A study by the University of Athens on nearly 5,000 members and students found that almost 50% of those with antibodies against the novel coronavirus had not shown any symptoms and did not know they were carriers.
Publicized recently in the latest Vaccines journal, the study contained the results of testing on 4,996 volunteers (aged 18-82 years, 34.5% men) from June to November 2020 and found that 1.6% of the participants had been infected with the SARS-CoV-2 virus at some point. However, 49% of the seropositive cases reported that that had no symptoms whatsoever – such as a low but persistent fever, muscle pain and fatigue, loss of taste and smell or a cough – while roughly one-third had no idea how they could have become infected.
Another interesting finding is that the level of antibodies was similar between infected volunteers that did show symptoms and those that did not, irrespective of age and gender.
“The high percentage of unsuspected asymptomatic active cases, which may contribute to community transmission for more days than that of cases who are aware and self-isolate, underscores the necessity of measures across the population for the efficient control of the pandemic,” the authors note.
Unsurprisingly, the volunteers with the highest rate of antibodies came from the School of Health Sciences, whose students and faculty work at coronavirus referral hospitals run by Athens University.