The research, published in Nature Medicine, June 18, highlights the risks of using COVID-19 ‘passport immunity’ and supports the prolonged use of public health interventions such as social distance and l isolation of high-risk groups, the researchers said.
Health authorities in some countries like Germany are debating the ethics and practicalities of allowing people who test positive for antibodies to move more freely than others who aren’t .
Research, which has studied the 37 symptomatic and 37 asymptomatic patients, has revealed that those who tested positive for the presence of IgG antibodies, one of the main types of antibody induced after infection, more than 90 % showed large decreases within 2-3 months.
The median decrease percentage was over 70% for symptomatic and asymptomatic patients.
To neutralize antibodies in serum, the average percentage decrease for people with symptoms was 11.7%, while for asymptomatic people it was 8.3%.
The study was conducted by researchers from the Chongqing Medical University, a branch of the China Center for Disease Control and Prevention and other institutes.
Jin Dong-Yan, a professor of virology at the University of Hong Kong who was not part of the research group, said the study does not deny the possibility that other parts of the immune system may offer protection.
Some cells memorize how to deal with a virus during the first infection and can muster effective protection if there is a second round of infection, he says. Scientists are yet to determine whether this mechanism works for the new coronavirus.
“The finding in this document does not mean that the sky is falling,” he said, also noting that the number of patients studied was small.
The reports of Roxanne Liu and Se Young Lee in Beijing; Editing by Miyoung Kim and Edwina Gibbs
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