Studies say that Moderna’s vaccine is more effective against Delta than Pfizer’s vaccine

Photo: Dadu Rovich/Reuters

Moderna’s vaccine was more effective against the delta variant, which originated in India, than the Pfizer and BioNTech vaccines, according to two studies published in medRxiv Sunday (8), prior to peer review. The delta variant is of concern, meaning that it is highly transmissible and rapidly spreading worldwide, becoming prevalent in many countries.

In a study of more than 50,000 patients in the Mayo Clinic Health System, researchers found that the effectiveness of the Moderna vaccine against delta infection was 76% in July — when the delta variant was prevalent — compared to 86% in the baseline for 2021.

Over the same period, the researchers said, the effectiveness of the Pfizer/BioNTech vaccine dropped from 76% to 42%.

While both vaccines remain effective in preventing hospitalization for Covid, a booster shot of Moderna may soon be needed for anyone who received the Pfizer or Moderna vaccines earlier this year, according to the analytics firm’s Dr. Venky Soundararajan. study.

In a separate study, nursing home residents in Ontario, Canada, produced stronger immune responses—particularly on the more worrisome strains of infection—after the Moderna vaccine compared to the Pfizer/BioNTech vaccine.

However, older adults may need higher doses of the vaccine, boosters and other preventive measures, said Anne-Claude Gingras of the Lunenfeld Tannenbaum Research Institute in Toronto, who led the Canadian study. When asked about the two research reports, a Pfizer spokesperson said:

“We continue to believe that a third booster dose may be needed within 6 to 12 months after full vaccination to maintain the highest levels of protection.”