Pfizer Vaccine Less Effective Than Moderna Vaccine Against Delta Variant?

Researchers from the American Federation Clinic Mayo showed it The Pfizer vaccine will be less effective againstalternate delta From our moderator. The report of this study was published on August 8 on the platform MedRxivHowever, the results have not yet been confirmed.

Only 42% efficacy against the delta variant

To conduct this study, the team of scientists analyzed data from 50,000 vaccinated and unvaccinated patients During the period from January to July 2021, corresponding to the deployment of the alpha variant (or English), then the delta variant (or Indian).

Notice that first RNA messenger vaccine It was world wide Very effective against the alpha variant Effectiveness: 86% against infection for Modena, 76% for Pfizer, and 92% and 85%, respectively, against the risk of hospitalization.

On the other hand, With the advent of the delta variableThe results are not the same at all. In July, there was only one Pfizer vaccine 42% effectiveness against infection (But 75% against hospitalization is the same), while Moderna’s vaccine remains effective at 76%.

The results should be taken with caution

This study can revive lively debates about it Vaccine efficacyHowever, the researchers point out that this data needs further investigation and confirmation. Several reasons could explain this difference in efficacy between the two vaccines, But it relies on the same technology. Venky Soundararajan, lead author of the study, explains:

Based on the data we have so far, this is a file combination of workers. It is very likely that the Moderna vaccine is more effective than the Pfizer vaccine in regions where Delta is the dominant strain, and The Pfizer vaccine appears to be less well toleratedAnd

The difference in dose between the two vaccines could also explain these results: Moderna is more powerful than Pfizer.

But epidemiologist Mircea Sofonia points out The serological status of the patients was not taken into account In this study:This means that in the unvaccinated group, it cannot be ruled out that some have been in contact with the virus previously and thus [déjà] developed immunity”, Confirms.

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