Relative Effectiveness of the Cell-Derived Inactivated Quadrivalent Influenza Vaccine Versus Egg-Derived Inactivated Quadrivalent Influenza Vaccines in Preventing Influenza-Related Medical Encounters During the 2018-2019 Influenza Season in the United States

The cell-propagated inactivated quadrivalent influenza vaccine (ccIIV4) may offer improved protection in seasons where egg-derived influenza viruses undergo mutations that affect antigenicity. This study estimated the relative vaccine effectiveness (rVE) of ccIIV4 versus egg-derived inactivated quadrivalent influenza vaccine (eIIV4) in preventing influenza-related medical encounters in the 2018-2019 U.S. season.