Covid-19: vaccines protect well against serious forms linked to the Delta variant – archyde

Fully vaccinated people face an eleven times lower risk of dying from Covid-19, and ten times lower of being hospitalized since the contagious Delta variant became the strain of the virus that circulates the most in the United States, announced , Friday September 10, the American health authorities.

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 vaccines against severe forms of the virus.

This announcement comes the day after the unveiling of the new muscular strategy of US President Joe Biden to end the pandemic. In particular, a decree requires employees of large American companies to be vaccinated or to undergo a weekly screening test.

“As we have shown, study after study, vaccination works”, insisted the director of the CDC, Rochelle Walenksy, during a press conference. The first study analyzed hundreds of thousands of cases of Covid-19 in thirteen U.S. jurisdictions over the period April 4 to June 19, before the Delta proliferated, and compared them to cases of contamination from June 20 to June 17. July.

Moderna’s vaccine significantly more effective

Between these two periods, the risk of a fully vaccinated person being infected with Covid-19 compared to an unvaccinated person increased slightly: a vaccinated person was 11.1 times less likely to be infected, he now has it. 4.5 times less. Protection against hospitalization and death remained stable, but declined further for people 65 and over.

Health authorities are evaluating the need for a third dose, and seniors are likely to be the first to receive it when the Biden administration launches its recall campaign on September 20.

One of the studies analyzed the effectiveness of different vaccines between June and August in more than four hundred hospitals and health centers, and determined that Moderna’s vaccine was the most effective against hospitalizations (95%), ahead of that. from Pfizer (80%) and that of Johnson & Johnson (60%).

It is not 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 to its higher dosage, 100 micrograms, compared to 30 micrograms for Pfizer’s, or the longer interval between the first and second injection (four weeks, compared to three for Pfizer’s), which could create a stronger immune response.