(ats) Data from three articles published on Friday by the Centers for Disease Prevention and Control (CDC), the country’s main federal public health agency, unanimously underscore the continued effectiveness of anti-Covid-19 vaccines against severe forms of the virus.
“As we have shown, study after study, vaccination works,” said CDC director Rochelle Walenksy. The first study analyzed hundreds of thousands of cases of Covid-19 in thirteen US jurisdictions over the period from April 4 to June 19, before the Delta proliferated, and compared them to cases of contamination from June 20 to June 17. July.
Between these two periods, the risk of a fully vaccinated person being infected with the coronavirus compared to an unvaccinated person increased slightly, from an 11.1 times less chance of being infected to 4.5 times.
Protection against hospitalization and death remained stable, but declined more for people 65 and older than for younger groups of individuals.
Health authorities are currently assessing the need for a third dose. Seniors are likely to be the first to receive it when the U.S. government launches its recall campaign on September 20.
One of the studies, which analyzed the effectiveness of different vaccines between June and August in more than 400 hospitals and health centers, determined that Moderna’s serum was the most effective against hospitalizations (95%), than that of from Pfizer (80%) and that of Johnson & Johnson (60%).
It is not entirely clear why Moderna’s vaccine appears to confer higher protection than Pfizer, when the Delta variant became the main strain of the virus. This could be related to its higher dosage of 100 micrograms versus 30 micrograms, or the longer interval between the first and second injection (four weeks versus three for Pfizer), which could create a stronger immune response.