of us
actually give a percentage of the likelihood to which we think that the
virus either originated from wildlife and
subsequently transmitted to a human or through some form of frozen food.
Peter over to you. Thank you.
Thank you. And I will ask Marion to try to give you an answer.
Yes, thank you very much. So this is a very tough question. What we
really did is to develop the figure that was shown to help structure
our thinking, but be systematic about it. What
that does is it lists from literature, from studies, various evidence
for or against and various uncertainty. And that is what we then have
used to assess what we think is more or less likely. I
think going into exact percentages is really overstating what can be
done. It's really developed to help us structure our thinking, also
structure the discussions somewhat, because these are
very complex questions and there are many different potential routes
that you can think of. That's the key use of it. So we've gone as far
as broad categories, most likely, less likely. And
that's how I think for the time being, we will use this. What we also
discussed is that whenever new information becomes available and that
could be any time, because there's ongoing
studies in different parts of the world, we can take this again and say
with this new information, does our assessment of these different
And maybe in our complete report, we will list all elements that
were used in the assessment, including the literature, the studies, all
the aspects that we included to make that
I would like to invite Professor Liang Wannian to offer additional comment.
I applaud the view offered by Dr. Marion. Actually, there will be
more detailed introduction of the methodology and more abundant
evidence that are going to be demonstrated in the
full joint report and also in the future recommendations and
suggestions for the research orientations. Actually one of the deepest
impressions for me is that as regards for the question you
are asking, it requires a lot of daunting and demanding efforts. We
have tried our best to provide an evaluation of the possible hypothesis
and also other kinds of the possibilities in a
scientific way by unleashing the joint wisdom from the experts of the
two sides based on the existing available evidence. This is a teamwork.
And also we have not using the only
quantitative nor only qualitative method either, as it was introduced
by Dr. Marion. And we were using the semi-quantitative method to
conduct the relevant research. We have stratification
of five levels and to match each evaluation of different kinds of the
possibility, to put them into different matrix to have a comprehensive
consideration and evaluation.
I'm with CGTN. I have one question related to Huanan seafood market.
Is the Huanan seafood market the source of the COVID-19 epidemic in
Wuhan? What are the possible infection
sources of the cases related to Huanan seafood market? How was the
virus introduced to Huanan seafood market? What are possible early
transmission routes and what kind of role did
Huanan market play in the early stage of epidemic in Wuhan? Thank you.
Dr. Peter over to you.
Thank you for some very well thoughts and detailed questions. These
are exactly the same questions we have ourselves, so you should join us
next time on the team. We don't know the
exact role of the Huanan market. We know that there was spread among
people who were and lived and worked and visited the Huanan market
throughout December. How it was
introduced and spread within the market is still unknown. We have a map
and we have mapped over time the spread of the virus, among the earlier
cases we were linked to the market. So
we have a picture of where the cases were, for example, in the market.
We have also genetic sequences for some of these cases that we can use
to help us to understand this picture. And all
that tells us that there was a spread among people in the Huanan market
in December. And therefore, the market probably was a setting where
that kind of spread could happen easily. But
it's not the whole story and we know that there was also spread among
individuals who were not linked to this market. They were linked to
other markets. There had no links to market. So
the picture is not clear in that respect. And for the introduction
part, it's part of the discussion we are having and the work we are
planning ahead of us through this hypothesis, evaluation is
to understand how it was introduced. And as of today, we are still
working with the hypothesis that it could have been introduced by a
person who was infected and then spread it to other
persons in the market. And that could be one of the traders. It could
be a visitor, but it could also be through the introduction of a
product. As I mentioned, among the more interesting
products where frozen farmed wild animals and some of these species are
known species susceptible to this kind of viruses. So these are
providing clues and providing direction for the next
round of studies. We have a lot of good material now to further explore
many of these avenues and hopefully some of them will provide us with a
good direction afterwards.
In terms of time and place, what we know is that some of the first
cases that could be linked to the market, where detected symptoms in
the first two weeks of December. And that
indicated that they were probably infected around the start of December
or late November. But we can't go into more details with the
information we have looked at and that we have
studied in detail. Thank you.
Any additional comment from Professor Liang?
I would like to offer additional comment. First, according to the
current research progress of this joint research team, Huanan Market
may not be the first place of the outbreak. It may
not be the place that witnessed the earliest case, either, as it was
also introduced by Dr. Peter. The onset date of the earliest case in
this joint research was December the 8th, 2019 and also
the onset date of the earliest confirmed case that had association to
the Huanan seafood market was December the 12th. And actually,
according to our research from the epidemiological
group, the case with the onset date on December the 8th actually have
no relationship or association either with Huanan seafood market. The
second point I would like to explain is that
why have we attached so much importance to Huanan Market in terms of
the considering whether Huanan Market is one of the earliest places of
the outbreak or even the source of the
outbreak? Because at the beginning, we have very limited knowledge
concerning the properties and features and the etiology of the virus
and the disease as well. We noted that this kind of
pneumonia-like disease actually could occur on the cluster base. So
that is why we focused our early research in Huanan Market and relevant
cases that have association with Huanan
seafood market for the earlier cases with the suspected pneumonia or
PUE, Pneumonia of Unknown Etiology. And actually, in the research of
those early cases, a large number or a high
proportion of those early cases had association or have market exposure
history with Huanan seafood market. But later, when there have been
enhanced and improved testing capacity and
also with the improvement and development with different kinds of the
testing tools or test kits, we have greatly increased our understanding
of the virus. So when we conducted the
retrospective study related to the early cases, in the earlier
confirmed cases, some of those earlier confirmed cases actually did not
have any market exposure history with Huanan seafood
market. It was also mentioned by Dr. Peter previously and actually we
have also conducted relevant research of the possible introduction of
the virus transmission of the Huanan seafood
market from several possible introduction pathways either directly from
animal to any intermediary hosts or from the cold-chain transmission or
introduction. So we are having full
exploration of this kind of possible introduction pathways. This will
be also a highlight of the future research.
Next question, please.
I am Tom Cheshire, Sky News. Of the four hypotheses, the one you
decisively rejected was the laboratory incident. Can you explain the
evidence of the reasoning for discarding that
Dr. Peter, thank you.
Thank you. We evaluated this hypothesis in the same way we evaluated
the other hypotheses described by Marion. We looked at what are the
arguments for and against such a
hypothesis. So in short, you can see in the report the more detailed
evaluation of these hypotheses, but in short, it's about yes, accidents
do happens. Unfortunately, we have many examples
from many countries in the world of the past accidents. So this is not
impossible. It happens once in a while. We also in terms of arguments
against, look at the fact that nowhere previously
was this particular virus researched or identified or known. There has
been no publication, no reports of this virus or another virus
extremely linked or closed to this, being worked with in
any other laboratory in the world. We were also discussing with the
managers and the staff of many of the relevant laboratories in the
region and looking and discussing with them these
hypotheses as well, and hearing from them how their staff health
monitoring program, how their audits program, for example, are
conducted and what this revealed in the past months and
years. We also looked, for example, at the Wuhan Institute of Virology,
P4 level laboratory and the states of that laboratory. And it was very
unlikely that anything could escape from such
a place. And we also know that when lab accidents happened, they are
extremely rare. If you look at the history of lab accidents, these are
extremely rare events. So this is not the first
thing that happened on or would happen on a regular basis. So many of
these evaluations and the arguments were put for and against and helped
us take a rational approach to assessing the
likelihood of such an event happening. As I said, we looked both at the
arguments against but also the arguments for to make sure that we are
not biased in our approach. And again, in
terms of arguments for the fact that, as I said, past accidents have
happened all over the world. There was the fact that some of the
laboratories were in the city of Wuhan and all these
arguments were put for and against each other in helping us making this
For us, it was important to develop a system to evaluate all these
hypotheses where we could take a rational approach and look at fact and
evidence in a rational way and try to move
away from the situation that has been around for the past year where
all of us and many people around the world have all come up with. There
are personal views and feelings, wanted to
move away from "I think it is this way" or "I believe it is this way".
And try to move away from that and put rational facts on the table that
everybody can then look in a systematic way.
We felt that was a much more useful approach than to put personal
views, feelings, etc., are looking at only half of the arguments. Thank
I agreed with the answer offered by Dr. Peter. The hypothesis of lab
leak is put into the matrix of extremely unlikely as a conclusion of
the research outcome of the joint team. On the
basis of a serious discussion and very diligent research, we have
reached the extremely unlikely conclusion. As regards for the
hypothesis of lab leak, there are two possible pathways if
there was one. First, virus was engineered by humans, but this
hypothesis has already been refuted and rejected by the whole
scientific community around the world. Second, there may be a
leak of the virus from the lab. But in terms of the leaking of the
virus, it should be leaking of existing or known virus. However, in all
the laboratories in Wuhan, there is no existing virus
of SARS-CoV-2. If this virus does not exist, there would be no way that
this virus could be leaked. In addition, for all the laboratories in
Wuhan, including WIV, they uphold a very
stringent and high quality management system. And also proceeding from
the current evidence, we regard the lab leak hypothesis is extremely
unlikely. Thank you.
Mi Meng: Next question, please.
From Hubei Radio Network. The number of the confirmed patients has
already been cleaned to zero in Wuhan 9 months ago. In terms of the
origin tracing in Wuhan, how do the joint
expert team members conduct this kind of origin tracing, including the
identification of the early cases?
Maybe I can start. What was done was a series of studies. So there
were reports of known cases from later December. There was a series of
studies to try and find if there was evidence
for earlier circulation. That was done by a systematic analysis that is
in the report of different registrations. One is a registration that
lists the number of people with fever with respiratory
symptoms in a wider region that was looked at to see if there was
evidence for earlier increase in the number of people with flu-like
symptoms, for instance, that was seen in December, but
not before that.
The same was done looking at mortality statistics. And we've seen in
other countries that correlates very well with activity of SARS-CoV-2.
So that again showed increase, a peak that
said there was considerable circulation in December, second half of
December, but not really much before that.
The third element was a very extensive review of patients and
patient records by clinical teams from, I think, 233 health care
centers in Wuhan. They have with their knowledge of now
what COVID-19 cases look like, have looked back in their records to see
if they found evidence for earlier cases. That is what has been done.
What all the studies then showed was there
was a number of recorded cases in December with the first people that
were mentioned by Professor Liang. That's how that was done. We cannot
say there was absolutely no circulation
and there were no cases before December because that's not what you can
do by this approach. But what we can say is there's no evidence for
widespread circulation much earlier. That's
what the studies conclude.
Additional introduction of the methodology that we have been adopted
in this joint research. And actually, in our joint research, it covers
three methodologies. First, we conduct ample
and abundant retrospective study. And second, by reviewing the
accumulated or existing information or material, we tried to generate
literature review and also to have some relevant
analysis in a comprehensive manner of those existing material or
information. The third methodology is that we tried to connect the dots
by analyzing different associated element in a
holistic manner by pricing in as many factors as we can in a highly
integrated and systematic manner. So in our research, our diverse and
multi-prong approaches can allow us to have
different kinds of comparative studies and also to better draw
inferences from those causal relationship. So apart from those kinds of
broad-spectrum analysis, we also provide description of
the current situation. This kind of all-encompassing research
methodology can allow us to reach a more comprehensive conclusion
portfolio. Thank you.
We are already having two and half hours together in this press conference. Due to the interest of time, last question, please.
Thank you, from the Wall Street Journal. I was wondering if you
could talk a little more about the animals that were found alive or
dead at the Huanan Market. For example, I don't
think it has ever been confirmed what exactly those animals were. And
you mentioned that some are known to carry coronaviruses. Have you
identified some of greater interest to you as
potential intermediate hosts? Have you identified ones that maybe were
in the market earlier, but it had left by the time that inspectors
arrived, by the time the market was closed? And in
terms of following the trial and trying to identify the traders and the
farms and the sources of those animals, could you go into a bit more
detail about how far you've got and what's the
stumbling block? What needs to be done next?
And then a quick follow-up on the Wuhan Institute of Virology. You
mentioned that there were no coronaviruses in Wuhan that matched
SARS-CoV-2, but did you obtain that you ask
for and obtain information, data, samples regarding any gain of
function experiments that might have been done at Wuhan Institute of
Virology, which might be working with one type of
coronavirus and then enhancing it through some genetic mutation. Thank
Thank you, I will let Marion start with the first part of the question. Thank you.
The question about animals. I think first, it is important to
emphasize that the testing did not reveal any positives, but the full
trace-back that was done was very extensive. Trace-back
of all animals and other products on the market showed that there were
some animal species that have been confirmed as susceptible, like
rabbits, or that could be suspected to be
susceptible, like ferret badger, bamboo rats. The way that is
interpreted is to really say if they were there, then maybe they could
have been similar animals earlier. So it is an entry point
for a trace-back research because that's the step that we're now
looking for. We have a deeper understanding of the early situation --
where would you go for a next step of these origin
studies. The reason why that raise some interest is also that some of
the trace-back was in farms or in traders in regions that are known to
harbor bats with a closely-related viruses. So it is
really seen as an entry point for rational, for taking the next step of
surveys in animals, on farms. That's how we've looked at.
Then I will take the second part of your question about the Wuhan
Institute of Virology. We went there and we have also received the
visits of some of the staff here. They have
participated in further discussion and worked with us. We've had over
the weeks quite substantial interaction with the staff there. During
the visit, we first had the visit of the place, the
institute, the different laboratories. And then a very long frank open
discussion with the management and the staff of the institute. First,
they gave us a description, very detailed description
of their research, both present and past, all the projects involving
the studies with bats and coronaviruses and so on, and also some of the
more advanced projects. And then we engaged in
the discussion with them on the different lab-related hypotheses,
because they have been on the front line of the discussion around this
hypothesis for the past year. And it was very
interesting to hear directly from them how they are thinking in terms
of how can we explain this one, how can we dismiss this one, are we
using the wrong arguments, are we providing the
wrong evidence or are we answering questions in the wrong way. So we
had a very interesting discussion on their views, on all these
hypotheses involving their lab. And we discussed how
to improve that communication, how to provide the right arguments in
the future for better explaining their position, explaining their
views. And of course, they are the best one to be able
to dismiss any of these claims and provide answers to all the questions
that are out there around it. So we also feel that by again taking our
detailed and rational approach, we will help to
better clarify some of these claims around specific studies, gain of
functional working with samples directly from bats, etc. You will also
have in the report the minutes of our different
visits and meetings with different individuals and this one will also
be in the report. Thank you.
I would like to cite a few numbers for joint animal research study.
First and foremost, we have conducted testing of the serum samples,
numbering 11,000 from different species of
animals like pig, cow, goat, chicken, duck and goose as a kind of
testing sampling from the livestock and poultry from 31 provinces in
China from 2019 to 2020. And the testing results of
those 11,000 samples of SARS-CoV-2 antibody were all negative. We have
also done the testing related to the 12,000 swap samples and animal
tissue samples from different kinds of
animals in terms of PCR testing. The testing results were all negative
as well. In addition, from 2019 to 2020, we have conducted PCR testing
for 26,800 samples generated from different
kinds of animals that are distributed in 24 provinces in China. Again,
the PCR testing results were all negative.
Meanwhile, as regards for the testing of the samples from wild
animals, the samples collected during the period from November 2019 to
March of 2020 were taken. We have conducted
testing of 1,914 serum samples from 35 different species of wild
animals. The testing results of antibody testing from the serum samples
were all negative. And also before and after the
COVID-19 outbreak, we have increased our sampling scale from Huanan
seafood market, Wuhan municipality and other cities in Hubei province
and also the neighboring provinces of
Hubei, and collected 50,000 samples of the wild animals covering 300
different species. With the PCR testing of those more than 50,000
samples, the testing results were again negative
again. Thank you.
Dr. Peter expressed that he would like to take one more question.
Thank you. I'm from AFP. I'd like to ask. So the Chinese government
and the Chinese media have highlighted various reports of virus cases
in countries such as Italy and other places
abroad that appeared in late 2019 with the implication that the virus
originated from overseas. How likely do you think this is and do you
think there's a possibility that they were passed on
to the sort of seemingly unrelated places across the world from
undetected mild cases traveled to Wuhan? Do you think that because
there's obviously substantial spreading we had at the
time with several concurrent clusters, in addition to Huanan Market.
Sorry. Would you please repeat your question?
Sure. Okay, so I'd like to ask, so the Chinese government and
Chinese media have drawn attention to reports of several virus cases
that appeared in other countries outside of China
such as Italy in late 2019 with the implication that this virus
originated from overseas. How likely do you think this is? Especially
given that there were several clusters in Wuhan in
December 2019 at the same time? Do you think it's likely that maybe a
mild or asymmetric case traveled from Wuhan to these places in
different places around the world that might have
led to the clusters elsewhere?
What we have done is looking into that question also again in a
systematic manner. So the focus here initially was on what exactly can
we learn about the initial phase of the pandemic
in Wuhan. That showed that there was clearly circulation in December.
But as part of that work, we also reviewed what is available in the
literature and also in the databases about viruses
possibly circulating elsewhere. And that has found a couple of, a few
publications that would suggest that, for instance, in Italy, there had
been already circulation in December, may be late
November, but difficult to know. Because the methods for that were not
confirmatory. So they did not provide full evidence for that
circulation, but these parts of information is part of
what we collected, reviewed and included in our recommendations for the
next step. So in the next step, what we say is we should really go and
search for evidence for earlier circulation,
wherever that is indicated, and indications like this can come from
that kind of literature. So this is therefore in our recommendations
for follow-up. Maybe to then say, could that mean that
the virus had traveled from Wuhan to elsewhere? Again, here we take a
step-wise approach. But looking at what evidence is there, what
evidence could be found, it would be possible to get
genetic information and then see what that tells us.
This is a very good question and also your question has explained
the issue by itself -- why do we need to take an international
perspective in terms of the origin tracing of
SARS-CoV-2. That is also why we will need to have the joint endeavor
from the international scientists to have this kind of research in a
highly cohesive manner to identify the possible
pathways and to identify the possible rationale behind. That is also an
orientation that both from the joint research team and also different
scientists around the world will try to follow in
their future plans. Thank you.
Any final comment from Dr. Peter?
Thank you. Thank you all for all your very interesting questions. As
you heard, many of them are exactly the same questions we asked
ourselves over the past few weeks. And just to
let you know that we have answered some of your question today, but the
other members are not here and will be available for questions in the
coming days and we will also organize more
media access in the coming days for you and your colleagues. As we go
back home, we will also have opportunities back afterwards in a few
And as I said, you're only facing three of us here, but we have been
over the past four weeks and even before working closely with some 30
to 40 colleagues who were part of the joint
team. And over the past few weeks, we have really had an intense and
very productive work among that very special group. I would like to
thank them all individually for all their
contribution and efforts.
And beyond them, we were discussing that earlier today, there are
probably more than 1,000 individuals who have contributed over the past
four weeks in providing us with data,
helping us analyze data, generating reports, and finding and helping us
getting information and processing them. And it's also here an
opportunity for us to thank them all for that. So as
you can hear, it's a huge, huge group and amount of work that is behind
the outcome of this joint-study and robust and very numerous details
that came out of this work.
And to go back to the work itself in my closing remark, I would like
to point the detail that marked me, because before embarking on this
work like probably many of you, I was
thinking how will it be to actually be on the ground and trying to find
answers around the first cases. And who are they? What information
could they provide about the origin of the virus?
It was in a way fascinating to realize that these people are not
holding very exciting clues when we talk to one of the first cases who
had symptoms in early December. When you talked to
one of these cases, you immediately think they must have some very
special habits, hiking in the mountains, having special wild pets at
home. All these kinds of ideas pop up. And then
you realize that they're very much like all of us, no special
particular history of interest, spending most of their days on the
internet or doing the same activities and sports and jobs of his
work, type of jobs as many of us do. So it's also illustrating how
complicated this work is and therefore it's not that easy to come up
with all the answers after a few weeks of studies.
Therefore, we have to understand that these are complex studies that
need to be done systematically. And that's how we bit by bit can
connect the dots and get all the information and we
need to move forward. And that's the approach we have taken. That's
approach we will continue to take in continuing this work together with
our colleagues in China and in the
international team. So again, thank you to my colleagues and thank you
to my friend Liang.
I would like to express my appreciation to the three experts on the
podium with us. COVID-19 global pandemic has been exerting
unprecedented and profound impact to the whole
human society and the future progress of the development of the global
community. However, people from different countries never change their
pursuit for the betterment of their life. As
it was mentioned by Director General, Dr. Tedros of WHO, there will
always be the light at the end of the tunnel. As long as we unite as
one, we will achieve the ultimate victory. Chinese
New Year, the year of ox, is coming soon. Here I would like to wish all
of you happy Chinese New Year, good health and all the best.
That's the end of the press conference. Thank you.