Moderna COVID-19 Vaccine Tied to Lower Adverse Event Risk in Older Adults

FRIDAY, Aug. 11, 2023 (HealthDay News) -- The mRNA-1273 (Moderna) vaccine against COVID-19 is associated with a slightly lower risk for several adverse events in older adults compared with BNT162b2 (Pfizer), according to a study published online Aug. 2 in JAMA Network Open.

Daniel A. Harris, Ph.D., from Brown University in Providence, Rhode Island, and colleagues examined safety differences between mRNA vaccines for COVID-19 by frailty level. Twelve adverse events were included, such as pulmonary embolism, thrombocytopenia purpura, myocarditis, and others. The retrospective analysis included 6.4 million U.S. adults (66 years and older) receiving dose 1 of the mRNA-1273 or BNT162b2 vaccine Dec. 11, 2020, to July 11, 2021.

The researchers found that the risk for 12 adverse outcomes was low in both vaccine groups. Risk was lower with the mRNA-1273 vaccine for pulmonary embolism (risk ratio [RR], 0.96; 95 percent confidence interval [CI], 0.93 to 1.00; risk difference, 9 events per 100,000 persons), with a similar trend seen for other adverse events in subgroup analyses (e.g., 11.0 percent lower risk for thrombocytopenia purpura among nonfrail individuals). There was also a lower risk for being diagnosed with COVID-19 following the mRNA-1273 vaccine (RR, 0.86; 95 percent CI, 0.83 to 0.87), although this benefit was attenuated by frailty level (frail: RR, 0.94; 95 percent CI, 0.89 to 0.99).

"In this cohort study of older U.S. adults, the mRNA-1273 vaccine was associated with a slightly lower risk of several adverse events compared with BNT162b2, possibly due to greater protection against COVID-19," the authors write.

Several authors disclosed ties to pharmaceutical companies, including Moderna and Pfizer.

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