Nature: When will the coronavirus outbreak reach its peak?

China's coronavirus infection continues to grow at the rate of thousands of people a day, prompting many epidemiologists to constantly estimate when the epidemic will peak Some people believe that when the number of new infections reaches a peak in a day, the climax will occur at any time Others say it will be difficult to estimate the number of infections in a few months Public health officials want to know about when it will peak and how many people will be infected so they can prepare for hospitals and know when it is safe to lift travel restrictions Since late January, Wuhan, the epicenter of the outbreak, and several other nearby cities have been blocked Although the peak prediction is instructive, some researchers warn that it is difficult to achieve accuracy, especially when the data used in the model is incomplete "If you revise your forecast every week to say that the epidemic will peak in a week or two, you will be right in the end," said Brian labus, who works on disease surveillance at the University of Nevada in Las Vegas On February 11, Zhong Nanshan, a famous Chinese physician, led a team of experts to help control the epidemic He said the coronavirus could peak at the end of February Zhong Nanshan, who is known for discovering the SARS virus, said the situation will improve as the government takes control measures such as restricting travel and extending holidays, but he acknowledged that Wuhan is still in a "difficult period" So far, more than 70000 Chinese have been confirmed to have the disease - now known as covid-19 But many scientists think there are more cases than reported They don't think diagnostic tests and medical workers in China are enough to confirm all cases At least one model fits Zhong's estimate Researchers at the London School of hygiene and tropical medicine predict a peak at any time now Sebastian funk, a statistician involved in the model and analysis of the epidemic, said the prediction was based on an estimate that the average number of people infected in Wuhan before the closure of Wuhan on January 23 was 1.5 and 4.5, which is called the basic number of virus infections Funk published the analysis, which was not peer-reviewed, on the Institute's website on February 12 But he said the decline in new cases and deaths in Wuhan since the implementation suggests that the infection may have peaked (more than 14000 new cases were reported on 13 February, but the increase is due to changes in the way cases are diagnosed, not a real surge) Some researchers found that such a prediction was too optimistic Hiroshi nishiura, an epidemiologist at Hokkaido University in Japan, said people in most Chinese cities started returning to work last week after extended public holidays, opening up the possibility of a new communication chain Nishiura said the model he used estimated that the outbreak would peak sometime between the end of March and the end of May Nishiura said he had submitted a paper to medrxiv describing the model and its predictions To make such a prediction, he said his team considered the inherent transmission potential of the new virus - the basic number of clones known as R0, which is related to R The team estimated R0 to be between 1.5-2 His model, he said, offers a relatively simple view because it assumes that everyone in the population is susceptible It also reflects the view that many infected people are asymptomatic or in poor health and cannot seek treatment If so, he said, the number of cases currently reported significantly underestimates the number of infections Gabriel Leung, an epidemiologist at the University of Hong Kong, said nishiura's estimate was feasible He said the community has no immunity to sars-cov-2, a virus that causes covid-19, so "it will spread throughout the community." While these estimates sound extreme, it's not clear how deadly the virus is, Leung said In a paper published on February 9, Zhong Nanshan calculated the latest death rate, which showed that about 1.36 people died in every 100 cases But the number may be too high because the authors did not consider less serious cases (outside China, there have been 500 deaths ) Leung said it was not clear how controls such as travel bans and segregation affected the timing and severity of the peak Nishiura and funk say their models exclude these measurements because their effectiveness is uncertain Many scientists say control measures may not eventually reduce the number of infections But they can extend the peak time by slowing the spread, Leung said Leung said it was important to reduce the number of people infected during peak periods If everyone gets sick at the same time, "the whole society will stagnate," he said "Health services will be overwhelmed and people will die (BIOON Com)