Covid-19 latest: Herd Immunity debate continues! What do WHO, scientists say

Coronavirus COVID-19 tracker: Even as the debate over the herd immunity continues to grow, the World Health Organization has termed the herd immunity as “scientifically and ethically problematic”. However, several scientists have claimed that the Coronavirus pandemic might come to an end sooner if the disease is allowed to spread rapidly among the population provided the elderly and the vulnerable get the much-required shielding, according to an Indian Express report.

A group of prominent scientists has released a declaration. In that declaration, they have expressed “grave concerns” regarding the physical and mental health impacts of the “prevailing Covid-19 policies” implemented around the world. The declaration also recommended “Focussed Protection” based on the concept of herd immunity. Professor at Stanford University Medical School Jay Bhattacharya, Epidemiologist at Oxford University Sunetra Gupta, and professor of medicine at Harvard University Martin Kulldorff have released the declaration. The declaration has received signatures of nearly 9,000 medical and public health scientists, over 22,000 medical practitioners around four lakh other people.

The scientists said in the declaration that the most compassionate approach that balances the risks and benefits of reaching herd immunity, is to allow those who are at minimal risk of death to live their lives normally to build up immunity to the virus through natural infection. At the same time better protection should be given to those who are at highest risk, they said. “We call this Focused Protection. We know that all populations will eventually reach herd immunity — i.e. the point at which the rate of new infections is stable — and that this can be assisted by (but is not dependent upon) a vaccine. Our goal should therefore be to minimize mortality and social harm until we reach herd immunity,” the scientists said in the declaration.

However, WHO Director-General Tedros Adhanom Ghebreyesus has a different view. He said that “herd immunity” has never been used as a strategy for responding to an outbreak, let alone a pandemic in the history of public health. He said that it is scientifically and ethically problematic.

Talking about herd-immunity, the WHO Director-General said that there is not enough knowledge about immunity to Coronavirus. He most of the Coronavirus infected patients generally develop an immune response within the first few weeks. However, it is yet to be ascertained how strong or lasting that immune response is and how it differs for different people. “We have some clues, but we don’t have the complete picture. There have also been some examples of people infected with Covid-19 being infected for a second time,” the WHO Director General said.

Ghebreyesus said that a large number of population in most countries remain susceptible to the Coronavirus. He said that Sero-prevalence surveys around the world indicate that less than 10 per cent of the population have been infected with the Covid19 virus in most countries. Ghebreyesus said if the coronavirus is allowed to circulate unchecked, it cause more infections and deaths.

The WHO Director General said 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. Herd immunity against measles requires around 95 per cent of a population to be vaccinated and the remaining 5 per cent will be protected by the fact that measles will not spread among those who are vaccinated, he said. “For polio, the threshold is about 80 per cent. In other words, herd immunity is achieved by protecting people from a virus, not by exposing them to it,” the WHO Director-General asserted, as per IE report.