The physicians conducted a study of blood samples of the inhabitants of the Chinese city of Wuhan, which became the epicenter of coronavirus distribution in the world late last year, and found that by early summer 2020, about 4% of the study had antibodies to COVID-19. The experts’ findings were published in an article in JAMA Network Open magazine on Friday, October 23.
The study was conducted at Tongji Hospital of Huazhong University of Science and Technology from March 27 to May 26. Samples were collected from just over 35,000 residents over the age of 18. At that none of the participants had COVID-19 in their anamnesis.
“This study showed that seropositive prevalence was 3.9% in a cohort of 35 040 people in Wuhan, China. Most people were only positive for IgG antibodies to SARS-CoV-2, indicating a previous infection,” the researchers emphasized.
The presence of antibodies during the experiment was more common in urban districts than in the suburbs. Moreover, antibodies were more frequently detected in women (4.4%) than in men (3.3%). At the same time, the prevalence of antibodies among the tested samples was higher in people over 60.
“It is possible that older people had a higher proportion of concomitant diseases that may contribute to SARS-CoV-2 infection and increase the severity of COVID-19,” the researchers suggested.