Global resurgence of measles in the vaccination era and influencing factors

OBJECTIVES: Recent years have seen increased cases of measles despite widespread vaccination. We examined the potential drivers behind the resurgence of measles. METHODS: We analyzed the trends in measles incidence and vaccine coverage from 2010 to 2019 across World Health Organization member countries using country-level linear regression models. We computed the Spearman rank correlation coefficient (ρ) between measles incidence and socioeconomic and vaccination-related variables using published data from the World Health Organization member countries to identify the key factors influencing measles incidence. RESULTS: Between 2010 and 2019, global measles cases fluctuated, with a notable rise in 2019 (measles cases per million in 2019 was about 140% higher than in 2010), alongside a declining vaccination coverage in many countries (59 of 194 countries). Among 10 socioeconomic factors examined, per-capita national gross income, population literacy, urban residences, and political stability were significantly associated with measles incidence (ρ <0, and P <0.05 for all these variables). These factors likely reflect the quality of public health infrastructure (e.g. access to vaccines), particularly, in low- and middle-income countries. In addition, a stratified analysis suggests vaccine hesitancy likely contributed to measles case increases in high- and upper middle-income countries. CONCLUSIONS: The socioeconomic determinants of measles transmission are interconnected and region-specific. The availability of public health resources and political stability significantly influence measles burdens in low- and middle-income countries, whereas vaccine hesitancy presents a unique challenge to measles elimination in high- and upper middle-income countries.