RESUMO
This study evaluates a population-based screening of asymptomatic people, using a rapid antigen diagnostic test (RADT), in areas of high transmission. To detect sources of SARS-CoV-2 infection, nasopharyngeal samples were taken and were tested using RADT. Confirmatory RT-qPCR tests were performed in both positive and negative cases. The internal validity of the RADT, the prevalence of infection, and the positive and negative predictive values (PPV and NPV) were estimated, based on the percentages of confirmed cases with 95% confidence interval. Of the 157,920 people registered, 50,492 participated in the screening; 50,052 were negative, and 440 were positive on the RADT (0.87%). A total of 221 positive RADT samples were reanalysed using RT-qPCR and 214 were confirmed as positive (96.8%; 95% CI: 93.5-98.7%), while 657 out of 660 negative RADT samples were confirmed as RT-qPCR negative (99.5%; 95% CI 98.7-99.9%). The sensitivity obtained was 65.1% (38.4-90.2%) and the specificity was 99.97% (99.94-99.99%). The prevalence of infection was 1.30% (0.95-2.13%). The PPVs were 95.4% (85.9-98.9%) and 97.9% (93.3-99.5%), respectively, while the NPVs were 99.7% (99.4-100%) and 99.2% (98.7-100%), respectively. The high specificity found allow us to report a high screening performance in asymptomatic patients, even in areas where the prevalence of infection was less than 2%.
RESUMO
OBJECTIVE: To evaluate the prevalence and associated factors with SARS-CoV-2 infection in general practitioners and nurses of primary care centers and nursing homes in the health area of León (Spain). MATERIALS AND METHODS: Cross-sectional study in a convenience sample of professionals from 30 health centers and 30 nursing homes from the primary care management division of the Healthcare Area of Leon. The work center, type of profession, COVID-19 infection, level of exposure, compliance with preventive measures, isolation (if required) and diagnostic tests carried out were collected. The determination of infection was made by differentiated rapid diagnostic test (dRDT), using a finger-stick whole-blood sample. The association of variables with infection was assessed by multivariable non-conditional logistic regression. The true prevalence of SARS-CoV-2 infection was calculated according to two scenarios for RDT (Sensitivity=0.6 and Specificity=0.985; Sensitivity=0.8 and Specificity=1). RESULTS: The true prevalence of SARS-CoV-2 infection was between 4.9% - 11.0%. The observed prevalence was 5.9%, being higher in nursing home compared to primary care centers (9.5% vs. 5.5%). No statistically significant differences were observed by sex, type of professional, level of exposure or compliance with preventive measures. CONCLUSIONS: The prevalence of SARS-CoV-2 infection in this group is low. A high number of professionals remain susceptible to SARS-CoV-2 infection and therefore protective measures should be taken, especially in nursing home professionals
OBJETIVO: Evaluar la prevalencia y los factores asociados a la infección por SARS-CoV-2 en médicos y enfermeras de centros de atención primaria y residencias de ancianos del área de salud de León (España). MATERIAL Y MÉTODOS: Estudio observacional realizado en una muestra de conveniencia de profesionales de 30 centros de salud y 30 residencias de ancianos, de la Gerencia de Atención Primaria del área de salud de León. Se recogió información del centro de trabajo, tipo de profesión, infección por COVID-19, nivel de exposición, cumplimiento de medidas preventivas, aislamiento (si fue requerido) y test diagnósticos realizados. La determinación de infección fue llevada a cabo mediante prueba de diagnóstico rápido diferenciado (PDRd), usando muestra de sangre capilar. La asociación de las variables con la infección se evaluó mediante regresión logística multivariable no condicional. La prevalencia real de infección por SARS-CoV-2 fue calculada de acuerdo a dos escenarios para el PDRd (Sensibilidad=0,6 y Especificidad=0,985; Sensibilidad=0,8 y Especificidad=1). RESULTADOS: La prevalencia real de infección por SARS-CoV-2 se encontró entre 4,9%-11,0%. La prevalencia observada fue de 5,9%, siendo mayor en trabajadores de residencias de ancianos que de centros de salud de atención primaria (9,5% vs 5,5%). No hubo diferencias estadísticamente significativas por sexo, tipo de profesional, nivel de exposición o cumplimiento de medidas preventivas. CONCLUSIONES: La prevalencia de la infección por el SARS-CoV-2 en este grupo es baja. Un gran número de profesionales siguen siendo susceptibles a la infección por el SARS-CoV-2 y, por lo tanto, medidas de protección deben ser adoptadas, especialmente en los profesionales de las residencias de ancianos
