Challenges to Sustaining Measles Elimination: Transmission Dynamics, Immunity Gaps, and Resurgence in Post-Elimination Settings

Abstract

Measles is a highly contagious viral disease that continues to pose a major public health challenge despite the availability of an effective vaccine. Vaccination programs worldwide have greatly reduced measles cases and deaths, and several countries have achieved elimination. This structured narrative review synthesizes evidence from peer-reviewed literature and public health surveillance reports to examine the drivers of measles resurgence in post-elimination settings, with particular emphasis on the United States. The recent resurgence of measles has been linked to multiple interacting factors, including lower and inconsistent vaccination coverage, vaccine hesitancy, misinformation, structural barriers to healthcare access, differences in immunization policies, and other social determinants that influence vaccine uptake, resulting in outbreaks concentrated in under-vaccinated communities. Importations from areas with ongoing transmission also play an important role. Because of the virus's high transmissibility, even small gaps in immunity threaten sustained elimination. Maintaining elimination requires high vaccination coverage, strong surveillance systems, rapid outbreak response, and community-specific strategies that strengthen vaccine confidence and address localized immunity gaps.