Omicron poses big threat in regions with low population immunity: INSACOG

The Indian SARS-CoV-2 Genomic Sequencing Consortium (INSACOG) has said that the threat level posed by Omicron is still very high especially in regions with low population immunity.

New Delhi:“In view of Omicron’s explosive spread potential, the threat level is still very high, especially in regions with low population immunity,” the Indian SARS-CoV-2 Consortium on Genomics (INSACOG) said in its latest bulletin. Referring to available data on Omicron, it said that older non-immune subjects are still likely to be at risk for severe disease, comparable to previous variants.

“Global outbreaks of SARS CoV2 are increasingly shifting from Delta to Omicron. Omicron has a clear growth advantage over Delta, with the highest level of immune escape so far, as well as high intrinsic transmissibility, leading to larger outbreaks than seen with Delta. Estimates of severity of illness associated with Omicron are lower than seen in previous outbreaks,” the INSACOG said.

The difference in severity between Omicron and Delta measured over the same time period is smaller, suggesting that the majority of apparent reduction in severity, compared to previous outbreaks, is because of higher population immunity from previous infections and vaccination.

“Adjusted estimates of the hazard ratio (HR) for hospital attendance for Omicron vs Delta cases in the UK suggest that risk for unvaccinated is only about 25 percent lower for the same period. Importantly, in the UK, individuals who have received at least 2 doses of either AZ/Covishield or mRNA vaccines remained substantially protected against hospitalisation, even if protection against infection was largely lost against the Omicron variant,” it said.

The INSACOG reports genomic surveillance of SARS CoV -2 across the country through sequencing of samples from Sentinel sites and also with detailed State wise district analysis for some states.