A study published Friday by the Centers for Disease Control and Prevention (CDC) says that the Moderna COVID-19 vaccine is most effective in preventing coronavirus hospitalizations – but all three vaccines approved or authorized by the Food and Drug Administration (FDA) provide “substantial protection.”


What You Need To Know

  • A new study from the U.S. Centers for Disease Control and Prevention found the Moderna CVID-19 vaccine is the most effective at preventing hospitalizations from the illness

  • The study found Moderna's vaccine is 93% effective at preventing hospitalizations; Pfizer-BioNTech's vaccine is 88% effective, while the single-dose Johnson & Johnson shot is 71% effective

  • The amount of antibodies in individuals who received the Pfizer vaccine decreased after four months, but did not decrease in those who received the Moderna jab

  • While Moderna's vaccine is most effective at preventing hospitalizations in the long term, the CDC noted all three jabs “provide substantial protection against COVID-19 hospitalization"

The study, which observed over 3,600 non-immunocompromised adults across 21 hospitals from March 11–August 15, 2021, found the Moderna vaccine was 93% effective at preventing hospitalizations due to COVID-19. The Pfizer-BioNTech vaccine proved 88% effective at preventing hospitalizations, while Johnson & Johnson’s single-dose regimen came in at 71% effective.

While the “real-world” trial suggests that the two-dose mRNA vaccines provide greater protection than the Johnson & Johnson regimen, the CDC noted all three jabs “provide substantial protection against COVID-19 hospitalization.” 

The discrepancies in protections could be due to a number of factors, including that individuals who received the Johnson & Johnson vaccine had lower antibody levels immediately post-vaccination than those who received either mRNA vaccine. The J&J vaccine is known as a "viral vector vaccine," in which a modified version of a different virus (one that does not cause illness) is injected in order to deliver information to cells. 

The inoculations from Pfizer and Moderna are mRNA vaccines, which teaches cells "how to make a protein ... that triggers an immune response inside our bodies," according to the CDC.

The study also found that the amount of antibodies in individuals who received the Pfizer vaccine decreased after four months, but did not decrease in those who received the Moderna jab. After 120 days, Pfizer vaccine effectiveness dipped to 77%.

Experts say the lasting antibody levels from Moderna could be due to the higher mRNA content in its vaccine or the difference in timing between jabs: The Pfizer-BioNTech shots are spaced out by three weeks, versus a four-week span for the Moderna jabs. 

The CDC noted that the study is subject to a number of limitations, not least of which being that it only studied vaccine effectiveness in non-immunocompromised individuals 18 years old and up. The study also did not take into account the growing prevalence of the highly-contagious delta variant of COVID-19, which has resulted in increased hospitalizations nationwide. 

The study comes as an FDA advisory committee met Friday to discuss Pfizer’s application for a third booster shot for all Americans. The CDC, which will meet next week pending the outcome of Friday’s advisory board meeting, has so far only recommended booster shots for immunocompromised individuals. 

CDC officials hope Friday’s study will help “guide individual choices and policy recommendations regarding vaccine boosters.”