en Epidemiology Original Article <address style="font-style: normal; text-align: justify;"><span style="font-size:11pt"><span style="line-height:250%"><span calibri="" style="font-family:"><b><span style="font-size:9.0pt"><span style="line-height:250%"><span arial="" style="font-family:"><span style="color:black">Background:</span></span></span></span></b><span style="font-size:9.0pt"><span style="line-height:250%"><span arial="" style="font-family:"><span style="color:black"> 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.</span></span></span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:250%"><span calibri="" style="font-family:"><b><span style="font-size:9.0pt"><span style="line-height:250%"><span arial="" style="font-family:"><span style="color:black">Materials & Methods:</span></span></span></span></b><span style="font-size:9.0pt"><span style="line-height:250%"><span arial="" style="font-family:"><span style="color:black"> This <a name="_Hlk101952732">longitudinal</a> study used <a name="_Hlk101195886">age-stratified and unstratified </a><a name="_Hlk101164811">Susceptible-Infectious-Recovered (SIR) </a><a name="_Hlk101165466">models.</a><a name="_Hlk101196092"> </a>Data on the population&#39;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.</span></span></span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:250%"><span calibri="" style="font-family:"><b><span style="font-size:9.0pt"><span style="line-height:250%"><span arial="" style="font-family:"><span style="color:black">Results:</span></span></span></span></b><span style="font-size:9.0pt"><span style="line-height:250%"><span arial="" style="font-family:"><span style="color:black"> 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 <a name="_Hlk101966841">in each age group (below 30, between 30-59, and over 60) </a>was required to interrupt the transmission of COVID-19 in the country altogether. </span></span></span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:250%"><span calibri="" style="font-family:"><b><span style="font-size:9.0pt"><span style="line-height:250%"><span arial="" style="font-family:"><span style="color:black">Conclusions: </span></span></span></span></b><span style="font-size:9.0pt"><span style="line-height:250%"><span arial="" style="font-family:"><span style="color:black">The <a name="_Hlk101963114">number of COVID-19 infections in each age group of Sri Lanka reduces with the increase in vaccination coverage. </a>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.</span></span></span></span></span></span></span><br> &nbsp;</address> COVID-19,COVID-19 Vaccines,Computer Simulation,Epidemiological Models, 91 98 http://johe.rums.ac.ir/browse.php?a_code=A-10-463-1&slc_lang=en&sid=1 A.M.C.H. Attanayake succ@kln.ac.lk 22400319475328460011287 22400319475328460011287 Yes Senior Lecturer in Statistics, Dept. of Statistics & Computer Science, Faculty of Science, University of Kelaniya, Kelaniya, Sri Lanka. University of Kelaniya