Spanish coronavirus antibody studies add evidence to herd immunity

This adds to the findings of an antibody study involving 2,766 participants in Geneva, Switzerland, was published in Lancet on June 11.

There are similar studies in China and the United States and “the key finding of this representative group is that a large portion of the population seems to remain unexposed” at Covid-19, “even in areas with extensive viral circulation,” said one Lancet’s comments were published along with Spanish findings.

“In light of these findings, any proposed approach to achieving herd immunity through natural infections is not only highly unethical, but also unachievable,” said Lancet’s commentary writer Isabella Eckerle, head of the Geneva Center for Developing Viral Diseases, and Benjamin Meyer, a virus expert at the University of Geneva.

Doctors are not sure whether having antibodies to coronavirus means a person cannot be infected again. It is unclear how long or how well antibodies protect people from viruses.

Spain’s peer-reviewed study began in April while the country remained tightly locked, and carried out by leading government research and epidemiology institutions.

“The relatively low seroprevalence observed in the context of an intense epidemic in Spain can serve as a reference to other countries. At present, herd immunity is difficult to achieve without receiving collateral damage from many deaths in vulnerable populations and overloading the health system,” the report wrote. that.

The lead author of the Spanish study, Marina Pollán, who is the director of the National Center for Epidemiology, told CNN: “Some experts have calculated that about 60% of seroprevalence can mean herd immunity. But we are very far from reaching that number.”

Spain has become one of the countries in Europe hardest hit by the corona virus, with more than 28,000 deaths and 250,000 cases.

Lancet published the results of the first phase of the Spanish study, conducted from 27 April to 11 May, which showed a national antibody prevalence of 5%.

But the Madrid metropolitan area, the hardest hit in the country by Covid-19, has a prevalence of more than 10%, and Barcelona that is densely urbanized has 7%, while many other coastal provinces have much lower rates.

Likewise, the Geneva prevalence was 10.8% in Swiss studies conducted from April to early May, Lancet reported.

“With the majority of the population naive due to infection, the circulation of the virus can quickly return to the initial pandemic dimension in the second wave after the steps are taken,” commented the authors Lancet Eckerle and Meyer writing about the findings.

The results of the second Spanish study phase released on June 4, showed a national prevalence of 5.2%, only slightly higher than in the first phase. The results of the third and final phase were announced publicly on Monday; they showed that national prevalence remained at 5.2%, Pollán said.