Vaccines protect against severe forms of Covid-19 linked to the Delta variant, according to new US study
Fully vaccinated people are 11 times less likely to die from Covid and 10 times less likely to be hospitalized since the contagious Delta variant became the main strain of the virus in the United States, US health officials said on Friday.
Data from three articles published 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 vaccines against severe forms of the virus.
“As we have shown, vaccination works”
This announcement comes the day after the unveiling of President Joe Biden’s new muscular strategy to tackle the Covid-19 epidemic. This includes in particular a decree requiring employees of large American companies to be vaccinated or undergo a weekly screening test.
“As we have shown, study after study, vaccination works,” said CDC director Rochelle Walenksy at a press conference.
The first study analyzed hundreds of thousands of cases of Covid-19 in 13 US jurisdictions over the period from April 4 to June 19, before the Delta variant proliferated, and compared them to cases of contamination from June 20. to July 17.
Between these two periods, the risk of a fully vaccinated person being infected with Covid-19 compared to an unvaccinated person increased slightly, from 11.1 times less likely to be infected to 4.5 times .
Protection against hospitalization and death remained stable, but declined more for people 65 years of age and older than for groups of younger individuals.
Health officials are assessing the need for a third dose, and older people are likely to be the first to receive it when the Biden administration launches its recall campaign on September 20.
Moderna more effective against hospitalizations
One of the studies, which analyzed the effectiveness of different vaccines between June and August in more than 400 American hospitals and health centers, determined that Moderna’s serum was the most effective against hospitalizations (95%), come then those of Pfizer (80%), and Johnson & Johnson (60%).
It is not yet entirely clear why Moderna’s vaccine appeared to confer higher protection than Pfizer’s when the Delta variant became the main strain of the virus.
This could be related in particular to its higher dosage of 100 micrograms against 30 micrograms, or to the longer interval between the first and the second injection (four weeks against three for the Pfizer), which could, according to specialists, create a stronger immune response.