CNN reports:

Spain’s large-scale study on the coronavirus indicates just 5% of its population has developed antibodies, strengthening evidence that a so-called herd immunity to Covid-19 is “unachievable,” the medical journal the Lancet reported on Monday.

The findings show that 95% of Spain’s population remains susceptible to the virus. Herd immunity is achieved when enough of a population has become infected with a virus or bacteria — or vaccinated against it — to stop its circulation.

The European Center for Disease Control told CNN that Spain’s research, on a nationwide representative sample of more than 61,000 participants, appears to be the largest study to date among a dozen serological studies on the coronavirus undertaken by European nations.

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

There have been similar studies in China and the United States and “the key finding from these representative cohorts is that most of the population appears to have remained unexposed” to Covid-19, “even in areas with widespread virus circulation,” said a Lancet commentary published along with Spain’s findings. [Continue reading…]