vaccination coverage for covid-19 in sri lanka: with and without age stratification on susceptible-infectious-recovered simulation

Background: vaccination against covid-19 is as a key solution to interrupt its spread. this study aimed to describe the vaccination coverage required to stop the spread of covid-19 in sri lanka using a mathematical modeling strategy. materials & methods: this longitudinal study used age-stratified and unstratified susceptible-infectious-recovered (sir) models. data on the population's age distribution were acquired from the census report of the census and statistics center of sri lanka, consisting of groups: below 30, between 30-59, and over 60. models with differential equations forecasted the spread of covid-19 with vaccination based on parameter estimates and numerical simulation, assuming fixed population, infection, and recovery rates. results: simulations investigated how the susceptible, infected, and recovered populations varied according to the different vaccination coverages. according to the results, 75% vaccination coverage was required in the entire population of sri lanka to interrupt the transmission of covid-19 completely. the age-stratified sir model showed that over 90% of vaccination coverage in each age group (below 30, between 30-59, and over 60) was required to interrupt the transmission of covid-19 in the country altogether. conclusions: the number of covid-19 infections in each age group of sri lanka reduces with the increase in vaccination coverage. as 75% vaccination coverage is required in sri lanka to interrupt the transmission of the disease, precise vaccination coverage measurement is essential to assess the successfulness of a vaccine campaign and control covid-19.