Moderna vs Pfizer vaccines: What the first efficacy comparison showed

All mRNA vaccines are very effective and provide significant protection, but those of Moderna appear to be slightly better than those of Pfizer / BioNTech, according to the first direct comparison of their effectiveness made by American scientists. The comparison was based on an analysis of the electronic medical records of nearly 450.000 people who had received the two coronavirus vaccines.

The study, led by Dr. Barbra Dickerman of the Department of Epidemiology at Harvard University School of Public Health and published in the New England Journal of Medicine, shows that the Moderna vaccine provides an approximately 21% lower risk of infection. Covid-19 and 41% lower risk of hospitalization than Pfizer / BioNTech.

"Both vaccines are incredibly effective, with rare cases of breakthrough infections in vaccinated people. "But no matter which strain prevailed - first the Alpha and then the Delta - the Moderna vaccine was slightly more effective," said Juan Kazas, an associate professor of epidemiology at Harvard Medical School and Brigham & Women's Hospital in Boston. .

Efficacy was compared on the basis of five indicators: Cases of disease Covid-19, incidents with symptoms, hospitalizations, ICU admissions and deaths from Covid-19. The comparison was initially made to 219.842 U.S. Army veterans who had been vaccinated with Pfizer between January and May 2021 and as many others who had been vaccinated with Moderna.

In the next 24 weeks after vaccination (at a time when the alpha variant was prevalent), the risk of coronavirus infection was estimated at 4,52 cases per 1.000 people vaccinated with Moderna versus 5,75 per 1.000 with Pfizer. Also, compared to those vaccinated with Moderna, there were more cases of the disease in the group of people vaccinated with Pfizer Covid-19 with symptoms (0,44 per 1.000 people), hospitalizations (0,55 / 1.000), ICU admissions (0,10 / 1.000) and deaths (0,02 / 1.000).

The lowest risk after the Moderna vaccine was confirmed over a longer period of time (July-September 2021), when the Delta variant was now prevalent. In this comparison, the exaggerated risk of a diagnosed infection Covid-19, 12 weeks after vaccination, there were 6,54 cases per 1.000 people for the Pfizer vaccine, compared with the Moderna vaccine.

"Given the high efficacy of both Moderna and Pfizer vaccines, as confirmed by our study, either is recommended as an option," said Dr. Dickerman. The researchers noted, however, that further evaluation of the comparative efficacy and safety of the two mRNA vaccines was needed.

Source: RES-EAP