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COVID-19 | Genome consortium advises booster shots

A vendor sells face masks in Bengaluru on December 2, 2021. India on December 2, 2021 confirmed its first cases of the Omicron variant in two men in Karnataka.   | Photo Credit: AP

The Indian SARS-COV-2 genome consortium (INSACOG), which confirmed the presence of the Omicron variant, in an advisory made public on Thursday, has recommended that boosters (or third doses) “be considered” in those above 40.

Decisions on vaccination are vetted by the National Technical Advisory Group on Immunisation (NTAGI) and the INSACOG is a body of 10 labs with expertise in genome sequencing and isn’t an advisory body. However, this is the first time that an official body in India has broached the subject of booster doses.

Also read | Doctor, South African national India’s first two cases of Omicron

The advisory was prepared on Monday and before it confirmed the presence of the Omicron variant in India.

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.

Explained | Understanding the Omicron variant of coronavirus

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.

Also read | Omicron may have been in Karnataka much earlier: Experts

Consistent effectiveness

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.


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Printable version | Jan 22, 2022 11:47:43 AM | https://www.thehindu.com/news/national/covid-19-genome-consortium-insacog-advises-booster-doses-be-considered/article37813524.ece

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