Professor Liu Min's team from the School of Public Health of Peking University recently published the article "The Proportion of Asymptomatic Infected People in the Global COVID-19 Test population and confirmed patients: a systematic review and meta-analysis" in the Journal of the American Medical Association. Through the analysis of 95 papers and 30 million people infected with new crown pneumonia, it was found that the proportion of asymptomatic infected people with new crown pneumonia exceeded 40%. It is a reminder of the difficulty of covid-19 prevention and control and the need for comprehensive nucleic acid screening in the event of an outbreak.
Medical staff conduct nucleic acid testing samples for the public. Photo by Xinhua News Agency reporter Zhang Haoran
It is understood that in order to further confirm the proportion of asymptomatic infected people with new crown pneumonia, Liu Min's team did a large-scale retrospective study, screening out 2860 studies related to new crown and asymptomatic infections around the world from the database, and after review and selection, 95 papers analyzing the proportion of asymptomatic infected people were identified, and these 95 studies covered nearly 30 million independent individuals. Through the analysis of these 95 papers, the research team found that a total of 29776306 people received nucleic acid testing, and 11,516 asymptomatic infected people, accounting for 0.25% of the total number of people tested. Among them, the proportion of asymptomatic infected people in nursing homes reached 4.52%, the proportion of asymptomatic infected people in air or cruise passengers was 2.02%, and the proportion of asymptomatic infected people in pregnant women was 2.34%.
Further analysis of the proportion of infected people in the asymptomatic, 18 of these 95 papers specifically study asymptomatic infected people, the researchers removed these 18 papers, the remaining 77 papers further analyzed, of these 77 papers, a total of 19884 people confirmed by nucleic acid test infection of the new crown, of which 11069 people were asymptomatic infected, the proportion of asymptomatic infected people up to 40.50%. Among the infected, the asymptomatic rate of pregnant women was the highest, reaching 54.11%, air or cruise passengers 52.91%, and 47.53% of people in nursing homes.
This large-scale statistical analysis shows that the proportion of asymptomatic infections in the tested population is 0.25%, and among the people diagnosed with new crown pneumonia, the proportion of asymptomatic infections is as high as 40.50%.
Liu Min said that the proportion of asymptomatic infected patients among confirmed patients in airlines and cruise ship passengers is very high, more than 50%, which reminds us that for those entering the country from abroad, it is necessary to conduct nucleic acid testing and isolation, which is very important to prevent community transmission.
Liu Min also stressed that asymptomatic infected people also carry the new crown virus, and the viral load is comparable to that of symptomatic infected people, and because of asymptomatic, it is often found later and the risk of transmission is greater. Therefore, for asymptomatic infected people, the same isolation and close contact tracing should be carried out with symptomatic infected people.
(Guangming Daily all-media reporter Jin Haotian)
Source: Guangming Daily all-media reporter Jin Haotian
Photo: Xinhua News Agency
Editor-in-charge: Wang Zimo
Editor: Wu Yaqi Xing Yanyan