CDC study: Moderna vaccine most effective at preventing hospitalization

A recent study published by the U.S. Centers for Disease Control and Prevention on Sept. 17 found that the Moderna vaccine was the most effective at preventing hospitalization due to the novel coronavirus after comparing all three coronavirus vaccines authorized in the U.S.

Researchers noted that Moderna’s vaccine was 93% effective while the Pfizer vaccine provided 88% protection and Johnson & Johnson’s vaccine provided 71% protection. 

The CDC’s nationwide study consisted of more than 3,600 adults who were hospitalized for COVID-19 between March and August 2021. 

"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 report read. 

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"Although these real-world data suggest some variation in levels of protection by vaccine, all FDA-approved or authorized COVID-19 vaccines provide substantial protection against COVID-19 hospitalization," the report continued.

Researches noted that what makes Moderna’s vaccine more effective at preventing hospitalization is a decline in efficacy from the Pfizer shot that researchers found to begin roughly four months after people were fully vaccinated with those shots. 

"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 explains. 

"Vaccine effectiveness for the Pfizer-BioNTech vaccine was 91% at 14-120 days after receipt of the second vaccine dose but declined significantly to 77% at more than 120 days," researchers added. 

Recently, an advisory panel for the U.S. Food and Drug Administration on Friday voted to reject a plan to offer a booster dose of Pfizer-BioNTech’s COVID-19 vaccine for Americans saying more data is needed to determine if boosters are safe and effective.

While the CDC’s study shows the Moderna vaccine being more effective at preventing hospitalization, Pfizer’s vaccine, which is now being marketed as Comirnaty, carries the strongest endorsement from the FDA after being granted full approval last month. 

The emergency-use authorization (EUA) last winter allowed Pfizer’s vaccines to be administered before receiving full approval. The difference between EUA and full FDA approval is that they require different clinical studies, with full FDA approval requiring a longer monitoring period.

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Since that time, the two-dose shot regiment — along with vaccines from Moderna and Johnson & Johnson — has drastically improved the United States’ pandemic response. The winter surge that resulted in as many as 300,000 new cases in a single day sharply declined, as did the country’s hospitalization and death rates.

Kelly Hayes and Megan Ziegler contributed to this story.