6 local time, the Proceedings of the National Academy of Sciences (PNAS) published an academic paper, “The implications of the implicit transmission of the new coronary pneumonia outbreak response to the enlightenment ” (The implications of the silent for the control of the control of COVID-19 outbreaks). The study found that the spread of the new coronavirus is mainly caused by latent and asymptomatic infections. The study was carried out by scientists from the University of York in Canada, Yale University in the United States, the University of Maryland School of Medicine and other institutions.
The spread of the new crown virus is mostly hidden.
At present, one of the key ways to control the spread of the virus is to isolate patients with symptoms, but a large number of asymptomatic and latent infections cannot be ignored, the article said. By modeling, the researchers found that the spread of the new coronavirus, mostly in the process, is a recessive transmission, which is caused by the latent and asymptomatic infections.
According to the “New Coronary Virus Asymptomatic Infection Management Code” issued by the State Council’s joint prevention and control mechanism, asymptomatic infected people have two situations: First, after 14 days of isolation medical observation, there are no self-perceived or clinically recognizable symptoms and signs;
Professor Jennifer Wright of New York University Langone Medical Center says the “incubation period” refers to the period of time when an asymptomatic infected person has not shown symptoms. Previous studies have confirmed that patients in the incubation period of neo-coronary pneumonia are the most contagious, which is not common in respiratory diseases. Photo credit: Forbes
The article said that under the outbreak, many places increased socio-economic pressure, the public demand for the liberalization of anti-epidemic measures are growing. For the government, full yaware of the risk of hidden transmission is critical to the development of follow-up epidemic prevention policies. The proportion, infectiousness, and duration of asymptomatic infections all have an impact on the effectiveness of the epidemic.
In order to control the outbreak, at least one-third of the hidden vectors need to be identified and isolated
Previous studies have found that about 17.9% to 30.8% of all infected people did not show symptoms. The study calculated the corresponding scale of recessive transmission based on the proportion of asymptomatic patients in different situations.
Assuming that 17.9 per cent of cases in the outbreak did not show symptoms, in which case transmission caused by an infection in the incubation period could account for 48 per cent of transmission and asymptomatic infection resulting in transmission of 3.4 per cent of the spread. Assuming that 30.8 per cent of cases in the outbreak did not show symptoms, in which case transmission caused by an infected person during the incubation period could account for 47 per cent of transmission and asymptomatic infection to 6.6 per cent of transmission.
In summary, the study believes that even if people with symptoms are immediately quarantined, the outbreak cannot be fully controlled, and subsequent large-scale outbreaks are still possible.
The study found that if the risk rate was to remain below 1%, at least one-third of the hidden infections must be identified and isolated, the study found.
The authors argue that the results of the study suggest that the government needs to expand testing to screen asymptomatic suspected cases, and that for confirmed cases, their exposure history needs to be tracked as soon as possible to identify patients in the incubation period.
The authors say that because asymptomatic infections are difficult to track down, and with various omissions that may occur during the isolation period, the study’s estimates of the intensity of the hidden transmission of the new coronavirus tend to be conservative, and the actual risk of hidden transmission is likely to be greater. Therefore, the Government should take these risks into account in the study of whether to relax the epidemic prevention measures.
In response, CNN cited other recent research that found that the public can help protect themselves from the threat of hidden transmission by wearing masks properly where necessary.