Oct. 23 (UPI) -- Fewer than 4% of adults in Wuhan, China, tested positive for antibodies against COVID-19, putting the possibility of countries developing "herd immunity" against the virus without a vaccine in doubt, according to an analysis published Friday by JAMA Network Open.
The findings also suggest that those who experience mild disease or who have no outward symptoms of the virus may not develop long-lasting immunity to it naturally, the researchers said.
As a result, questions remain about whether it's possible for those who have the virus to develop an immune response against it naturally.
For this study, researchers at Tongji Hospital of Huazhong University of Science and Technology in Wuhan tested 35,040 adults for COVID-19 antibodies between March 26 and May 24.
None of the study participants tested positive for the antibody immunoglobulin M alone, while 3.2% had evidence of immunoglobulin G, the researchers said.
More women, at 4.4%, had antibodies against the virus than men, at 3.3%, the researchers said.
He noted, however, that as an epidemiologist, he is hesitant to generalize findings from 35,000 people to apply to an entire population. »