Nature issues a dispute on whether to report asymptomatic new coronavirus infection

February 22, 2020 / Biovalley bio on / -- researchers worry that the number of people infected with the coronavirus officially reported in China does not include those who have been tested positive for the virus but have no symptoms They are concerned that the practice masks the true scale of the outbreak But public health experts say China is right to give priority to tracking patients who spread the disease Since the outbreak, China's National Health Commission has released the number of infections per day, and researchers of infectious diseases outside China have relied on these data to simulate the spread and severity of the epidemic Earlier this month, officials in northeastern China's Heilongjiang Province announced that 13 people who were laboratory tested positive but without symptoms had been removed from the list of confirmed cases in the region Officials say they are following the committee's guidelines for reporting infections, which state that these people should be classified as "positive cases" rather than "confirmed cases." Only confirmed cases are mentioned in the committee's official daily report The situation in Heilongjiang has drawn attention to China's reporting standards These have gained attention since the February 7 update, allowing doctors to use chest scan images to confirm cases, rather than waiting days for laboratory tests Changes in the diagnostic criteria led to nearly 15000 new cases of infection in Hubei Province, the epicenter of the epidemic, last Monday Photo source: the https://cn.bing.com report requires Wu Zunyou, chief epidemiologist at the China Center for Disease Control and prevention, to say that they have been asking for positive cases not to be included in the confirmed cases But those tested positive will be quarantined for 14 days and monitored by health authorities If they develop symptoms during that time, they are classified as confirmed cases Wu said a positive test does not necessarily mean a person is infected with the virus Laboratory tests often detect genetic material in throat or nasal swabs, but in some people, the virus may not have entered the cell and started replicating, he said However, it is not clear whether there are such "carriers", whose virus test is positive, but they are not actually infected "This is a major scientific issue," he said But several infectious disease researchers from outside China disagreed in an interview with nature Angela Rasmussen, a virologist at Columbia University in New York, said viruses usually need to replicate in their hosts to reach detectable levels If the virus is in a person's nose but doesn't infect any cells, she said, "I wonder if the virus in the nose swab that comes in contact this way can be detected "Ignoring these cases from official statistics gives the impression that the virus is more serious than it is," said Ian Mackay, a virologist at the University of Queensland Mackay said it could mislead other countries that are trying to prepare for the most likely impact of the epidemic, known as covid-19, on their populations The loss of contact with Michael Mina, an infectious disease immunologist and epidemiologist at Harvard T.H Chan School of public health, said that not counting asymptomatic cases would also hinder efforts to model viruses to understand their scope and spread Epidemiologists are trying to piece together the chain of transmission, which may include asymptomatic infections, Mina said He and other researchers suspect that there are far more people infected than the 74000 that have been reported, and that most cases may be asymptomatic if tested positive Who spokesman Tarik JA? Arevi? From a public health point of view, it makes sense to focus on symptomatic patients in China because it seems that these people are the ones who transmit the virus to others, he said Source: stringer Getty Mina said China may also be giving priority to patients and keeping them isolated rather than measuring the dynamics of the epidemic From a clinical point of view, it is reasonable to exclude asymptomatic patients from the number of cases, because if a person has no symptoms, they do not need treatment "If I put on my medical cap, I can also understand the decision not to count these people," he said Reference: David cyranski Scientists question China's decision not to report symptom free coronavirus cases Nature 2020 Doi: 10.1038/d41586-020-00434-5