Post-vaccination seropositivity against SARS-CoV-2 in peruvian health workers vaccinated with BBIBP-CorV (Sinopharm).

OBJECTIVE: To estimate the prevalence of post-vaccination seropositivity against SARS-CoV-2 and identify its predictors in Peruvian Social Health Insurance (EsSalud) personnel in 2021. METHODS: We conducted a cross-sectional study in a representative simple stratified sample of EsSalud workers. We evaluated IgG anti-SARS-CoV-2 antibodies response (seropositivity) by passive (previous infection) and active immunization (vaccination), and epidemiological and occupational variables obtained by direct interview and a data collection form. Descriptive and inferential statistics were used with correction of sample weights adjusted for non-response rate, and crude and adjusted odds ratio (OR) and geometric mean ratio (GMR) with their respective 95% confidence intervals (95%CI) were estimated. RESULTS: We enrolled 1077 subjects. Seropositivity was 67.4% (95%CI: 63.4-71.1). Predictors of seropositivity were age (negative relation; p < 0.001), previous infection (aOR = 11.7; 95%CI: 7.81-17.5), working in COVID-19 area (aOR = 1.47; 95%CI: 1.02-2.11) and time since the second dose. In relation to antibody levels measured by geometric means, there was an association between male sex (aGMR = 0.77; 95%CI: 0.74-0.80), age (negative relation; p < 0.001), previous infection (aGMR = 13.1; 95%CI:4.99-34.40), non-face-to-face/licensed work modality (aGMR = 0.78; 95%CI: 0.73-0.84), being a nursing technician (aGMR = 1.30; 95%CI: 1.20-1.41), working in administrative areas (aGMR = 1.17; 95%CI: 1.10-1.25), diagnostic support (aGMR = 1.07; 95%CI: 1.01-1.15), critical care (aGMR = 0.85; 95%CI: 0.79-0.93), and in a COVID-19 area (aGMR = 1.30; 95%CI: 1.24-1.36) and time since receiving the second dose (negative relation; p < 0.001). CONCLUSIONS: Seropositivity and antibody levels decrease as the time since receiving the second dose increases. Older age and no history of previous infection were associated with lower seropositivity and antibody values. These findings may be useful for sentinel antibody surveillance and the design of booster dose strategies.

Pruebas rápidas de anticuerpos contra el SARS-CoV-2: reporte de una experiencia en un Servicio de Emergencia / Rapid testing of SARS-CoV-2 antibodies: Report of an experience in an Emergency Service

Objetivo: Determinar la positividad y los patrones de los resultados positivos de las pruebas rápidas de anticuerpos contra el SARS-CoV-2 en los pacientes atendidos en un Servicio de Emergencia. Materiales y métodos: Evaluación retrospectiva de las pruebas rápidas de anticuerpos contra el SARS-CoV-2 aplicadas durante el mes de junio/2020 en el Servicio de Emergencia del Hospital EsSalud G. Almenara, Lima, Perú. Resultados: Fueron evaluadas 1 805 pruebas realizadas en igual número de pacientes. En 864 (48%) de las pruebas fueron positivas, en el siguiente orden: patrón combinado de IgM-IgG en 635 (73%), IgM en 134 (16%) y, finalmente, de IgG en 95 (11%). Conclusiones: La positividad de las pruebas rápidas de anticuerpos contra el SARS-CoV-2 fue de 48%, y el patrón combinado de IgM-IgG fue el más frecuente, en tres cuartas partes de los casos confirmados.