The head of the World Health Organisation warned against the idea that herd immunity might be a realistic strategy to stop the pandemic, dismissing such proposals as “simply unethical”.
At a media briefing on Monday, WHO Director-General Tedros Adhanom Ghebreyesus said health officials typically aim to achieve herd immunity by vaccination. Tedros noted that to obtain herd immunity from a highly infectious disease such as measles, for example, about 95% of the population must be immunised.
“Herd immunity is achieved by protecting people from a virus, not by exposing them to it,” he said. Some researchers have argued that allowing Covid-19 to spread in populations that are not obviously vulnerable will help build up herd immunity and is a more realistic way to stop the pandemic, instead of the restrictive lockdowns that have proved economically devastating.
“Never in the history of public health has herd immunity been used as a strategy for responding to an outbreak,” Tedros said. Tedros said that too little was known about immunity to Covid-19 to know if herd immunity is even achievable.