Epidemiological investigation of the COVID-19 outbreak in Vellore district in South India using Geographic Information Surveillance (GIS)

Objectives Geographical Information Surveillance (GIS) is an advanced digital technology tool that maps location-based data and helps in epidemiological modeling. We applied GIS to analyze patterns of spread and hotspots of COVID-19 cases in Vellore district in South India. Methods Laboratory-confirmed COVID-19 cases from the Vellore district and neighboring taluks from March 2020 to June 2021 were geo-coded and spatial maps were generated. Time trends exploring urban-rural burden with an age-sex distribution of cases and other variables were correlated with outcomes. Results A total of 45,401 cases of COVID-19 were detected with 20730 cases during the first wave and 24671 cases during the second wave. The overall incidence rates of COVID-19 were 462.8 and 588.6 per 100,000 populations during the first and second waves respectively. The pattern of spread revealed epicenters in densely populated urban areas with radial spread sparing rural areas in the first wave. The case fatality rate was 1.89% and 1.6% during the first and second waves that increased with advancing age. Conclusions Modern surveillance systems like GIS can accurately predict the trends and pattern of spread during future pandemics. A real-time mapping can help design risk mitigation strategies thereby preventing the spread to rural areas.