'Delta variant 8 times less sensitive to Covid vaccine antibodies'

New Delhi: A recent collaborative research study on the B.1.617.2 Delta variant on over 100 health care workers (HCWs) across three centres in Delhi including Sir Ganga Ram Hospital has revealed that in vitro, the variant is less sensitive to neutralising antibodies in sera from recovered individuals, with higher replication efficiency as compared to the Alpha variant.

The study was done by researchers from Cambridge University's Institute of Therapeutic Immunology & Infectious Disease, India's National Centre for Disease Control, Imperial College London, doctors from Sir Ganga Ram Hospital, and others. The study is available on-line as a non-peer reviewed preprint version in research in RESEARCH SQUARE.

Delta variant shows 8 fold reduced sensitivity to vaccine elicited antibodies. Mutant has enhanced spike proteins for attachment to the lung epithelial cells which has provided it much higher capacity to infect many more people than the Wuhan strain.

In an analysis of vaccine breakthrough in over 100 healthcare workers across three centers in India, the B.1.617.2 Delta variant not

only dominates vaccine-breakthrough infections with higher respiratory viral loads compared to non-delta infections (Ct value of 16.5 versus19), but also generates greater transmission between fully vaccinated HCW as compared to other variants B.1.1.7 or B.1.617.1.