What Chinese Doctors Learned About the Prevention and Detection of COVID-19 from Their Experience in WuhanBelow is an interview with Wang Zhou, MD by Salon.com. Dr. Wang is one of the authors of the Handbook of Prevention and Control of COVID-19, published in China on their experience dealing with COVID-19. The introduction to the interview explains that frontline doctors in China assembled a comprehensive guide of what they observed about COVID-19 in Wuhan.
The Center for Medical Language Service of Guangdong University of Foreign Languages was nominated for this mission of translation and recruited volunteers. "The information in the Handbook -- especially the measures that individuals and communities can adopt at the time of an outbreak -- might serve as an important source of information on the prevention and control of both present and future epidemics. Even if China's experiences do not apply to all countries in the same manner, they should serve as valuable references," the introduction says. Is Everyone Equally Susceptible to COVID-19?The novel coronavirus is newly emergent in humans. Therefore, the general population is susceptible because they lack immunity against it. 2019-nCoV can infect individuals with normal or compromised immunity. The amount of exposure to the virus also determines whether you get infected or not. If you are exposed to a large amount of virus, you may get sick even if your immune function is normal. For people with poor immune function, such as the elderly, pregnant women or people with liver or kidney dysfunction, the disease progresses relatively quickly and the symptoms are more severe. The dominant factor determining whether one gets infected or not is the chance of exposure. So, it cannot be simply concluded that better immunity will lower one's risk of being infected. Children have fewer chances of exposure and thus a lower probability of infection. However, at the same exposure, senior people, people with chronic diseases or compromised immunity are more likely to get infected. What Are the Epidemiological Characteristics of COVID-19?The emergent epidemic of COVID-19 has experienced three stages: local outbreak, community communication, and widespread stage (epidemic). Transmission dynamics: in the early stage of the epidemic, the average incubation period was 5.2 days; the doubling time of the epidemic was 7.4 days, i.e., the number of people infected doubled every 7.4 days; the average continuous interval (the average interval time of transmission from one person to another) was 7.5 days; the basic regeneration index (R0) was estimated to be 2.2 to 3.8, meaning that each patient infects 2.2 to 3.8 people on average. As for the main average intervals -- for mild cases, the average interval from onset to the initial hospital visit was 5.8 days, and that from onset to hospitalization 12.5 days; for severe cases, the average interval from onset to hospitalization was 7 days and that from onset to diagnosis 8 days; for fatality cases, the average interval from onset to diagnosis was significantly longer (9 days), and that from onset to death was 9.5 days. The COVID-19 epidemic passed three stages of communication: 1) the stage of local outbreak (cases of this stage are mostly related to the exposure of a seafood market); 2) the stage of community communication (interpersonal communication and clustering transmission in communities and families); 3) widespread stage (rapid spread, with large population flow, to the entire country of China and even the world.) What Are the Routes of Transmission of 2019-nCoVAt present, it is believed that transmission through respiratory droplets and contacts is the main routes, but there is a risk of fecal-oral transmission. Aerosol transmission, mother to child transmission and other rutes are not confirmed yet. Respiratory droplet transmission is the main mode of direct contact transmission. The virus is transmitted through the droplets generated when patients are coughing, sneezing or talking, and susceptible persons may get infected after inhalation of the droplets. The virus can be transmitted through indirect contacts with an infected person. The droplets containing the virus are deposited on the surface of the object, which may be touched by the hand. The virus from the contaminated hand may get passed to the mucosa (or mucosae) of oral cavity, nose and eyes of the person and lead to infection. The live novel coronavirus has been detected from feces of confirmed patients, suggesting the possibility of fecal-oral transmission. When the droplets are suspended in the air and lose water, pathogens left behind to form the core of the droplets (i.e. aerosols). Aerosols can fly to a distance, causing long-distance transmission. This mode of transmission is called aerosol transmission. There is no evidence that the novel coronavirus can be transmitted through aerosol yet. A child of the mother with COVID-19 was confirmed to have positive throat swabs after 30 hours of birth. This suggests that the novel coronavirus may cause neonatal infection through mother to child transmission, but more scientific research is in need to confirm this route. How Resilient Are Coronaviruses in Different Environments?Viruses generally can survive for several hours
on smooth surfaces. If the temperature and
humidity permit, they can survive for several
days. The novel coronavirus is sensitive to
ultraviolet rays and heat. Sustained heat at
132.8° F for 30 minutes, 75% alcohol,
chlorine-containing disinfectants, peracetic
acid, chloroform, and other lipid solvents can
effectively inactivate the virus. Chlorhexidine
(also known as chlorhexidine gluconate) also
efectively inactivates the virus. The survival time of the novel coronavirus at different environmental temperatures is as follows:  2019-nCoV is a coronavirus that underwent genetic mutations. The incubation period of the virus is as short as 1 day but generally considered to be no longer than 14 days. But it should be noted that some reported cases had an incubation period of up to 24 days.
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In
the early days of the novel coronavirus outbreak,
Chinese officials shared their understanding of
the novel coronavirus with the world through the
World Health Organization. Tested and tempered by
other viral epidemics (such as SARS), the
frontline professionals at the epicenter -- Wuhan
-- decided to share their invaluable experiences
and lessons drawn from the current outbreak as
well as during their careers in China and various
countries in the form of the Coronavirus
Prevention Handbook, originally published in
Chinese.
