CDC Study Says Moderna Vaccine More Effective Than Pfizer and J&J

September 20, 2021

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A nationwide study of more than 3,600 adults found the Moderna vaccine does a better job at preventing COVID-19 hospitalizations than the two other vaccines being used in the United States, the Centers for Disease Control and Protection said Friday.

"Among U.S. adults without immunocompromising conditions, vaccine effectiveness against COVID-19 hospitalization during March 11–August 15, 2021, was higher for the Moderna vaccine (93%) than the Pfizer-BioNTech vaccine (88%) and the Janssen vaccine (71%)," the agency’s Morbidity and Mortality Weekly Report said. Jansen refers to the Johnson & Johnson vaccine.

The CDC said the data could help people make informed decisions.

"Understanding differences in VE (vaccine effectiveness) by vaccine product can guide individual choices and policy recommendations regarding vaccine boosters. All FDA-approved or authorized COVID-19 vaccines provide substantial protection against COVID-19 hospitalization," the report said.

The study also broke down effectiveness for longer periods. Moderna came out on top again.

After 120 days, the Modern vaccine provided 92% effectiveness against hospitalization, whereas the Pfizer vaccine’s effectiveness dropped to 77%, the CDC said. There was no similar calculation for the Johnson & Johnson vaccine.

The CDC studied 3,689 adults at 21 hospitals in 18 states who got the two-shot Pfizer or Moderna vaccine or the one-shot Johnson & Johnson vaccine between March and August.

The agency noted some factors that could have come into play.

"Differences in vaccine effectiveness between the Moderna and Pfizer-BioNTech vaccine might be due to higher mRNA content in the Moderna vaccine, differences in timing between doses (3 weeks for Pfizer-BioNTech versus 4 weeks for Moderna), or possible differences between groups that received each vaccine that were not accounted for in the analysis," the report said.

The CDC noted limitations in the findings. Children, immunocompromised adults, and vaccine effectiveness against COVID-19 that did not result in hospitalization were not studied.

Other studies have shown all three U.S. vaccines provide a high rate of protection against coronavirus.


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