Herd Immunity To Fight Covid "Foolish Idea": WHO Chief Scientist To NDTV

The idea of attaining herd immunity through natural infection to fight against Covid is "foolish" as there are huge costs to be paid, Chief Scientist at the World Health Organisation Dr Soumya Swaminathan told NDTV today, adding that the WHO has always maintained this stand. About the new Omicron sub-variant, she said that BA.2 is more potent than BA.1 and its transmission is more than other sub-variants. It's taking a grip in some countries, especially India and Denmark, she added. 

Dr Swaminathan said that the global health body can not yet comment on the impact of Omicron as it's a relatively new variant and studies are still going on to determine if it can cause reinfection and how it affects long term immunity. "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," she said. 

On how current vaccines against Covid are responding to Omicron, she said that lab level studies show antibodies are less likely to neutralise the new variant, even less than the Delta variant which was already less responsive to the vaccine than the previous variants that were taken into account while developing the vaccines. However, the good news is that clinical data shows fewer cases of deaths and severe disease in vaccinated patients. There's no need to be concerned about whether the current vaccines work on the Omicron strain, she said.

"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 said, adding that we should not take into account just antibody response but also carefully look at clinical data and study other factors like T-cell response. 

"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 said.

On whether there will be more mutations, she said that it's an RNA virus and it's natural for it to keep mutating.

The WHO has been discussing a universal vaccine that works against all variants of the virus, she informed. "A pan-coronavirus vaccine or pan-SARS vaccine is the Holy Grail and would be ideal. Scientifically, it is plausible and possible, but all these are being worked on and we will have to wait and see," she said and compared it with efforts to create a universal influenza vaccine. Currently, the influenza shot has to be modified every year because of new strains.

Heterologous booster shots (when a different vaccine is used for a booster shot than the one taken earlier) and intranasal vaccine to provide local mucosal immunity are also being explored, she said.

Dr Swaminathan stressed studying local data to make decisions on booster shots. "It is ideal to have ones own data coming from one's own studies. It is not ideal or possible to take another country's data and try to work out one's strategy. Having local scientific research and data is crucial," she said. 

WHO has been clear on the need to prioritise some groups to start the booster vaccines. Increasing age and underlying comorbidities are risk factors, she said. 

The immune system wanes as you get older and that's why it needs additional stimulus to raise immune levels, she said when asked why senior citizens with comorbidities are prioritised for booster shots when many young people also live with comorbidities. 

India has done a commendable job in vaccinating a large population, given its size and complexities involved in getting people vaccinated, she said. 

On whether Covid pills that can be administered orally are working, she confirmed that they indeed are working against all variants. Monoclonal antibody treatments, however, don't seem to be working, she added.