A study released in July revealed that one in 35 medical staff members at a Swiss medical facility exhibited cardiac damage linked to Moderna's mRNA-1273 vaccination. The study looked specifically at a booster dose of the vaccine. "mRNA-1273 booster vaccination-associated elevation of markers of myocardial injury occurred in about one in 35 persons (2.8%), a greater incidence than estimated in meta-analyses of hospitalized cases with myocarditis (estimated incidence 0.0035%) after the second vaccination," the researchers wrote. The percentage should be under 1% in a healthy group of people. The study group was monitored for 30 days after immunization, hence there are no long-term findings in the study. In the 30 days following the booster, none of the trial participants experienced significant negative side effects. However, the researchers highlighted that individuals were also counseled against engaging in vigorous exercise, which might have lessened any significant issues.