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.