SARS-CoV-2 seroprevalence in Portugal following the third epidemic wave: results of the second National Serological Survey (ISN2COVID-19).
Infect Dis (Lond)
; 54(6): 418-424, 2022 06.
Article
en En
| MEDLINE
| ID: mdl-35023439
ABSTRACT
BACKGROUND:
Integrated approaches to surveillance of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection are important for public health actions. The 2nd National Serological Survey (ISN2COVID-19) aimed to characterize the extent of SARS-CoV-2 infection and vaccine-induced response in the Portuguese population following the third epidemic wave and the launch of the vaccination campaign.METHODS:
A cross-sectional study was performed using data on 8463 Portuguese 1-79 years of age, collected in February and March, 2021. SARS-CoV-2 IgM and IgG (anti-nucleoprotein and anti-spike) antibodies were determined in serum samples using Abbott Architect chemiluminescent microparticle assays. Post-infection and vaccine-induced seroprevalence with 95% confidence intervals (95%CI) were estimated in the overall sample and stratified by population characteristics.RESULTS:
The estimated seroprevalence was 15.5% (95%CI14.6-16.5%), of which 13.5% (95%CI 12.6-14.4%) was attributable to natural infection and 2.0% (95%CI1.7-2.4%) to vaccination. The lowest seroprevelence was observed in persons aged 70-79 years (8.9% 95%CI6.8-11.6), while seroprevalence in children (14.3%; 95%CI11.5-17.6%) and adolescents (12.9%; 95%CI10.5-15.7%) was similar to that of persons aged between 20 and 69 years. Of seropositive individuals, 22.6% (95%CI19.7-25.9%) did not report any symptoms in 6 months prior to interview. Of persons with completed vaccination (2-doses), 98.6% (95%CI 93.0-99.7%) had specific IgG (anti-S) antibodies.CONCLUSIONS:
After the third epidemic wave, the post-infection SARS-CoV-2 seroprevalence was 1.7 times higher than the cumulative incidence based on PCR-testing, but was higher (2.7 times) in children may be due to the high proportion of asymptomatic and mild infections.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
SARS-CoV-2
/
COVID-19
Tipo de estudio:
Observational_studies
/
Prevalence_studies
/
Risk_factors_studies
Límite:
Adolescent
/
Adult
/
Aged
/
Child
/
Humans
/
Middle aged
País/Región como asunto:
Europa
Idioma:
En
Revista:
Infect Dis (Lond)
Año:
2022
Tipo del documento:
Article
País de afiliación:
Portugal