(NEXSTAR) – A direct study of Moderna and Pfizer vaccines determined the former to be slightly more effective against COVID-19, at least when it comes to alpha and delta variants.
The results of the study, conducted by researchers at Harvard Medical School, Harvard TH Chan School of Public Health, Brigham and Women’s Hospital and the Veterans Administration, were published this week in the New England Journal of Medicine. .
The results indicated that subjects who received the Moderna vaccine (mRNA-1273) were less likely to experience COVID-19 results than those who received the Pfizer-BioNTech vaccine (BNT162b2) during periods of alpha or delta dominance. Specifically, when the alpha variant was predominant, the researchers recorded 4.52 infections per 1,000 study participants who received the Moderna vaccine, but 5.75 infections per 1,000 among those who received the Pfizer vaccine. During delta dominance, an additional 6.54 infections per 1,000 were recorded in the Pfizer group.
Moderna has also been shown to be slightly more effective against each category of COVID-19 outcome, including infection, symptomatic infection, hospitalization, intensive care treatment, or death.
Both vaccines, however, are very effective against the results of COVID-19, the study authors said.
“Given the high efficacy of the two vaccines, one or the other is strongly recommended for anyone with a choice between the two,” said lead author Barbra Dickerman, epidemiology instructor and researcher at CAUSALab at the Harvard TH Chan School.
Dickerman acknowledged that although the differences in efficiency were slight, “they may be significant for larger decision-making bodies, such as health systems and higher-level organizations, given the large population scale at which these vaccines are being deployed “.
The study, meanwhile, was conducted before the appearance of the omicron variant, which means that more research is needed to assess the effectiveness of either vaccine against the latest mutations.