Dimapur, Dec. 22 (EMN): Amid rapid spread of Omicron, labelled as a variant of concern, across the world including India, the department of Health and Family Welfare, Nagaland, has provided details about the variant and measures needed to be taken to prevent its spread.
Transmissibility
- Omicron is at least three times more transmissible than the delta variant (MoHFW)
- has substantial growth advantage over delta (WHO)
- In countries with community transmission by Omicron, doubling time is between 1.5-3 days (WHO)
- Omicron is spreading rapidly in countries even with high level of population immunity (WHO)
- rate of transmission from an index case. Secondary attack rate of 21.6% as compared to 10.7 % by Delta (UK study)
Disease severity
- Data on clinical severity is still evolving as there is a time lag between increase in cases and hospitalisations or deaths.
- Hospitalisations in UK and South Africa continue to rise daily- countries most affected by Omicron.
- “It is too early to conclude if Omicron is more or less severe than other VOCs. However, early data suggest that the severity may be potentially lower than for the delta variant and even if this is the case, it is expected that hospitalisations will increase as a result of significant increases in transmission. More hospitalizations will put a burden on health systems and lead to more deaths, particularly with short doubling” (WHO)
Impact on diagnostics
- Available RT PCR kits and rapid antigen tests is effective in detecting Omicron as per available evidence. Further genomic sequencing will follow up as necessary.
Effect on vaccines
- Reinfection by Omicron appears to be higher than with other VOCs (South Africa/UK Study)
- Preliminary data suggest a fall in neutralising titres against Omicron
- Two doses of available vaccines appear to have reduced effectiveness against omicron on infection, symptomatic disease, and hospitalisation (WHO)
- South Africa reported vaccine effectiveness of the Pfizer BioNTech-Comirnaty vaccine of 33% against infection and 70% against hospitalisation (Preliminary data)
- humoral immune response may be reduced, initial data indicates 70% of Omicron epitopes may not be affected by T- Cell recognition which will mean cellular mediated protection against severe disease may be preserved.
- Vaccines remain the most effective intervention against severe disease and death– against circulating VOC and possibly against Omicron.
