AUTHOR=Jeewandara Chandima , Guruge Dinuka , Abyrathna Inoka Sepali , Danasekara Saubhagya , Gunasekera Banuri , Pushpakumara Pradeep Darshana , Madhusanka Deshan , Jayathilaka Deshni , Ranasinghe Thushali , Somathilake Gayasha , Tanussiya Shyrar , Jayadas Tibutius Tanesh , Kuruppu Heshan , Thashmi Nimasha , Harvie Michael , Wijayamuni Ruwan , Schimanski Lisa , Tan T. K. , Rijal Pramila , Xiao Julie , Ogg Graham S. , Townsend Alain , Malavige Gathsaurie Neelika 

TITLE=Seroprevalence of SARS-CoV-2 Infection in the Colombo Municipality Region, Sri Lanka

JOURNAL=Frontiers in Public Health

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2021.724398

DOI=10.3389/fpubh.2021.724398

ISSN=2296-2565

ABSTRACT=<p><bold>Background:</bold> As the Municipality Council area in Colombo (CMC) experienced the highest number of cases until the end of January 2021, in Sri Lanka, we carried out a serosurvey prior to initiation of the vaccination program to understand the extent of the SARS-CoV-2 outbreak.</p><p><bold>Methods:</bold> SARS-CoV-2 seropositivity was determined in 2,547 individuals between the ages of 10–86 years, by the Wantai total antibody ELISA. We also compared seroprevalence using the haemagglutination test (HAT) to evaluate its usefulness in carrying out serosurveys.</p><p><bold>Results:</bold> The overall seropositivity rate was 24.46%, while seropositivity by HAT was 18.90%. Although The SARS-CoV-2 infection detection rates by PCR were highest in the population between the ages of 20–60 years of age, there was no statistically significant difference in the seropositivity rates in different age groups. For instance, although the seropositivity rate was highest in the 10–20 age group (34.03%), the PCR positivity rate was 9.80%. Differences in the PCR positivity rates and seropositivity rates were also seen in 60–70-year-olds (8.90 vs. 30.4%) and in individuals &gt;70 years (4.10 vs. 1.20%). The seropositivity rate of the females was 29.70% (290/976), which was significantly higher (<italic>p</italic> &lt; 0.002) than in males 21.2% (333/1,571).</p><p><bold>Conclusions:</bold> A high seroprevalence rate (24.5%) was seen in all age groups in the CMC suggesting that a high level of transmission was seen during this time. The higher PCR positivity rates between the ages of 20–60 are likely to be due to increased testing carried out in the working population. Therefore, the PCR positivity rates, appear to underestimate the true extent of the outbreak and the age groups which were infected.</p>