The coronavirus is mutating, producing new variants and spreading rapidly across the world. While the available vaccines may be able to hold fort against these new variants, it is not yet known how long our immunity will last. Hence, a third booster vaccine or an annual vaccine may be key in protecting people, health experts said on Monday.
"Studies on the durability of our immune responses to the administered vaccines are currently ongoing. Emerging data suggests that there is a likelihood that our immunity may wane over time and given the increasing trend in the emergence of virus variants of concern, there is a high likelihood of booster doses," DrVeena P. Menon, Ph.D, Faculty -In-Charge, Clinical Virology Laboratory, Amrita Institute of Medical Sciences, Kochi, told IANS.
"Yes, the third booster will help since new variants are emerging and we still don't know how long the immunity lasts. Whatever immunity people are gaining with the vaccines, a booster will definitely help. People have suggested an annual vaccination as well," added Dr Suresh Kumar D., Consultant, Infectious Diseases Specialist at Apollo Hospitals Chennai.
However, it remains to be seen when it would be most appropriate to administer the third booster, Menon said.
"Most of the current vaccines, including Oxford- AstraZeneca vaccine, are covering well against the UK variant. But it has done poorly against the South African mutant. The efficacy is 10-15 per cent, which is why South Africa had to return the vaccines. The vaccine is doing reasonably effective against the Brazilian variant with around 40-50 per cent efficacy. Covaxin has not been tested against these variants and there is no research yet on this," Kumar said.
"Changes or mutations in the virus cannot make vaccines completely ineffective. In the event that any of the current vaccines prove to be less effective against one or more variants, it will be possible to change the composition of the vaccines to protect against these variants," DrAlpanaRazdan, VP and Lab Head, Genestrings Diagnostic Centre, New Delhi, told.