Rubilar, PaolaHirmas Adauy, MacarenaMatute, María IsabelBrowne, JorgeLittle, CedricRuz, GonzaloAguilera, XimenaAvila, CarlosVial, PabloGutknecht Mackenzie, Tania2023-12-052023-12-052022Rubilar P, Hirmas M, Matute I, Browne J, Little C, Ruz G, et al. Seroprevalence and estimation of the impact of SARS-CoV-2 infection in older adults residing in Long-term Care Facilities in Chile. Medwave 2022;22(03):002553https://repositorio.udd.cl/handle/11447/8131Introduction Older adults are at a higher risk of severe illness and death from COVID-19. This vulnera bility increases in those who live in long-term care facilities due to overcrowding, greater physical dependence, and contact with health workers. Evidence on the impact of the pan demic on these establishments in low- and middle-income countries has been scant. This study aims to determine the seroprevalence of SARS-CoV-2 in older people residing in long-term care facilities and estimate the impact of infection after the first wave of the pandemic. Methods A cross-sectional design with 2099 residents in three regions of Chile was carried out be tween September and November 2020. Measurement of antibodies was performed with a rapid test. The impact of SARS-CoV-2 infection was estimated with seropositive residents, those who had a history of positive polymerase chain reaction tests, and those who died from COVID-19. Bivariate analysis with the region, sex, age, history of COVID-19, physical dependence, and serological results were performed. In addition, we performed a correla tion analysis between the seroprevalence of the centers by the municipality and the rate of confirmed cases. Results The seroprevalence of SARS-CoV-2 antibodies in the three regions was 14.7% (95% confi dence interval: 13.2 to 16.3%), the infection impact was 46.4%, and the fatality rate was 19.6%. A significant correlation was found between the seroprevalence of older adults re siding in long-term care facilities and the cumulative incidence by municipalities. Conclusions The seroprevalence of older adults residing in long-term care facilities was higher than the general population. The high impact of infection among this population at the end of the first wave of the COVID-19 pandemic is similar to other countries. The centers' environ ment is directly related to COVID-19 infection. Morbidity and mortality monitoring sys tems should be implemented promptly to establish prevention and control measur11 p.enCOVID-19 Serological TestingLong-Term CareAgedSARS-CoV-2Articlehttps://doi.org/10.5867/medwave.2022.03.002553