A senior official in the World Health Organization has warned that herd immunity is not the panacea many believe it to be in combating the coronavirus.
Speaking with NBC, Dr. Mike Ryan, the WHO’s emergencies director, explained that herd immunity as a term was originally coined with regard to animals, where the deaths of some animals in order to save the rest of the herd was a reasonable course of action to take. “We need to be really careful when we use terms in this way around natural infection in humans, because it can lead to a very brutal arithmetic which does not put people and life and suffering at the center of that equation,” he said.
Despite infection rates climbing to 10% and possibly even close to 30% in some parts of the world, this is way below levels that would need to be reached in order to attain the so-called herd immunity, where the virus no longer spreads because most people have gained natural immunity via exposure and recovery. Health officials have estimated that around 60% of the population in any given area would have to be immune in order to stem the epidemic via natural means.
In Wuhan, China, where the novel coronavirus is thought to have originated, studies have indicated that only around three percent of people have Covid-19 antibodies in their blood; a similar in Spain showed similar results – around five percent of people were thought to have gained immunity. The highest reported results have been obtained in New York City, but even there, studies suggested that only around one in five people would test positive for antibodies.
Covid-19 is known to be highly contagious, and NBC quoted several officials who warned that a policy designed to attain herd immunity could lead to the death rate multiplying by a factor of 15. A further complication is that no one is absolutely sure whether having antibodies actually confers immunity for any appreciable length of time.