First wave of the seroprevalence study: in Spain only 5% are immune to the virus

Only the 5% of Spaniards have passed the covid-19. This is the average, the variation by province is very wide, from 1.4% in Murcia to 14.2% in Soria.

The Ministry of Health and the Carlos III Health Institute have today revealed the results of the first wave of the ENE-COVID study, in which 2,600 of the 90,000 initially planned have participated so far. This still preliminary serological survey seeks to estimate the percentage of citizens who have been infected to date, the SARS-CoV-2 coronavirus in Spain, by municipality and by autonomous community.

Marina Pollán, director of the National Center for Epidemiology, explained that the 5% was precisely the result they expected obtain and they have now found that their prevalence estimates were not wrong. The study, which started in late April, spread over three waves and will last eight weeks. Each of the participants underwent a rapid test from a drop of blood and then blood was drawn for a serological analysis of covid-19 antibodies.

The result it is not surprising if we stick to the scant background that there is. The more massive the SARS-CoV-2 prevalence studies have been, the lower the percentage of people infected has been. The study carried out among 578 health workers from the Hospital Clínic offered 11.2%. "We we expected our percentage to be like a cap, a maximum, of the prevalence in the population ", told us Gemma Moncunill, one of the researchers after the study by the Institute of Global Health.

In addition to the study that is being carried out in Galicia, and which pointed to a prevalence of 1% of covid-19 positives in the community, the results of the 830,767 rapid tests that had been carried out throughout Spain up to the past also gave quite a few clues. May 7th. Although these tests are conditioned because they are not carried out randomly but with the intention of finding positives among the suspects, the percentage for all of Spain remained at 4.49% of infections. Galicia was precisely one of the least affected communities with 1.53% and Aragon, with 12.53%, the region where the most positives were detected.

Just today, a similar study measuring the prevalence of SARS-CoV-19 in France has been published in 'Science' and offers that a 4.4% of citizens in the neighboring country have been infected as of May 11. That is, neither they nor we have developed in this time the immunity that the experts they estimate enough to face a second wave with guarantees later this year. The so-called herd immunity is even further, between 60 and 70% of the population should have covid-19 antibodies, which would require more than four cycles of the disease in light of the first results of the study seroprevalence.