Spatial autocorrelation pattern of COVID-19 vaccine coverage in Thailand 2021 and 2022

During the COVID-19 pandemic in 2021-2022, vaccination against this infection was crucial for Thailand's recovery. This research aimed to identify spatial patterns of association between the distribution and spread of the COVID-19 pandemic on the one hand and vaccine coverage, health service and socio-economic factors on the other. Univariate analysis using Getis-Ord GI* found strong clustering of the vaccine coverage, mostly in Eastern, Central, and Southern regions (Andaman coast), while bivariate analysis using Moran's I revealed significant positive spatial correlation vaccine coverage with the presence of COVID-19 patients (2021 = 0.273; 2022 = 0.273), Night Time Light (NTL) (2021 = 0.159; 2022 = 0.118) and medical personnel (2021 = 0.174; 2022 = 0.123). In addition, Local Indicators of Spatial Association (LISA) analysis found High-High clusters predominantly in the Eastern and Central regions. Areas with high economic growth (as reflected by high NTL) had greater COVID-19 vaccine coverage, likely due to better access to information and efficient transport systems in areas with stronger financial resources than elsewhere. These factors facilitated access to healthcare ensured presence of adequate personnel and enabled rapid distribution of the vaccine. Additionally, high rates of COVID-19 infections increased public awareness of infection risk leading to better vaccination uptake. Policymakers should prioritise vaccine distribution in high-risk and underserved areas to ensure equitable access. Additionally, increasing health workforce capacity is essential to improving service efficiency and readiness for future outbreaks.