New Delhi: Fully vaccinated people over 40 years of age, especially those at higher risk, should get booster shots against Covid-19, a consortium of labs that monitors genomic variations in the SARS-CoV-2 has said.
The recommendation comes from the Indian SARS-CoV-2 Genomics Consortium (INSACOG), a joint initiative of the Union Health and Family Welfare Ministry, and Department of Biotechnology, with the Council for Scientific & Industrial Research and the Indian Council of Medical Research (ICMR).
The INSACOG statement, part of its weekly bulletin dated 29 November, came soon after the first two known cases of the Omicron variant in India were detected in Karnataka. Both patients — a 46-year-old Indian man and a 66-year-old South African national — were fully vaccinated.
Apart from genomic surveillance, monitoring travel, contact tracing of Covid-19 cases, and increased testing, INSACOG has recommended that all remaining unvaccinated people be vaccinated, and fully vaccinated people over 40 years of age — beginning with those who are at highest risk (due to comorbidities) or more likely to be exposed to the virus — be given a booster shot.
With the emergence of the Omicron variant becoming a major cause for concern, experts in many countries are recommending a booster dose. So far, the Indian government’s stance has been to focus on fully vaccinating the entire population.
This is the first time an official body in India has recommended a booster shot for Covid. However, the INSACOG is not an advisory organisation. Any decision regarding India’s vaccination policy will have to be approved by the National Technical Advisory Group on Immunisation in India (NTAGI).
A study published in the Lancet journal Friday showed that at least six vaccines can be safely used as booster shots to be administered to those who have been fully vaccinated with Covishield. However, there is no data available on the safety or effectiveness of using booster shots on people who have been fully vaccinated with Covaxin.
‘Vaccine-induced immunity may not help’
The Delta variant and its derivatives continue to be the main concern in India, INSOCAG noted in its statement, adding that a “fair and effective strategy for detecting and containing entry of Omicron into India is being implemented”.
Based on preliminary data, it added, it is likely that population immunity and vaccine-induced immunity may not sufficiently block propagation of the Omicron variant.
Vinod Scaria, a researcher at the CSIR-Institute of Genomics and Integrative Biology in New Delhi, had said last month that the new variant has as many as 32 mutations — a number of which are linked to immune escape and increased transmissibility.
Although there is no evidence yet to show that the Omicron variant increases the severity of Covid, booster shots should be considered, since low levels of neutralising antibodies from current vaccines are unlikely to be sufficient to neutralise Omicron, the consortium said. However, it added that the “risk of severe disease is still likely to be reduced”.
Apart from 32 mutations seen in the spike protein of the virus, the Omicron variant also sees changes in nucleocapsid protein — which encapsulates and protects the viral genome — which increase infectivity, as seen in the Delta variant, it added.
INSACOG also said that preliminary evidence suggests Omicron may increase reinfection risk, which “is expected from the structural changes due to the mutations, and the number of cases of this variant appears to be increasing in almost all provinces in South Africa”.
The mutation spectrum of Omicron is also predictive of high transmissibility, the consortium noted.
(Edited by Gitanjali Das)