Vaccines maybe 8 times less effective against Delta Covid-19 variant: Study

A new study conducted at Delhi's Sir Ganga Ram hospital has shown the Delta variant of SARS-CoV-2 has eight-fold reduced sensitivity to vaccine-elicited antibodies. This could potentially mean the COVID-19 vaccines are eight times less effective against the Delta variant of SARS-CoV-2, the virus which causes COVID-19 infection, compared to the Wuhan variant.

"Dominance of the Delta variant in India has been most likely driven by a combination of evasion of neutralising antibodies in previously infected individuals and increased virus infectivity," claimed the study conducted by Research Square.

The study also claimed the Delta variant, also known as B.1.617.2, is less sensitive to neutralising antibodies that are found in the bodies of recovered COVID-19 patients.

"Re-infection and increased transmissibility played a significant role in the spread of the Delta variant of Covid-19," noted the study. The study found that transmission clusters in vaccinated healthcare workers were associated with the Delta variant of the coronavirus.

"In an analysis of vaccine breakthrough in over 100 healthcare workers (HCW) across three centres in India, 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 HCW as compared to B.1.1.7 or B.1.617.1," the study noted. The study is yet to be submitted for peer review.

What is the Delta variant of SARS-CoV-2?

The Delta variant of the coronavirus was first uncovered in Maharashtra late last year. Since then the variant has spread all across India. This variant has replaced the Alpha variant as the dominant strain of SARS-CoV-2 in India.

According to the study, the Delta variant of the coronavirus has enhanced spike proteins, which enables it to attach itself to the lung epithelial cells. Hence, it is able to infect a lot more people than the original Wuhan strain of the virus.

The study also claimed this variant is performing higher replication in primary airway cells of human bodies. "Increased replication could be responsible for generating greater numbers of virus particles, or the particles themselves could be more likely to lead to a productive infection," noted the study.

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