Wuhan City Health Commission informed in the early hours of March 22 that the web rumor of a media reporter in Hubei’s personal experience “my most memorable day” disclosed that there were new confirmed cases in Wuhan is not true. In the afternoon of March 20, the net rumor Hanjiadun Street comprehensive community about “last night Lishui Kangcheng district and new cases” “important notice”. The community resident Zhang Moumou was found to be asymptomatic infected, not a confirmed case, and was tested negative again on the 20th. The People’s Daily Health Client interviewed Yu Chuanhua, a professor of epidemiology and health statistics at Wuhan University, to explain the reason for this. Why is it not counted as a confirmed case? “Asymptomatic infections can be understood as people who have no clinical symptoms such as fever or cough, but whose nucleic acid test is positive again.” Yu Chuanhua mentioned that people with asymptomatic infections also see no changes in some ancillary tests, such as no problems with white blood cell counts as well as lymphocyte counts in early blood routines, followed by normal chest images. “A positive test is not necessarily a patient with new coronary pneumonia, as there may also be false positives, so continued observation is needed.” Laboratory tests usually detect the genetic material of the virus in throat or nasal swabs, but in some people, the virus may not have entered the cells and started replicating, Yu Chuanhua told People’s Daily Health Client. The number of coronavirus infections reported in the country does not include asymptomatic infected people who test positive for the virus. “If a particular test is not 100% accurate, then there is the potential for false negatives (missed diagnoses) or false positives (misdiagnoses). For example, a given test finds 98 positives out of 100 patients diagnosed with neoconiosis (98% sensitivity, 2% false negative rate); 99 negatives out of 100 patients with non-neoconiosis (99% specificity, 1% false positive rate). When the infection rate is low (e.g., 1/2000), only 5 of 100 positive results for this test are patients; however, when the infection rate is 10% in suspected patients with a history of exposure during an epidemic of the disease, then 95 of 100 positive results for this test are true patients. The latter is called the positive predictive value, and it is closely related to the infection rate. The higher the rate of infection, the greater the positive predictive value.” Yu Chuanhua said that a “positive” nucleic acid test is not the same as an “infection” with Newcastle pneumonia, as in the case of Zhang Moumou, a resident of the Hanjiadun Street integrated community, where a “positive” nucleic acid test was actually a false The actual situation is false positive. Are asymptomatic infected people infectious? The National Health Commission released the “New Coronavirus Pneumonia Treatment Plan (Trial Version 5)” on Feb. 6, in which it was first suggested that “asymptomatic infected people can also be the source of infection”. “Since the infection is confirmed, asymptomatic infected people are contagious and those who test positive will be quarantined for 14 days to be tested by the health department. If symptoms appear during this period, they will be classified as confirmed cases.” Yu Chuanhua said it makes sense for the country to focus on the number of symptomatic patients because these are the people who may be the transmitters of the virus. Through its observations of Middle East Respiratory Syndrome coronavirus (MERS), WHO found that transmission of the coronavirus through asymptomatic patients is very rare, so WHO concluded: asymptomatic patients may not be the main transmitters of the virus. Do asymptomatic infected patients need to receive treatment? “Even asymptomatic infected people need to be isolated and closely observed, and also need appropriate medical interventions, but pharmaceutical interventions with high side effects are not advocated, which can be safer.” Yu Chuanhua cautioned that isolation and close observation may be less risky for asymptomatic or minimally symptomatic patients. The numbers reported by asymptomatic infected patients are not part of the mandatory disclosure. According to the relevant provisions of the Pneumonia Prevention and Control Program for Novel Coronavirus Infections (4th Edition), asymptomatic infected patients found in various medical and health institutions at all levels should be placed in centralized isolation for 14 days and reported directly on the Internet within two hours. After receiving reports of asymptomatic infections, county and district-level disease control agencies should complete investigations of cases within 24 hours, promptly register close contacts, and take isolation measures. Zeng Yixin, deputy director of the National Health Commission, also said at the conference, “If it is an asymptomatic infected person who develops symptoms during centralized isolation, this time can be reported as a confirmed case and announced to the public.” Content source: Health Times