Dr Soumya Swaminathan, chief scientist at the World Health Organisation (WHO), has warned against leaning on the herd immunity approach to fight COVID-19, pointing the ‘huge costs’ to be paid.

In an interview with NDTV, she said that the global health body has always been clear about its stance on herd immunity. Instead, the focus should be on achieving, “Hybrid immunity is the strongest immunity we can have at the moment – Hybrid is when one has been infected with omicron and has also got the vaccine doses,” she explained.

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On its website, the WHO defines herd immunity as the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection.

“WHO supports achieving ‘herd immunity’ through vaccination, not by allowing a disease to spread through any segment of the population, as this would result in unnecessary cases and deaths,” it said. 

Dr Swaminathan also spoke about the omicron sub-lineage BA.2, termed ‘stealth omicron’ by some scientists for its reportedly higher transmissibility. She acknowledged that it is more potent than BA.1 and has taken several countries, particularly India and Denmark, in its grip.

Also Read: ‘Stealth omicron’ & COVID: Has the BA.2 sublineage been reported in India?

It is still too early to comment on omicron since it was only detected about two months ago, she said. “Two months is too little time to know if it causes reinfection and how it affects long term immunity. We saw some studies where the blood of patients who recovered from the new variant helped with Delta infection but we don’t know if that will be true for future variants.”

Further, while antibodies from COVID vaccines may not be as likely to neutralise the new variant as they were with the earlier ones, there is massive evidence to suggest they bring down case severity and death rate among patients.

Also Read: Omicron is less severe as it spares the lungs, studies suggest

“The vaccines that we are using for protection in terms of reducing hospitalisations and deaths are working very well. All of them help us. The elderly and vulnerable are much better protected now. It shows that the vaccines are effective and a good defence mechanism,” she told NDTV.