The results show that 95% of the Spanish population is still susceptible to the virus. Herd immunity is achieved when a sufficient population has been infected with, or vaccinated against, a virus or bacteria to stop its movement.
The European Center for Disease Control told CNN that Spain’s research, in a nationally representative sample of more than 61,000 participants, appears to be the largest study to date among a dozen serological studies on the coronavirus conducted by European nations.
“In light of these findings, any proposed approach to achieving herd immunity through natural infection is not only unethical but also unachievable,” said the authors of Lancet’s comments, Isabella Eckerle, director of the Center for Geneva for Emerging Viral Diseases, and Benjamin Meyer, virologist at the University of Geneva.
Doctors do not know if having antibodies to the coronavirus means that someone cannot re-become infected. It is unclear how long or how well the antibodies protect people from the virus.
The peer-reviewed study in Spain began in April, while the nation remained in strict lockout, and was conducted by the government’s major research and epidemiology agencies.
“The relatively low seroprevalence observed in the context of an intense epidemic in Spain could serve as a reference for other countries. Currently, collective immunity is difficult to achieve without accepting the collateral damage of many deaths in the susceptible population and the overload of health systems. “Reads the report.
The main author of the Spanish study, Marina Pollán, who is director of the National Center for Epidemiology, told CNN: “Some experts have calculated that around 60% of seroprevalence could mean collective immunity. But we are very far from achieving that number” .
Spain has been one of the countries in Europe most affected by the coronavirus, with more than 28,000 deaths and 250,000 cases.
The Lancet published the results of the first phase of the study in Spain, carried out from April 27 to May 11, which showed a national prevalence of antibodies of 5%.
But the Madrid metropolitan area, the most affected in the country by Covid-19, had a prevalence of more than 10%, and the densely urban Barcelona had 7%, while many other coastal provinces had much lower rates.
Similarly, the prevalence of Geneva was 10.8% in the Swiss study conducted between April and early May, The Lancet reported.
“Since a large majority of the population does not have an infection, the circulation of the virus can quickly return to the first dimensions of the pandemic in a second wave once measures are lifted,” wrote the authors of Lancet’s comments, Eckerle. and Meyer, on the findings.
The results of the second phase of the study in Spain were published on June 4, showing a national prevalence of 5.2%, slightly higher than that of the first phase. The results of the third and final phase were released on Monday; They showed that the national prevalence remained at 5.2%, Pollán said.
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