COVID vaccines could be 8 times less effective against Delta variant: Study
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New Delhi: The Delta variant of the Covid-19 virus shows eight-fold approximately reduced sensitivity to vaccine-elicited antibodies compared to the Wuhan strain, revealed a recent study on the B.1.617.2 Delta variant. The study found that the variant has a much higher capacity to infect more people than the Wuhan strain.
As per a report by news agency PTI, the study was conducted on more than 100 healthcare workers at three centres in India, including Delhi's Sir Ganga Ram Hospital.
The 'Sars-Cov-2 B.1.617.2 Deltavariant Emergence and Vaccine Breakthrough: Collaborative Study' from India was conducted along with scientists from the Cambridge Institute of Therapeutic Immunology & Infectious Disease.
"Across all scenarios considered, our results suggest the Delta variant is both more transmissible and better able to evade prior immunity elicited by the previous infection as compared to previously circulating lineages," it said, as per the PTI report.
Meanwhile, the collaborative study stated that the Delta variant is less sensitive to neutralising antibodies in sera from recovered individuals, with higher replication efficiency as compared to the Alpha variant.
The findings of the study also revealed that the Delta variant not only dominates vaccine-breakthrough infections with higher respiratory viral loads compared to non-delta infections but also generates greater transmission between fully vaccinated healthcare workers, as compared to other variants B.1.1.7 (Alpha variant) or B.1.617.1 (Kappa variant)."
According to Dr Chand Wattal, Chairperson Institute of Clinical Microbiology & Immunology at Sir Ganga Ram, the reason that the Delta variant is dominant in breakthrough infections is that it has developed spiked proteins in such a manner that it links to cells in a more powerful way. Dr Wattal noted the positive part of this affinity that with vaccines, even if one gets the infection it is likely to be mild to moderate and one is unlikely to die.
The study also states that not only does the Delta variant dominate the vaccine breakthrough infections among the samples, it also leads to higher viral loads and that there is evidence of larger transmission clusters for Delta versus non-Delta infections in these HCWs.
