Objective:The assessment of novel coronavirus disease 2019 (COVID-19) antibodies is essential to understand the transmission dynamics of contagious disease. The proportion of the population who developed antibodies against the COVID-19 disease can be estimated through population-based serosurveys. This population based cross sectional serosurvey was designed to assess the seroprevalence of IgG and IgM antibodies of COVID-19 infection. Material and methods:A population based cross sectional serosurvey included 1031 residents of Itanagar Capital Complex region (ICR), Arunachal Pradesh, India, aged above five years. Anti-SARS-CoV-2 specific IgG and IgM antibody levels were analyzed by chemiluminescence immunoassay based serological tests. Results:The overall seropositivity for SARS-CoV-2 IgG and IgM was 92.24% and 7.7%, respectively. The seropositivity of IgG and IgM was 97.68% and 2.32%, respectively, in subjects fully vaccinated with two doses, 97.22% and 13.88%, respectively, in those vaccinated with the first dose, and 80% and 11.33%, respectively, in non-vaccinated participants. In contrast to indigenous tribal participants (IgG 90.55% and IgM 8.88%), seroprevalence was high in non-tribal subjects (IgG 94.72% and IgM 6.84%). Age, ethnicity, and area showed a positive correlation, while vaccination status exhibited a negative correlation with IgG levels (Pearson's coefficient -0.535). Conclusions:This first monocentric serosurvey following the high rate of infection with Delta variant in ICR found a high seropositivity for IgG. Further state level serosurveys are needed to assess the infection status, immunological response and associated comorbidities of COVID-19 infection. Periodic vaccination campaigns and early administration of booster doses to the general public might be beneficial in preserving immunity and prevent illness.