Spanias helsedept finansierte et storstudium for å kartlegge ev. tilstedeværelse av antistoff, i befolkningen generelt og i sterkt rammede områder.
Under 5% av befolkningen registrerte slike og man vet ikke i hvilken utstrekning dette beskytter. Andelen er selvsagt langt unna flokkimmunitet og man anbefaler at sosial distansering og andre tiltak opprettholdes. Totalt over 61 tusen deltakere i studien.
Kortversjonen:
Spain's large-scale study on the coronavirus indicates just 5% of its population has developed antibodies,
strengthening evidence that a so-called herd immunity to Covid-19 is "unachievable," the medical journal the Lancet reported on Monday.
Spain's large-scale study on the coronavirus indicates just 5% of its population has developed antibodies, strengthening evidence that a so-called herd immunity to Covid-19 is "unachievable," the medical journal the Lancet reported on Monday.
amp.cnn.com
Langversjonen:
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.
Funding
Spanish Ministry of Health, Institute of Health Carlos III, and Spanish National Health System.