Almost every week, the British health agency unveils new data on the Omicron variant.
And even during the holiday season.
The UK Health Security Agency (UKHSA) reports this Friday, December 31, the results of a study on the effectiveness of vaccines against the risk of hospitalization.
Last week, she had focused on the symptomatic forms.
These new data are very encouraging.
A symptomatic person after being infected with the Omicron variant has a 68% lower risk of being hospitalized (confidence interval 42 to 82%) if they have received three doses of the vaccine compared to another not vaccinated at all.
It was 89% with Delta.
Note that we do not have separate figures according to the type of vaccine (Pfizer or AstraZeneca for the first two doses then Pfizer or Moderna for the booster dose).
What duration of protection?
Combining this protection with that against symptomatic infection results in an 88% efficacy (78-93% confidence interval) against the risk of hospitalization two weeks after the third dose.
2. Updated Vaccine Effectiveness analysis
Shows that while protection against * infection * starts to wane quickly for Omicron (from 4-9 weeks post-booster đź’‰)
Protection from * hospitalization * is high 88%.
We know from Tcell studies it is unlikely to wane so quickly pic.twitter.com/wXtEzvxRY1
- Meaghan Kall (@kallmemeg) December 31, 2021
A South African study, carried out in November, had resulted in an efficacy against hospitalization of 70% against the Omicron variant with two doses of vaccine, against 93% for Delta.
The impact of a booster dose could not be examined, as the campaign of third injections had not yet started at this time in South Africa.
VIDEO.
Why does the Omicron variant reduce the effectiveness of vaccines?
It remains to be seen how long the protection against the risk of forms will last against Omicron, now dominant in France.
That against the risk of symptomatic infection seems to decrease from the first month, going from 70% to 45% after two months after a booster dose of Pfizer.
"More data is needed to estimate the duration of protection against hospitalization," but "experience with previous variants suggests that it will last longer than protection against symptomatic disease," reassures the British health agency.