New research casts doubt on collective immunity against COVID-19

Spanish research questioned the feasibility of collective immunity as a way to combat the coronavirus pandemic. Spain is one of the European countries most affected by the COVID-19 pandemic, and a serological survey was conducted there. Such studies help assess the extent of the epidemic, given the presence of asymptomatic cases and limited access to diagnostic tests. This nationwide population-based study aims to assess the seroprevalence of SARS-CoV-2 infection in Spain at the national and regional levels. The results are published in the medical journal Lancet.

Research conducted among 60,000 people showed that only 5% of the population of Spain developed antibodies.

Collective immunity is achieved when enough people become immune to the virus to stop its spread.

The report said that the prevalence of antibodies to COVID-19 was below 3% in coastal regions, but higher in areas of Spain with widespread outbreaks.

Despite the great damage from COVID-19 in Spain, prevalence estimates remain low and clearly insufficient to ensure collective immunity, the study says. In this situation, measures of social distance and efforts to identify and isolate new cases and their contacts are extremely important for combating the epidemic in the future.



This study is currently the largest of its kind in Europe. Similar studies have been conducted in China and the United States, and the key conclusion from these representative cohorts is that most of the population seemed to remain unaffected by coronavirus even in areas with widespread viral circulation.

Most of the Spanish population is seronegative for SARS-CoV-2 infection, even in areas of hot spots. In most PCR-confirmed cases, detectable antibodies are detected. But in a significant proportion of people with symptoms compatible with COVID-19, a PCR test was not performed, and at least a third of serologically determined infections were asymptomatic. These results emphasize the need to maintain public health measures in order to avoid a new epidemic wave.

Now in Spain, more than a quarter of a million cases of the disease and at least 28 thousand deaths are registered.

Collective immunity can be achieved either through widespread vaccination or in the case of infection with a sufficient number of people and recovery. If enough people are immune to the disease, it is unlikely that it will spread from person to person.

There is currently no coronavirus vaccine, although hundreds are being developed.