“There is consistent evidence that Omicron has a substantial growth advantage over Delta. It is spreading significantly faster than the Delta variant in countries with documented community transmission, with a doubling time between 1.5–3 days,” said WHO’s technical brief to member-countries. The saving grace so far has been Omicron’s lower virulence even though its spread underlines the need for measures like masks, sanitisation and avoidance of large gatherings along with vaccination.
The UN health agency said it remains uncertain to what extent the observed rapid growth rate can be attributed to immune evasion, intrinsic increased transmissibility or a combination of both. Preliminary data also suggests there is a reduction in neutralising titres against Omicron in those who have received a primary vaccination series or who have had prior SARS-CoV-2 infection, which may suggest a level of humoral immune evasion. Humoral immunity is the process of adaptive immunity manifested by the production of antibodies that develops in bone marrow. The number of people infected with the Delta variant in the UK were found to be doubling every 11 days, according to a study conducted by the Imperial College of London based on analysis of swab tests taken between May 20 and June 7. “Given current available data, it is likely that Omicron will outpace Delta where community transmission occurs,” the latest WHO update said.
In India, while overall Covid-19 cases continue to be below 10,000 for around 20 days, health authorities have cautioned against complacency highlighting examples of countries like the UK and France that are witnessing a surge powered by Omicron despite high-vaccination rate and exposure to the Delta variant.
A total of 7145 new Covid-19 cases were recorded from across the country on Friday. Active caseload currently stands at 84,565 cases. This includes Omicron-infected cases but Delta continues to be the dominant variant so far, according to officials.
While some studies from the UK show that the risk of reinfection from Omicron is higher than Delta and there are no signs of the infection being milder than Delta, the UN health agency maintained there are still limited data on the clinical severity of Omicron. “More data are needed to understand the severity profile and how severity is impacted by vaccination and pre-existing immunity. Hospitalisations in the UK and South Africa continue to rise, and given rapidly increasing case counts, it is possible that many healthcare systems may become quickly overwhelmed,” WHO said.
As of December 16, the Omicron variant has been identified in 89 countries across all six WHO regions.