Study on the Epidemiological Characteristics of SARS-CoV-2 Infection Based on Population of Zunyi, China

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new type of virus that firstly confirmed in Wuhan, China recently. SARS-CoV-2 mainly spread through droplets. Infection characteristics data of SARS-CoV-2 is still limited, especially about asymptomatic infection, familial aggregation infection and infection risk in family member.MethodsFrom 2nd January 2020 to 23th February 2020, we have screened 22,729 throat swab samples from individuals with either have contact history of imported personnel, out-of-city travel or residence history or flu-like symptoms during the past 14 days. SARS-CoV-2 RNA was extracted and detected by real-time PCR. Data were analyzed using SPSS version 19 (IBM, Armonk, NY, USA). The results were confirmed by the Pearson χ2 test; P ＜ 0.05 was considered statistically significant.Results35 SARS-CoV-2 positive patients were found, 22 were asymptomatic infection, and 31 were familial aggregation infection. Odds ratio of SARS-CoV-2 infection risk between family aggregated close contacts and overall close contacts was 29.40 (95％ confidence interval: 13.99 - 62.205, χ2 = 140.23, P ＜ 0.001); odds ratio of SARS-CoV-2 infection risk between family aggregated close contacts and non-family aggregated close contacts was 703.50 （95％ confidence interval: 89.53 - 5527.95, χ2 = 282.659, P ＜ 0.001). One SARS-CoV-2 positive patient infected 2.08 (25/12) people on average under social control without separate isolation.ConclusionsSocial control is effective in SARS-CoV-2 inhibition, but self-isolation and screening should be added as supplementary means to avoid familial aggregation infection and find out asymptomatic patients.