A high-dose recombinant influenza vaccine is more effective than the standard-dose vaccine among adults aged 50-64, according to a study published in the New England Journal of Medicine. Amber Hsiao, PhD, MPH, and colleagues compared the effectiveness of recombinant vaccines versus standard-dose vaccines against influenza-related outcomes in adults younger than 65. During the 2018-2019 and 2019-2020 influenza seasons, facilities administered a high-dose recombinant vaccine or one of two standard-dose vaccines to adults aged 50-64 years and 18-49. Data were included for 632,962 people in the recombinant vaccine group and 997,366 in the standard dose group. The researchers identified 1,386 and 2,435 cases of PCR-confirmed influenza diagnoses in the recombinant vaccine and standard dose groups, respectively. Among participants aged 50-64, 2.00 and 2.34 cases per 1,000 tested positive for influenza in the recombinant vaccine and standard dose groups, respectively, for a relative vaccine effectiveness of 15.3%. Compared with the standard dose vaccines, the recombinant vaccine was not significantly more protective against influenza-related hospitalization.