Delta 8 times less sensitive to vaccine antibodies

Study among hospital staff, including those from Sir Ganga Ram, says inoculated people should not lower their guard

Published: 06th July 2021 08:13 AM  |   Last Updated: 06th July 2021 08:13 AM   |  A+A-

The new study says severe disease in fully vaccinated HCWs is rare but breakthrough infection is a concern and Covid-control measures need to continue

By Express News Service

NEW DELHI: The Delta variant of novel coronavirus is eight times less sensitive to antibodies generated by vaccines as compared to the original strain that came from China’s Wuhan, according to a new study.The study, which was conducted on more than 100 healthcare workers (HCWs) at three centres in India including Sir Ganga Ram Hospital (SGRH), found that the B.1.617.2 Delta variant not only dominates vaccine-breakthrough infections with higher respiratory viral loads compared to non-Delta infections but also generates greater transmission among the fully vaccinated HCWs. 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.

It revealed that in vitro, the Delta variant is approximately eight-fold less sensitive to vaccine-elicited antibodies compared to the original strain from Wuhan.“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 read.

“From this study, it appears that we have miles to go before we sleep in case of Covid-19 pandemic. Mutations are bound to happen if we lower our guard and allow ourselves to fall prey to this virus, giving it an opportunity to multiply,” said Dr Chand Wattal, chairperson of the Institute of Clinical Microbiology and Immunology, SGRH.

“This is a straight eye-opener to the fully vaccinated people that you cannot lower guard in the name of vaccination. The virus is on the prowl, still looking for its prey. This mutant has come back with enhanced spike proteins for attachment to the lung epithelial cells which have provided it with a much higher capacity to infect many more people than the Wuhan strain,” he said.

The data also indicates that the 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 resulting in the second wave, the study said.


Disclaimer : We respect your thoughts and views! But we need to be judicious while moderating your comments. All the comments will be moderated by the editorial. Abstain from posting comments that are obscene, defamatory or inflammatory, and do not indulge in personal attacks. Try to avoid outside hyperlinks inside the comment. Help us delete comments that do not follow these guidelines.

The views expressed in comments published on are those of the comment writers alone. They do not represent the views or opinions of or its staff, nor do they represent the views or opinions of The New Indian Express Group, or any entity of, or affiliated with, The New Indian Express Group. reserves the right to take any or all comments down at any time.

flipboard facebook twitter whatsapp