Seasonal influenza vaccination in the Americas: Progress and challenges during the COVID-19 pandemic

BACKGROUND: Vaccination is one of the most effective measures to prevent influenza illness and its complications; influenza vaccination remained important during the COVID-19 pandemic to prevent additional burden on health systems strained by COVID-19 demand. OBJECTIVES: We describe policies, coverage, and progress of seasonal influenza vaccination programs in the Americas during 2019–2021 and discuss challenges in monitoring and maintaining influenza vaccination coverage among target groups during the COVID-19 pandemic. METHODS: We used data on influenza vaccination policies and vaccination coverage reported by countries/territories via the electronic Joint Reporting Form on Immunization (eJRF) for 2019–2021. We also summarized country vaccination strategies shared with PAHO. RESULTS: As of 2021, 39 (89 %) out of 44 reporting countries/territories in the Americas had policies for seasonal influenza vaccination. Countries/territories adapted health services and immunization delivery strategies using innovative approaches, such as new vaccination sites and expanded schedules, to ensure continuation of influenza vaccination during the COVID-19 pandemic. However, among countries/territories that reported data to eJRF in both 2019 and 2021, median coverage decreased; the percentage point decrease was 21 % (IQR = 0–38 %; n = 13) for healthcare workers, 10 % (IQR = -1.5–38 %; n = 12) for older adults, 21 % (IQR = 5–31 %; n = 13) for pregnant women, 13 % (IQR = 4.8–20.8 %; n = 8) for persons with chronic diseases, and 9 % (IQR = 3–27 %; n = 15) for children. CONCLUSIONS: Countries/territories in the Americas successfully adapted influenza vaccination delivery to continue vaccination services during the COVID-19 pandemic; however, reported influenza vaccination coverage decreased from 2019 to 2021. Reversing declines in vaccination will necessitate strategic approaches that prioritize sustainable vaccination programs across the life course. Efforts should be made to improve the completeness and quality of administrative coverage data. Lessons learned from COVID-19 vaccination, such as the rapid development of electronic vaccination registries and digital certificates, might facilitate advances in coverage estimation.