ONLY 5.2 per cent of Spain’s population has had Covid-19 and developed antibodies, a study reveals.
This is a long way from the approximately 60 per cent considered necessary to achieve so-called herd immunity.
The results of the second wave of the national study on the seroprevalence of coronavirus also shows there are considerable geographical variations.
Provinces in the centre of the country have the highest percentages. In Soria the rate is 14.7 per cent, in Cuenca 14.2 per cent, 12.6 per cent in Segovia, 11.6 in Albacete and 11.4 per cent in Madrid. By contrast, the percentage in Huelva in Andalucia is just 1.2 per cent, and 1.6 per cent in Murcia and Tarragona.
In cities with more than 100,000 in habitants, immunity levels have gone up from the 6.4 per cent cited in the first advance of the study on May 13 to 6.8 per cent.
A further finding is that 80.5 per cent of the participants found to be positive in a PCR test carried out more than two weeks earlier had immunoglobulin G (IgG) antibodies. These are the most common type of antibody found in blood circulation, and checking these, the report authors believe, is the “most reliable” for these kinds of studies.
In suspected cases, or where infection has not been confirmed by a test, the prevalence of IgG was found to increase with the number of symptoms, and particularly the loss of the sense of smell.
In asymptomatic cases, IgG was detected in only 2.8 per cent.
A total of 63,564 people took part in the study, which was carried out by the Health Ministry in collaboration with the Carlos III Health Institute, the National Institute of Statistics and regional governments, between May 18 and June 1.