Most Common Adverse Events With JYNNEOS Are Nonserious

THURSDAY, Dec. 8, 2022 (HealthDay News) -- The JYNNEOS vaccine, which is recommended for persons exposed to or at high risk for exposure to mpox virus, seems safe, with the most common adverse health events reported as nonserious, according to research published in the Dec. 9 issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.

Jonathan Duffy, M.D., from the CDC Mpox Emergency Response Team, and colleagues monitored JYNNEOS vaccine safety using the Vaccine Adverse Event Reporting System (VAERS) and the Vaccine Safety Datalink for vaccine recipients of all ages.

During May 22 to Oct. 21, 2022, 987,294 doses of JYNNEOS vaccine were administered in the United States. The researchers found that the most common adverse events reported to VAERS were nonserious and included injection site reactions; this was consistent with prelicensure studies. The rates of adverse health events were similar for doses received by intradermal and subcutaneous administration. In adults, serious adverse events were rare, and none were identified among persons aged younger than 18 years.

"JYNNEOS postlicensure and postauthorization vaccine safety surveillance findings to date are consistent with those observed in the clinical trials, and support JYNNEOS vaccine safety with no new or unexpected safety concerns identified," the authors write. "CDC and FDA will continue to monitor the safety of JYNNEOS. Health care providers should continue to report adverse events after JYNNEOS to VAERS."

One author disclosed financial ties to Janssen Vaccines & Prevention; a second author disclosed ties to health care companies.

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