Share on Pinterest Vaccine vials hanging at the Cruise Center Steinwerder vaccination center in Hamburg. Daniel Bockwoldt/picture alliance via Getty The Moderna and Pfizer vaccines have been highly effective at preventing COVID-19.
In a new study, researchers looked at the differences in effectiveness between the two vaccines.
They found that people who had received two doses of the Moderna vaccine were less likely to develop COVID-19 or become hospitalized with the illness than people who had received the Pfizer vaccine. Both the Moderna and Pfizer COVID-19 vaccines are messenger ribonucleic acid (mRNA) vaccines — a relatively new type of vaccine technology. These COVID-19 vaccines work by providing our cells with instructions for making a SARS-CoV-2 protein. Our immune system then reacts to these proteins and develops the tools to respond to any infection with the virus in the future. Scientists from the Centers for Disease Control and Prevention (CDC) have found that both the Moderna and Pfizer vaccines are very effective at protecting people from COVID-19. CDC Director Dr. Rochelle P. Walensky points to “accumulating evidence that mRNA COVID-19 vaccines are effective and should prevent most infections.” She adds that “Fully vaccinated people who still get COVID-19 are likely to have milder, shorter illness and appear to be less likely to spread the virus to others.” “These benefits are another important reason to get vaccinated.”
89 million people In the latest study, researchers investigated the differences in rates of “breakthrough” cases of COVID-19 among people who received the Moderna or Pfizer vaccines. A breakthrough case is when the disease develops in someone who has been fully vaccinated against it. The team was also interested in any differences between rates of hospitalization and death due to COVID-19 among people who received either vaccine. For their analysis, the researchers drew on health records from 89 million people in the United States. The data included people with a wide range of demographic characteristics. The team looked at data taken between July and November 2021, when the Delta variant of COVID-19 was the main variant of the virus. The results appear as a research letter in JAMA .