Wu Zunyou, chief epidemiologist at the Chinese Center for Disease
Control and Prevention, and Zeng Guang, a senior researcher at the
Chinese Center for Disease Control and Prevention, answer questions
about the new COVID-19 cases reported in Beijing Why is Xinfadi wholesale market suspected to be the source of the latest COVID-19 outbreak in Beijing? Wu: Normally, the lower the temperature, the longer virus can
survive. In such wholesale markets, seafood is stored frozen, enabling
the virus to survive for a long time, resulting in increased chances of
its transmission to people. Additionally, a large number of people enter
and exit such places, and a single person entering with the coronavirus
can cause the spread of the virus in these places. As all the confirmed
cases in this outbreak are found to be linked with the market,
attention was given to the market. What is the source of transmission of the virus in the
market? Is it people, foodstuffs such as meat, fish or other things sold
in the market? Wu: It is very difficult to conclude the exact source of the
transmission. We cannot conclude that the salmon sold in the market is
the source just based on the finding that cutting boards for salmon in
the market tested positive for the virus. There may be other
possibilities such as that one owner of a cutting board was infected, or
other food sold by an owner of a cutting board tainted it. Or a buyer
from other cities caused the virus' spread in the market. The flow of
people in the market was big, and many things were sold. It is not
likely the exact source of transmission will be found in a short time. Before the outbreak, Beijing had reported no new locally transmitted
COVID-19 cases for more than 50 days, and the coronavirus should not
have originated in the market. If it is confirmed after investigation
that none of the new cases of people who tested positive for the virus
got infected in Beijing, then it is likely that the virus was introduced
into Beijing from overseas or other places in China via tainted goods. How big is the risk of further spread of the virus in Beijing? Wu: Right now, the key task for COVID-19 control and prevention in
Beijing is to identify the source of transmission and find all close
contacts of confirmed cases to prevent further spread of the virus.
Beijing has been responding very quickly this time, and I have full
confidence in epidemic control in Beijing. Arduous efforts are needed to reduce risks of further spread of the
virus, including dispatching a large number of professionals to search
for close contacts of confirmed patients and conducting lab analysis on
the virus samples as quickly as possible. Based on the known information, the rebound of the outbreak has been
largely limited to areas surrounding Xinfadi market, and the virus has
not spread to the whole area of Beijing and threatened its total
population of more than 20 million. What should Beijing residents pay particular attention to in light of the epidemic control situation? Wu: There is no need for the public to panic, as we have accumulated
rich experience in COVID-19 epidemic control and treatment of patients. The city authority has published the movement path of all the
confirmed patients, so residents who find they have been to affected
places can pay more attention to their health condition and receive
nucleic acid tests if necessary. For other residents, it is still
necessary to maintain good habits such as wearing masks in places that
lack ventilation and frequently washing their hands. Is it necessary to conduct nucleic acid tests for coronavirus on the whole population of Beijing? Zeng: No. But expanded testing is required to cover places including
stores in residential compounds where goods from Xinfadi wholesale
market are sold, and other residential compounds and restaurants linked
with Xinfadi in the city. Please feel free to contact us by sending your questions to
question@chinadaily.com.cn or commenting on China Daily app. We will ask
experts to answer them.
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