A new study conducted on over 100 healthcare workers has found that the Delta variant of COVID-19, first detected in India, is eight times less sensitive to antibodies generated by vaccines in comparison with the original strain of the virus.
The samples were collected from HCWs at three centres Sir Ganga Ram Hospital (SGRH), Indraprastha Apollo Hospital, and Northern Railway Central Hospital.
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It found that the B.1.617.2 Delta variant dominates vaccine-breakthrough infections with higher respiratory viral loads compared to non-Delta infections (Ct value of 16.5 versus 19). It also generates greater transmission among the fully vaccinated HCWs.
According to the World Health Organization, the Delta variant of COVID-19 is now present in nearly 100 countries as per conservative estimates. It has warned that in the coming months the highly transmissible strain will become the dominant variant of the coronavirus globally.
The collaborative study, “Sars-Cov-2 B.1.617.2 Delta Variant Emergence and Vaccine Breakthrough: Collaborative Study”, from India with scientists from Cambridge Institute of Therapeutic Immunology and Infectious Disease is yet to be peer-reviewed.
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Severe disease in fully vaccinated HCWs was rare. However, breakthrough transmission clusters in hospitals associated with the Delta variant are concerning and indicate that infection control measures need to continue in the post-vaccination era, it said.
Based on recent data and the dominance of new infections by this variant, the B.1.167.2 Delta variant appears more transmissible than B.1.1.7 in the UK, it added. It revealed that in vitro, the Delta variant is approximately eight-fold less sensitive to vaccine-elicited antibodies compared to Wuhan-1.
“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 compared to previously circulating lineages,” the findings of the study read.
(With inputs from PTI)
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