Seroprevalence of COVID-19 Antibodies and Factors Associated with Seropositivity: A Population-based Study

Currently, COVID-19 is a global public health problem. This study aimed to estimate the seroprevalence of antibodies related to Covid-19 in the general population in southern Iran. This cross-sectional population-based study of the seroepidemiological type investigated the serological prevalence of COVID-19 from October to December 2020 in Jahrom, Fars province, Iran. A total of 612 participants were selected using multistage cluster random sampling regardless of age or gender. The dataset in the study included the participants’ demographic information, the history of exposure to COVID-19 patients, the history of PCR tests, and the history of COVID-19 symptoms in previous months. In addition, this study examined the raw and survey weight adjusted estimates with Stata version 14. Finally, logistic regression was performed to identify risk factors for serum prevalence. The participants’ mean age was 38.88±13.91 and the majority were 30 to 49 years (51.4%), with a female preponderance (58.7%). The estimated adjusted seroprevalence was 32.66 (95%CI: 28.93-36.63), with 207 positive cases for either IgG or IgM. The results of multivariable logistic regression showed that seropositivity in the participants was 4.95 times more likely associated with a history of positive PCR test (OR: 4.95, 95%CI: 2.46-10.90) and 2.14 times in patients with a history of muscle pain in previous months (OR: 2.14, 95%CI: 1.03-4.47). The actual number of patients with COVID-19 is significantly higher than the number of cases confirmed by the disease monitoring system based on PCR tests. Therefore, tracking individuals’ contact with confirmed patients using extensive testing and segregation of asymptomatic patients can help control the epidemic.