Cross-national patterns of COVID-19 vaccination coverage by vaccine type.

We examined whether COVID-19 vaccine type was associated with national full-vaccination coverage using 1034 country-vaccine entries from 195 countries derived from World Health Organization data. In a country-level analysis adjusting for World Bank income group, WHO region, and the number of vaccine products per country, neither mRNA vaccine availability (p = 0.051) nor the proportion of mRNA vaccines in a country's portfolio (p = 0.164) was significantly associated with coverage. Vaccine-related variables added only one percentage point to the explained variance beyond structural factors (ΔR2=0.011). Unadjusted exploratory analyses showed that some vaccine products were more frequently recorded in high-coverage country contexts, but these patterns were substantially attenuated after adjustment for structural covariates. The apparent link between vaccine category and coverage largely reflected differences in economic capacity, geographic region, and deployment context rather than vaccine category itself.