Covid-19: Vaccine efficacy issue may dent fight against variants

A woman gets vaccinated against Covid-19 at Nair hospital on July 14. Pic/Ashish Raje

Will vaccines work on the new novel Coronavirus variants Kappa and Lambda? Health experts have raised concerns about the efficacy of vaccines against the variants and a few feel that there is a need to intensify testing and modify vaccines accordingly. The unvaccinated may be at risk of getting infected faster.

mid-day reported on the steps to take against the new variants in its July 21 edition.

"The efficacy of any vaccine will need monitoring and modifications within a short time based on the variants," said Subhash Hira, professor of Global Health, University of Washington-Seattle. Kappa and Lambda are currently Variants of Interest.

"As per studies, Kappa and Lambda are considered to be more transmissible, can cause more severe disease, and decrease vaccine effectiveness," said Dr Hira.

"The emergence of newer mutant strains is a serious cause for concern. Researchers need to find out their source. Genomic study of strains is essential to identify variants," said Dr Ketan Vagholkar, professor of surgery at D Y Patil Medical College.

Dr. Wiqar Shaikh, professor of Medicine, Grant Medical College and Sir JJ Group of Hospitals, said that only herd immunity, achieved naturally or through vaccines, can end the pandemic. He said that the current Covid-19 vaccines have been found to be effective against the original Covid-19 virus. But that may not be the case against its variants.

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Dr Shaikh cited comments by the US's Centre for Disease Control (CDC), an article in the American journal, JAMA, and opinions of the Johns Hopkins Hospital in the USA - which pointed towards lesser efficacy of vaccines against Covid-19 variants.

Alarming studies
Dr. Shaikh is alarmed by a February 17 study in the New England Journal of Medicine (NEJM) from South Africa in which two doses of the Pfizer-BioNTech vaccine against the Beta variant were found to have two-thirds less efficacy than against the original Covid virus. A May 20 study in the journal, Dr Shaikh said, is even more shocking - in South Africa, the efficacy of the Oxford-AstraZeneca vaccine against the Beta variant was only 10.4 per cent. A February 12 study from South Africa in the journal, medRxiv, claimed that the Oxford-AstraZeneca vaccine did not protect against the Beta variant.

A June 30 study in Forbes collected data from Lancet, NEJM and Public Health England (PHE) regarding the efficacy of Pfizer-BioNTech, Moderna, Johnson and Johnson and Oxford-AstraZeneca vaccines. It found that all showed less effectiveness against variants. He added that a similar problem has been found in the "monoclonal antibody cocktail" currently being used against Covid. There are several such cocktails available in the market.

He quoted JAMA which said that "the challenge for the world when modifying a vaccine is which variant to pick and how often does it mutate". JAMA also said that "the need to deploy modified vaccines targeting new variants will complicate an already rocky rollout of Covid-19 vaccines".

Dr. Shaikh is worried that Covid-19 vaccines may end up as annual jabs around the world and added that Pfizer has already announced that the efficacy of its vaccine will not last more than six months and that booster doses will definitely be required.