Original Covid vaccine still valid as variants continue to emerge, says ex-WHO chief scientist

Bivalent vaccines (made with two strains of Covid) may be marginally better, but the original vaccines are good enough, the expert said

With rising concerns over the Covid-19 surge in China and with India implementing new curbs against the virus, former WHO chief scientist Soumya Swaminathan has said that the original vaccine as a third dose will give a sufficient boost against the virus, as against the bivalent vaccines.

"The bivalent vaccines may be marginally superior to the original vaccine when used as a booster but a third dose of the original vaccine also provides a good boost and should be used in all countries where the bivalent vaccines are not available," Dr Swaminathan told The Indian Express in an interview.

A bivalent vaccine is that which is developed using two strains of coronavirus.

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Dr Swaminathan said that despite the drop in its effectiveness against Omicron variants, vaccines that were made using the original strain in Wuhan are still efficient in preventing any severe infection or death. While the requirement of a new booster is still unclear, two primary doses and one booster should suffice for now, she said.

"Luckily for us, the vaccines that were developed using the original Wuhan strain of the virus, are still good at preventing severe disease and death, even though their effectiveness against infection dropped with the Omicron VOC"

She added that the emergence of new variants will always be a matter of concern as the virus is “constantly adapting", but the variants that are emerging now are similar to those that are already seen in other parts of the world and the label of “Variant of Concern” will be given only if any new variant is more transmissible and severe than the ones already circulating.

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Regarding the need for the fourth dose of vaccine, she told the publication that the factors like age, type of vaccine, health conditions etc influence such decisons. She also added that the introduction of nasal vaccines may confer great benefit if used in the form of a booster but “carefully performed studies” are needed in the field.

Speaking on the trajectory of Covid-19 going forward, Dr Swaminathan predicted a gradual demotion of the infection to an endemic. However, she also warned that deaths and diseases may continue. She hailed vaccination as a “key and powerful preventive tool”, and highlighted the “inequity” of access to vaccines globally.