Pollán, Marina
Pérez-Gómez, Beatriz
Pastor-Barriuso, Roberto
Oteo, Jesús
Hernán, Miguel A
Pérez-Olmeda, Mayte
Sanmartín, Jose L
Fernández-García, Aurora
Cruz, Israel
Fernández de Larrea, Nerea
Molina, Marta
Rodríguez-Cabrera, Francisco
Martín, Mariano
Merino-Amador, Paloma
León Paniagua, Jose
Muñoz-Montalvo, Juan F
Blanco, Faustino
Yotti, Raquel
2020-08-18T19:21:18Z
2020-08-18T19:21:18Z
2020
0140-6736
https://doi.org/10.1016/
http://hdl.handle.net/20.500.12010/11933
Background Spain is one of the European countries most affected by the COVID-19 pandemic. Serological surveys are
a valuable tool to assess the extent of the epidemic, given the existence of asymptomatic cases and little access to
diagnostic tests. This nationwide population-based study aims to estimate the seroprevalence of SARS-CoV-2 infection
in Spain at national and regional level.
Methods 35883 households were selected from municipal rolls using two-stage random sampling stratified by
province and municipality size, with all residents invited to participate. From April 27 to May 11, 2020, 61 075 participants
(75·1% of all contacted individuals within selected households) answered a questionnaire on history of symptoms
compatible with COVID-19 and risk factors, received a point-of-care antibody test, and, if agreed, donated a blood
sample for additional testing with a chemiluminescent microparticle immunoassay. Prevalences of IgG antibodies
were adjusted using sampling weights and post-stratification to allow for differences in non-response rates based on
age group, sex, and census-tract income. Using results for both tests, we calculated a seroprevalence range maximising
either specificity (positive for both tests) or sensitivity (positive for either test).
Findings Seroprevalence was 5·0% (95% CI 4·7–5·4) by the point-of-care test and 4·6% (4·3–5·0) by immunoassay,
with a specificity–sensitivity range of 3·7% (3·3–4·0; both tests positive) to 6·2% (5·8–6·6; either test positive), with
no differences by sex and lower seroprevalence in children younger than 10 years (<3·1% by the point-of-care test).
There was substantial geographical variability, with higher prevalence around Madrid (>10%) and lower in coastal
areas (<3%). Seroprevalence among 195 participants with positive PCR more than 14 days before the study visit ranged
from 87·6% (81·1–92·1; both tests positive) to 91·8% (86·3–95·3; either test positive). In 7273 individuals with
anosmia or at least three symptoms, seroprevalence ranged from 15·3% (13·8–16·8) to 19·3% (17·7–21·0). Around a
third of seropositive participants were asymptomatic, ranging from 21·9% (19·1–24·9) to 35·8% (33·1–38·5). Only
19·5% (16·3–23·2) of symptomatic participants who were seropositive by both the point-of-care test and immunoassay
reported a previous PCR test.
Interpretation The majority of the Spanish population is seronegative to SARS-CoV-2 infection, even in hotspot areas.
Most PCR-confirmed cases have detectable antibodies, but a substantial proportion of people with symptoms compatible
with COVID-19 did not have a PCR test and at least a third of infections determined by serology were asymptomatic.
These results emphasise the need for maintaining public health measures to avoid a new epidemic wave.
11 páginas
image/jepg
The Lancet
reponame:Expeditio Repositorio Institucional UJTL
instname:Universidad de Bogotá Jorge Tadeo Lozano
SARS-CoV-2
Spain
Seroepidemiological study
Prevalence of SARS-CoV-2 in Spain (ENE-COVID): a nationwide, population-based seroepidemiological study
Artículo
Síndrome respiratorio agudo grave
COVID-19
SARS-CoV-2
Coronavirus
info:eu-repo/semantics/embargoedAccess
info:eu-repo/semantics/acceptedVersion
Acceso restringido
https://doi.org/10.1016/