How effective is the vaccine against Omicron?
A new American study claims that during the wave caused by the new variant, the severe forms of the virus were countered very satisfactorily.
From August 26, 2021 to January 5, 2022, the Centers for Disease Control and Prevention (CDC) in the United States reviewed data from more than 300,000 emergency room visits, urgent care clinics and hospitalizations in 10 US states.
The verdict, announced on Friday, indicates that vaccines and booster doses against Covid-19 continued to have very high efficacy against severe cases of the disease.
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During the period in which the Delta variant was dominant, vaccine efficacy against hospitalizations due to Covid-19 was 90% between 14 and 179 days after the second dose of a vaccine.
It fell to 81% over 180 days after the second dose and rose to 94% 14 or more days after the third.
Once Omicron became dominant, vaccine efficacy against hospitalizations between 14 and 179 days after the second dose was estimated at 81%;
it was 57% after more than 180 days after the second dose, and 90% 14 days or more after the third.
A second study, based on data from 25 US states and local jurisdictions, shows that vaccine effectiveness against infections rose from 93%, before Delta, to about 80% once Delta became dominant;
but death protection remained stable - and high - at 94%.
Drop to 68% effectiveness against infections
Efficacy against infections dropped to 68% with Omicron.
The authors were unable to derive an estimate of vaccine protection against death during Omicron due to a delay in recording information, but scientists widely expect it to remain. very high.
The study also shows that while deaths among fully vaccinated people increased markedly during the Delta wave (more than 20,000 people between July and November), unvaccinated people were 16 times more likely to die during the same period.
Protection was even greater for people who received a booster dose.
Between October and November, unvaccinated people were 50 times more likely to die from Covid than vaccinated people who received a booster.
