While the European Medicines Agency (EMA) and the Haute Autorité de Santé (HAS) have given the green light to the use of new bivalent vaccines against Covid-19, in particular within the framework of the vaccination campaign which began on October 3, the World Health Organization (WHO) believes that data is currently lacking.
These new vaccines are no less effective than the previous ones, but it cannot be said that they are more effective and therefore a vaccination or a booster should not be postponed on the pretext of waiting for the availability of these new versions.
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This concerns the four mRNA vaccines developed by the Pfizer / BioNTech and Moderna groups, new generation vaccines that include the BA.1 or BA.4/5 subvariants of Omicron in combination with the original virus.
However, according to the group of experts who advise the WHO on vaccination, these vaccines are likely to offer only a
"tiny additional benefit"
compared to previous vaccines.
“A relatively modest effect”
Indeed, there would have been no clinical data to demonstrate the efficacy of these vaccines on humans.
In a statement, the Strategic Advisory Group of Experts (SAGE) said that
“currently available data are not sufficient to support making a recommendation in favor of booster doses containing bivalent variants”
compared to vaccines based on on the original virus.
SAGE executive secretary Joachim Hombach pointed out that experts had found that bivalent vaccines had shown
“slightly greater neutralization of the Omicron variant”
.
"It's a relatively modest effect that we can see in the lab
," he said.
“What we cannot do is associate these laboratory measures with an increase in protection”
because the data that would demonstrate this increased effectiveness are not yet available.
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Getting vaccinated is essential
"Because our recommendations have to be really evidence-based, we can't make a statement in favor of these vaccines
," Dr. Hombach said.
He adds that
“these vaccines are fine, but what is much more important”
for protection against Covid-19
“is that you get vaccinated”
, regardless of whether the product has been modified to target sub- Omicron variants or not.
And this applies equally well to the first or the second recall depending on the latter.
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615 million confirmed cases
As of October 2, more than 615 million confirmed cases of Covid-19 and more than 6.5 million deaths have been reported to WHO worldwide.
The Omicron variant accounted for 99.9% of virus samples collected over the past 30 days that were sequenced and uploaded to the global science initiative GISAID (Global Initiative on Sharing Avian Influenza Data).
Of these, the BA.5 group of Omicron subvariants remains overall dominant at 81%, followed by BA.4 at 8% and BA.2 at 3%.
