INSACOG or India’s Genome Consortium backtracked its advice a week ago that additional shots may be considered for people above the age of 40 in order to deal with a possible Omicron threat in the country.
According to a senior member of the of the organization who wished to remain anonymous, the decision was made based on certain emerging data and also amidst concerns that there might be issues about possible ADE (Antibody dependent enhancement) and viral priming occurrences and issues with regarding the Omicron variant.
Typically, booster shots are jabs given to ramp up the number of antibodies provided by vaccines that wane over a period of time.
It was reported that in a bulletin dated November 29, the genome sequencing body had said: “Vaccination of all remaining unvaccinated at-risk people and consideration of a booster dose for those 40 years of age and over, first targeting the most high-risk/high-exposure may be considered, since low levels of neutralizing anti-bodies from current vaccines are unlikely to be sufficient to neutralize Omicron.”
Risk of severe disease
“Vaccination of all remaining unvaccinated at-risk people and consideration of a booster dose for those 40 years of age and over, first targeting the most high-risk/high-exposure may be considered, since low levels of neutralising anti-bodies from current vaccines are unlikely to be sufficient to neutralise Omicron, though risk of severe disease is still likely to be reduced,” the release notes and added that “..population immunity and vaccine-induced immunity may not sufficiently block its propagation”.
Indian studies are already showing evidence that real world effectiveness of both Covaxin and Covishield was lower than reported in clinical trials and that immunising anti-bodies reduced over time, creating opportunities for breakthrough infections and sometimes reinfections.
A study by the Translational Health Science Institute, Faridabad, published last week in the Lancet Infectious Diseases, reported that two shots of Covishield gave 63% protection against symptomatic SARS-CoV-2 infection and 85% protection against moderate or severe disease. A similar study for Covaxin isn’t yet available.
Anurag Agrawal, Director, CSIR-IGIB and who is part of the INSACOG, said these specific recommendations only reflected the World Health Organisation’s views on the same about first vaccinating the unvaccinated and then considering boosters based on evidence. “The INSACOG isn’t an advisory body.
The evidence right now about potential immune escape, vaccination breakthroughs and possible booster need, is all that we have conveyed. In a few more weeks we’ll have better information [from South Africa] on whether Omicron is linked to increased disease severity” he told The Hindu.
The U.S. and the U.K. have approved booster doses for all adults, six months after the completion of their second dose. A recent study in Israel found that immunity against infection dipped noticeably in the six months after two doses of the Pfizer/BioNTech vaccine.
Compared to people who got only two doses five months prior, those who got three doses of the vaccine had 93% lower risk of COVID-19-related hospitalisation, 92% lower risk of severe disease and 81% lower risk of COVID-19-related death.
Vaccine effectiveness appeared consistent across sexes and age groups (ages 40-69 and 70+) and number of co-morbidities.
India has so far administered 125 crore doses with about two thirds being first doses. Only a third of Indians have been fully vaccinated and about 60% have got at least one dose.
Since the week October 9-15, the number of second doses has been exceeding the first dose and the Government is far short of meeting its stated target of vaccinating all adults — 94 crore — by the year end.