Herd immunity occurs when a large portion of a community (the herd) becomes immune to a disease, making the spread of disease from person to person unlikely.
the principle of the so-called “herd immunity” to stem the COVID-19
pandemic is “unethical” and not an option, countries should pursue to defeat the virus, the head of the World Health Organisation Tedros Adhanom Ghebreyesus, has warned.
Herd immunity occurs when a large portion of a community (the herd)
becomes immune to a disease, making the spread of disease from person to person unlikely. As a result, the concept assumes, that through this immunity, the population can be protected from a virus if a threshold of vaccination is reached.
Herd immunity can also be reached when a sufficient number of people in the population have recovered from a disease and have developed antibodies against future infection. There have been arguments that coronavirus should be allowed to spread naturally in the absence of a vaccine.
But Dr Tedros said such an approach is scientifically and ethically problematic. He explained that herd immunity should be achieved by protecting people from the virus, “not by exposing them to it”. “Never in the history of public health has herd immunity been used as
a strategy for responding to an outbreak”, the WHO chief said, in a virtual press briefing.
To obtain herd immunity from measles, for example, about 95 per cent of the population must be vaccinated. However, according to WHO
estimates, less than 10 per cent of the global population has any immunity to the coronavirus
, leaving the vast majority of the world susceptible. But Dr Tedros cautions that letting the virus circulate unchecked, means allowing unnecessary infections, suffering and death.
The WHO chief also reminded that as an uneven pandemic, every country is responding differently, and stressed that outbreaks can be controlled using targeted measures, such as by preventing amplifying events, isolation and testing. “It’s not a choice between letting the virus run free and shutting down our societies,” he declared.
WHO noted that many have harnessed their stay-at-home time to develop
plans, train health workers, increase testing time and capacity, and
improve patient care. And digital technologies are helping to make tried-and-tested public
health tools even more effective, such as better smartphone apps to
support contact tracing efforts.
“We well understand the frustration that many people, communities and governments are feeling as the pandemic drags on, and as cases rise again”, Tedros said. However, there are “no shortcuts, and no silver bullets”, he added.
Only a comprehensive approach, using every tool in the toolbox, has proven effective. “My message to every country now weighing up its options is: you can do it too.”