Household Clustering of SARS-CoV-2 in Community Settings: A Study from Rural Ecuador

• Published in: The American journal of tropical medicine and hygiene Vol. 103; no. 3; pp. 1207 - 1210
• Main Authors: Del Brutto, Oscar H, Costa, Aldo F, Mera, Robertino M, Recalde, Bettsy Y, Bustos, Javier A, García, Héctor H
• Format: Journal Article
• Language: English
• Published: United States Institute of Tropical Medicine 01.09.2020; The American Society of Tropical Medicine and Hygiene
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Antibodies, Viral - blood; Betacoronavirus; Case-Control Studies; Child; Cluster Analysis; Coronavirus Infections - epidemiology; COVID-19; Ecuador - epidemiology; Family Characteristics; Female; Households; Houses; Humans; Immunoglobulin G - blood; Immunoglobulin M - blood; Male; Middle Aged; Pandemics; Pneumonia, Viral - epidemiology; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Young Adult; Ecuador
• ISSN: 0002-9637; 1476-1645
• DOI: 10.4269/ajtmh.20-0688

The SARS-CoV-2 pandemic is now expanding into the developing world with devastating consequences. Departing from a population-based study in rural Ecuador where all adult individuals (aged 40 years or older) were tested for SARS-CoV-2 IgG and IgM antibodies, we expanded it to include a house-based case-control component assessing in-house clustering and other variables potentially associated with infection. We selected houses where exactly two study participants lived and were both seropositive (case-houses), and matched 1:1 to control-houses where both were seronegative. Younger household members had an antibody test performed. Infected household members were found in 33 (92%) case-houses and in only six (17%) control-houses. In 28/29 discordant house pairs, the case-house had seropositive household members and the control-house did not (odds ratio: 28; 95% CI: 4.6-1,144). Our data demonstrate strong in-house clustering of infection in community settings, stressing the importance of early case ascertainment and isolation for SARS-CoV-2 control.