Background The SARS-CoV-2 infection has emerged as a rapidly spreading infection. Today it is relatively easy to isolate Covid-19 symptomatic cases, while remains problematic to control the disease spread by infected but symptom-free individuals. The control of this possible path of contagion requires drastic measures of social distancing, which imply the suspension of most activities and generate economic and social issues. This study is aimed at estimating the percentage of asymptomatic SARS-CoV-2 infection in a geographic area with relatively low incidence of Covid-19. Methods Blood serum samples from 388 healthy volunteers were analyzed for the presence of anti-SARS-CoV-2 IgG by using an ELISA assay based on recombinant viral nucleocapsid protein. Results We found that 7 out of 388 healthy volunteers, who declared no symptoms of Covid-19, like fever, cough, fatigue etc., in the preceding 5 months, have bona fide serum anti-SARS-CoV-2 IgG, that is 1.8% of the asymptomatic population (95% confidence interval: 0.69–2.91%). Conclusions The estimated range of asymptomatic individuals with anti-SARS-CoV-2 IgG should be between 26,565 and 112, 350. In the same geographic area, there are 4665 symptomatic diagnosed cases. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-021-06054-2.
【저자키워드】 COVID-19, SARS-CoV-2, IgG, Disease prevalence, Asymptomatic individuals, 【초록키워드】 fatigue, social distancing, SARS-COV-2 infection, Infection, cough, activity, Spread, serum, Viral, Asymptomatic individuals, Asymptomatic, anti-SARS-CoV-2 IgG, symptomatic, Fever, incidence, disease spread, ELISA assay, Contagion, no symptoms, Suspension, no symptom, supplementary material, 95% confidence interval, healthy volunteers, measure, symptomatic cases, viral nucleocapsid protein, serum sample, asymptomatic individual, Result, analyzed, diagnosed, the disease, generate, individuals, drastic, healthy volunteer, 【제목키워드】 Asymptomatic, disease incidence,