(HealthDay News) — The incidence of selected serious outcomes is not significantly higher at one to 21 versus 22 to 42 days postvaccination with mRNA COVID-19 vaccines, according to a study published online Sept. 3 in the Journal of the American Medical Association.
Nicola P. Klein, M.D., Ph.D., from Kaiser Permanente Northern California in Oakland, and colleagues conducted an interim analysis of safety surveillance data from the Vaccine Safety Datalink to monitor 23 serious outcomes.
The incidence of events that occurred among vaccine recipients one to 21 days after either dose of mRNA vaccine was compared to that of vaccinated comparators who had received their dose 22 to 42 days earlier.
A total of 11,845,128 doses of mRNA vaccines (57 percent BNT162b2) were administered to 6.2 million individuals.
The researchers found that the incidence of events per 1 million person-years during the risk versus comparison intervals was 1,612 versus 1,781 for ischemic stroke; 1,179 versus 1,345 for appendicitis; and 935 versus 1,030 for acute myocardial infarction (rate ratios [95 percent confidence intervals], 0.97 [0.87 to 1.08]; 0.82 [0.73 to 0.93]; and 1.02 [0.89 to 1.18], respectively).
None of the outcome associations met the prespecified requirement for a signal. The incidence of confirmed anaphylaxis was 4.8 and 5.1 per million doses of BNT162b2 and mRNA-1273, respectively.
“It is our top priority to do the science and communicate quickly and clearly with health care providers and the public, as COVID-19 vaccines continue to undergo the most intensive safety monitoring in U.S. history,” a coauthor said in a statement.
Several authors disclosed financial ties to the pharmaceutical industry.