Herd Immunity is scientifically and ethically problematic: WHO2 min read . Updated: 13 Oct 2020, 12:26 PM IST
- Seroprevalence surveys suggest that in most countries, less than 10% of the population have been infected with covid-19
NEW DELHI : Strongly refuting the idea of herd immunity to fight covid-19, the World Health Organization (WHO) on Monday said that it has never been used as a strategy to respond to an outbreak in the history of public health, let alone a pandemic.
Labelling herd immunity as 'scientifically and ethically problematic', Tedros Adhanom Ghebreyesus, Director-General at WHO, said that it is achieved by protecting people from a virus, not by exposing them to it.
“There has been some discussion recently about the concept of reaching so-called “herd immunity" by letting the virus spread, Tedros said, adding that herd immunity is a concept used for vaccination, in which a population can be protected from a certain virus if a threshold of vaccination is reached.
Citing examples that herd immunity against measles requires about 95% of a population to be vaccinated, the WHO chief said that the remaining 5% will be protected by the fact that measles will not spread among those who are vaccinated. For polio, the threshold is about 80%.
"First, we don’t know enough about immunity to covid-19. Most people who are infected with the virus that causes covid-19 develop an immune response within the first few weeks, but we don’t know how strong or lasting that immune response is, or how it differs for different people. We have some clues, but we don’t have the complete picture," said Tedros.
"There have also been some examples of people infected with covid-19 being infected for a second time. Second, the vast majority of people in most countries remain susceptible to this virus," he said.
Seroprevalence surveys suggest that in most countries, less than 10% of the population have been infected with the covid-19 virus.
Letting the virus circulate unchecked therefore means allowing unnecessary infections, suffering and death, the WHO maintained.
Citing data from across the world, the WHO said, although older people and those with underlying conditions are most at risk of severe disease and death, they are not the only ones at risk. People of all ages have died.
“Third, we’re only beginning to understand the long-term health impacts among people with covid-19," said Tedros adding that a dangerous virus that we don’t fully understand to run free is simply unethical. It’s not an option.
WHO maintained that there are several options and there are many things that countries can do and are doing to control transmission and save lives.
“It’s not a choice between letting the virus run free and shutting down our societies. This virus transmits mainly between close contacts and causes outbreaks that can be controlled by implementing targeted measures," Tedros said.
The WHO recommended to prevent amplifying events, protecting the vulnerable, empower, educate and engage communities and persist with the same tools that the apex global public health agency has been advocating since day one: find, isolate, test and care for cases, and trace and quarantine their contacts.
The WHO chief mentioned about digital technologies including those being used in India that are helping to make these tried-and-tested public health tools even more effective, such as mobile applications to support contact tracing efforts.
“The Aarogya Setu app from India has been downloaded by 150 million users, and has helped city public health departments to identify areas where clusters could be anticipated and expand testing in a targeted way," said Tedros.
Germany’s Corona-Warn app has been used to transmit 1.2 million test results from labs to users in its first 100 days, he said.