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Moderna VS Pfizer: New Study Names The Most Effective COVID-19 Vaccine


Rachael Funnell


Rachael Funnell

Writer & Senior Digital Producer

Rachael is a writer and digital content producer at IFLScience with a Zoology degree from the University of Southampton, UK, and a nose for novelty animal stories.

Writer & Senior Digital Producer

moderna vs pfizer most effective covid vaccine

In the battle of Moderna VS Pfizer, one vaccine comes out on top. Image credit: StanislavSukhin / / IFLScience

In a first of its kind comparative analysis, new research staged a head-to-head between two of COVID-19’s greatest nemeses: Moderna VS Pfizer. Using electronic records from US veterans who received one of these two vaccines, researchers determined who came out on top when it came to preventing COVID-19 and reducing the likelihood of hospitalization or death.

Published in the New England Journal of Medicine, the study delivered good news: both Moderna (mRNA-1273) and Pfizer-BioNTech (BNT162b2) were highly effective in all three categories. However, when it came to picking a winner, it was Moderna who came out on top, offering a lower risk of infection and hospitalization against the dominant strains Alpha and Delta.


“Both vaccines are incredibly effective, with only rare breakthrough cases,” said Dr J.P. Casas, a member of the research team from the U.S. Department of Veterans Affairs, in a statement. “But regardless of the predominant strain – Alpha earlier and then Delta later – Moderna was shown to be slightly more effective.”

When it came to battling SARS-CoV-2, the virus that causes COVID-19, Moderna was found to have a 21 percent lower risk of documented infection. Moderna also carried a 41 percent reduced risk of hospitalization compared to Pfizer-BioNTech.

How to decide the most effective COVID vaccine

The researchers assessed the effectiveness of Moderna VS Pfizer-BioNTech by examining five COVID-related outcomes:

  • Documented COVID-19
  • Symptomatic disease
  • Hospitalization
  • ICU admission
  • Death

These five outcomes were compared in the cases of US veterans who received either the Moderna or Pfizer-BioNTech vaccine from January to May 2021, with over 210,000 participants in each group. During this data collection window, the Alpha variant was the dominant strain circulating, meaning these results may vary during a time when Delta or the new COVID-19 strain Omicron are top.


The most significant difference between the Moderna and Pfizer vaccines was the likelihood of documented infection post-vaccine, which was an extra 1.23 cases per 1,000 people in the Pfizer-BioNTech group compared to Moderna. Pfizer-BioNTech also had a higher rate of symptomatic COVID-19, hospitalization, ICU admission and death though the differences here in Moderna VS Pfizer were more subtle.

Moderna VS Pfizer: Which vaccine should I get?

The good news is that both vaccines are very good at their job, and on a personal scale it’s wise to recommend both equally, the researchers say. The significance of the findings come into play on a population-wide scale, and is food for thought for health officials and policymakers

“Given the high effectiveness of both the Moderna and Pfizer vaccines, confirmed by our study, either one is recommended to any individual offered a choice between the two,” said the study’s first author Dr Barbra A. Dickerman, an epidemiology instructor with the Harvard T.H. Chan School of Public Health.

“However, while the estimated differences in effectiveness were small on an absolute scale, they may be meaningful when considering the large population scale at which these vaccines are deployed. This information may be helpful for larger decision-making bodies.”


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