New Delhi, Oct 13 – India may require the third dose of Covid vaccine by the middle of next year, said eminent scientist and biochemist Prof G. Padmanaban, as breakthrough cases even after full vaccination have been prevalent, even though mostly mild.
Prof. Padmanaban, who is Chancellor of Central University of Tamil Nadu and a Padma Bhushan recipient, said that his opinion of a third dose is based on “scientific understanding”.
“In an infection by the Delta variant, which is widespread, there is a six-eight fold drop in the potential of antisera from vaccines to neutralise the variant compared to the wild type (used for vaccination- spike or whole virus).
“Nobody still has a clear answer to how long the protective antibodies will last, it has been variably estimated to be between six months and one year. If the virus has not weakened by itself, by that time, there is possibility for a re-infection,” he said.
As scientists’ understanding of cell-mediated protection (cellular immunity and humoral immunity) is still evolving in the case of Covid, “a third dose (sometime mid to late next year) by mix and match, also gives an opportunity to give a different vaccine against the variant,” he noted.
