RIV3 flu vaccine safe for routine use in all adults
A phase 4 post-marketing study of RIV3, a recombinant trivalent influenza vaccine, demonstrated no safety concerns regarding its use in adults.

“This safety study was done as a commitment made by the manufacturer of the trivalent recombinant influenza vaccine (RIV3) to the FDA after it was approved in 2014,” John Hansen, MPH, adverse event coordinator and project manager at Kaiser Permanente Vaccine Study Center, told Healio.

Hansen and colleagues conducted the observational safety study in persons aged 18 years and older who were vaccinated with RIV3 or the trivalent, standard-dose inactivated influenza vaccine (IIV3) at Kaiser Permanente Northern California during the 2015-2016 influenza season. Researchers compared the rates of prespecified diagnoses of interest during various postvaccination risk intervals, as well as all-cause hospitalization and mortality up to180 days after vaccination. Prespecified diagnoses of interested included Guillain-Barré Syndrome, pericarditis, pleural effusion, narcolepsy/cataplexy, asthma, acute hypersensitivity reactions and fever.
The researchers observed statistically significant differences in the prespecified diagnoses of interest when comparing the 21,976 persons who received RIV3 with the 283,683 who received IIV3. Specifically, RIV3 vaccination was associated with fewer fever diagnoses in the first 41 days after vaccination (OR = 0.38; 95% CI, 0.14-0.86). RIV3 also correlated with fewer all-cause hospitalizations in the 180 days after vaccination (OR = 0.66; 95% CI, 0.61-0.73), which were mostly due to pregnancy-related hospitalizations in IIV3 recipients. There were no serious adverse events or deaths related to RIV3 during the study.
“This analysis provides reassurance that routine use of RIV3 is safe,” Hansen said.