Feature: Can Covid vaccines fight the emerging Delta Plus variant, India’s new concern?

(India Today)

Milan Sharma

The Delta Plus variant has been declared a variant of concern in India. While the Centre has said the Covid vaccines are effective against the Delta variant, experts have raised concerns of their effectiveness against the Delta Plus variant.

Scientists from ICMR are working to isolate and culture the Delta Plus variant (AY.1), the new mutation of the dominant Delta variant, at its facilities in NIV Pune to test if the newfound strain can be neutralised with Bharat Biotech’s Covaxin.

Sources have indicated that the serum samples from recovered Covid-19 patients will also be used to check the neutralising potential of the antibodies against the Delta Plus variant.

The Union Health Ministry has said that the vaccines work against the Delta variant. Union health secretary Rajesh Bhushan said, “In India, the two vaccines, Covishield and Covaxin, are effective against the Delta variant. We will be sharing soon the effects of the various vaccines on the Delta variant, antibody titer.”

On the other hand, health experts and virologists have hinted that the Delta Plus variant could evade both vaccine and infection immunity.

Delta Plus resistant to monoclonal antibodies

Experts suggest that the monoclonal antibody treatment being used as a method to fight Covid-19 may not work against the Delta Plus variant. “As per the data available in public domain, monoclonal antibodies might not be effective against the Delta Plus variant. But we need more scientific data to back this claim,” said Dr Rommel Tickoo, director of internal medicine, Max Healthcare.

Efficacy of AstraZeneca against Delta

Recently, health expert and American scientist Eric Feigl-Ding said in a series of tweets that the AstraZeneca vaccine may have limited effectiveness against the Delta variant of SARS-CoV-2. Citing a study, Feigl-Ding said, “The efficacy of AZ [AstraZeneca vaccine] against the Delta variant is not 90% (it’s 60%), Pfizer is 88% in one non-trial study. However, 1 dose of vaccine (both types averaged) is just 33%. And many countries have given just 1 dose.”

Feigl-Ding’s findings have stirred fears of the AstraZeneca vaccine giving little protection against the newly detected Delta Plus variants. WHO has said the Delta variant has become dominant in the world.

WHO on reduced vaccine efficacy

When asked how much of a threat the Delta variant could be in countries that are vaccinating their populations, Dr Maria Van Kerkhove of the WHO said, “The Delta variant is of great concern to us because its spreading across the world. We know that there are 92 countries where the Delta variant is circulating, 80 countries have the B1.617.2 and an additional 12 countries have B.167 but they haven’t further sub-typed it. We don’t know the sub-lineage that is circulating there. This lineage has increased transmissibility more than the Alpha variant (B117).”

“In terms of vaccine effectiveness, we know that for all the variants of concerns, including the Delta variant, the vaccines remain effective against severe disease and death, which is a very good sign. But we need two doses to be administered to have the full level of protection. We do see reduced efficacy with one dose,” she said.

India has reported 21 cases of the Delta Plus in Maharashtra, 2 in Karnataka, 2 in Kerala and 5 cases in Madhya Pradesh. The Delta Plus variant has now been classified as a variant of concern in India by the Union Health Ministry and these states have been told to take up immediate containment measures, enhance testing, tracking and vaccinations. — Courtesy India Today

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