A clinical model released this Friday suggests that the effectiveness of booster vaccines against covid-19 caused by low omicron compared to the delta variant, although they still offer high protection against the disease.
Researchers from Imperial College London (United Kingdom) also analyzed the risk of reinfection with omicron in another study and found that it is 5.4 times higher than with delta, suggesting that the protection offered by a previous infection against the new variant could be less than 19%.
Regarding additional punctures, the aforementioned clinical model estimates that after two doses and the booster dose there is a 4.5-fold reduction in the levels of neutralizing antibodies against omicron compared to delta.
For this work, they analyzed three scenarios and, in the worst case, they assumed that the efficacy of the vaccines declines at the same rate after the booster shot as after the two doses.
In this context, they found that the effectiveness of the preparations to avoid hospitalizations two months after the reinforcement was administered they can fall from the 96.85% offered by delta to 80.1% for omicron.
Increase in deaths
The researchers indicate that these percentages translate into a “high degree of individual protection”, but warn that the new variant is likely to cause a large number of infections and `may seriously affect the capacity of health systems worldwide.
“While the degree of decline (of efficacy) against severe disease, which requires hospitalization, is less than against mild, even small reductions in protection can cause significant increases in hospital admissions and deaths, especially in high-risk groups, “they observed in a statement.
They also specify that although these results are still surrounded by uncertainty, given the recent appearance of omicron, they suggest that it will be need to develop specific vaccines for this variant and / or booster doses to “restore protection”.
However, they note that there is now “more evidence” on how omicron can “very substantially evade” the “immunity that both previous infections and vaccines grant.”
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“This level of immune evasion means that omicron represents a significant and imminent threat to public health“, emphasizes the expert Neil Ferguson, of the Imperial College.
His colleague Azra Ghani adds that the ability to “quantify” the risk of reinfection and the efficacy of the preparations against omicron is “essential” to make projections about their “future trajectory” and “impact” in immunization campaigns.
Reference-www.elperiodico.com