A 2SIR-VD Model for Optimizing Geographical COVID-19 Vaccine Distribution in the Philippines

Almajose, A. P.; White, A.; Diego, C.; Lazaro, R.; Austriaco, N.

COVID-19 is a novel respiratory disease first identified in Wuhan, China, that is caused by the novel coronavirus, SARS-CoV-2. It has triggered a global pandemic of historic proportions. The government of the Philippines began its national vaccine drive on March 1, 2021, with the goal of vaccinating seventy million of its citizens by the end of the calendar year. To determine the optimum geographical distribution strategy in the Philippines for the limited supply of vaccines that is currently available, we developed and adapted a basic SIR model that allows us to understand the evolution of a pandemic when public health authorities are vaccinating two susceptible populations within a country with different vaccine rates. Our analysis with our 2SIR-VD model revealed that prioritizing vaccine deployment to the National Capital Region (NCR) of the Philippines minimized the number of COVID-19 cases in the country. We therefore recommend deploying 90% of the available vaccine supply to the NCR to mitigate viral transmission there. The remaining 10% would allow the rest of the archipelago to vaccinate all of their senior citizens, thus shielding this vulnerable population against severe disease and death from COVID-19.