RESUMEN
We conducted a nationwide study of the prevalence of severe acute respiratory syndrome coronavirus 2 infection in the Faroe Islands. Of 1,075 randomly selected participants, 6 (0.6%) tested seropositive for antibodies to the virus. Adjustment for test sensitivity and specificity yielded a 0.7% prevalence. Our findings will help us evaluate our public health response.
Asunto(s)
Anticuerpos Antivirales/sangre , Betacoronavirus/inmunología , Técnicas de Laboratorio Clínico/estadística & datos numéricos , Infecciones por Coronavirus/epidemiología , Neumonía Viral/epidemiología , Adulto , COVID-19 , Prueba de COVID-19 , Infecciones por Coronavirus/sangre , Infecciones por Coronavirus/diagnóstico , Dinamarca/epidemiología , Femenino , Humanos , Masculino , Pandemias , Neumonía Viral/sangre , SARS-CoV-2 , Estudios Seroepidemiológicos , Adulto JovenRESUMEN
IMPORTANCE: The immunity following infection and vaccination with the SARS-CoV-2 Omicron variant is poorly understood. We investigated immunity assessed with antibody and T-cell responses under different scenarios in vaccinated and unvaccinated individuals with and without Omicron infection. We found that the humoral response was higher among vaccinated-naïve than unvaccinated convalescent. Unvaccinated with and without infection had comparable low humoral responses, whereas vaccinated with a second or third dose, independent of infection status, had increasingly higher levels. Only a minor fraction of unvaccinated individuals had detectable humoral responses following Omicron infection, while almost all had positive T-cell responses. In conclusion, primary Omicron infection mounts a low humoral immune response, enhanced by prior vaccination. Omicron infection induced a robust T-cell response in both unvaccinated and vaccinated, demonstrating that immune evasion of primary Omicron infection affects humoral immunity more than T-cell immunity.