This is analytical research. The goal of this study was to examine the relationship between the number of COVID-19 cases and COVID-19 vaccination among people in Thailand's health zone 4. (Saraburi, Phra-Nakhon Si Ayutthaya, Pathum-Thani, Ang-Thong, Sing-Buri, Nonthaburi, Nakhon-Nayok, and Lop-Buri provinces). The research collected data on secondary research-related data from the Ministry of Public Health and the World Health Organization's reliable website. The information includes the number of COVID-19 cases involved in the research as well as data on COVID-19 vaccination coverage. March– November 2021 is the study period. The data in this study was examined using the frequency, percentage, mean, and standard deviation. Using correlation tests with both a GIS tool to investigate the association between variables. The results of the research indicated that coverage for the first dose of the COVID-19 vaccine was significantly associated with the number of COVID-19 cases (before vaccination), at a level of 0.05, and in the same direction (r = 0.763). Furthermore, at a level of 0.05, coverage for the third dose of the COVID-19 vaccine was significantly associated with the number of COVID-19 cases (before vaccination), and in the same direction as the connection (r = 0.712). While there is no association between coverage for the second dose of the COVID-19 vaccine and the number of COVID-19 cases (before vaccination). However, obtaining COVID-19 vaccine coverage is critical to effectively reducing COVID-19 spread. As a result, policies and campaigns should be included in a diverse variety of relevant methods. The public, as well as governmental and private health organizations, must be continuously involved. Several sorts of media are necessary in the age of global communication. This, however, must be consistent with policy and result in an efficient and equitable operation.

Keywords : The number of COVID-19 cases, Vaccination, Geographic Information Systems (GIS), Thailand