Prevalence of COVID-19 in Iran: Results of the first survey of the Iranian COVID-19 Serological Surveillance program

Khalagi, K.; Gharibzadeh, S.; Khalili, D.; Mansournia, M. A.; Mirab Samiee, S.; Aghamohamadi, S.; Mir-Mohammad-Ali Roodaki, M.; Hashemi, S. M.; Tayeri, K.; Namdari Tabar, H.; Azadmanesh, K.; Tabrizi, J. S.; Mohammad, K.; Hajipour, F.; Namaki, S.; Raeisi, A.; Ostovar, A.

Abstract Background: This study aims to estimate the prevalence of COVID-19 in the general population of Iran. Methods: The target population was all Iranian people aged six years and older in the country. A stratified random sampling design was used to select 28,314 subjects from among the individuals registered in the electronic health record systems used in primary health care in Iran. Venous blood was taken from each participant and tested for the IgG antibody against COVID-19. The prevalence of COVID-19 was estimated at provincial and national levels after adjusting for the measurement error of the laboratory test, non-response bias, and sampling design. Results: Of the 28,314 Iranians selected, 11,256 (39.75%) participated in the study. Of these, 5406 (48.0%) were male, and 6851 (60.9%) lived in urban areas. The mean (standard deviation) participant age was 35.89 (18.61) years. The adjusted prevalence of COVID-19 until August 20, 2020 was estimated as 14.2% (95% uncertainty interval: 13.3%, 15.2%), which was equal to 11,958,346 (95% confidence interval: 11,211,011-12,746,776) individuals. The prevalence of infection was 14.6%, 13.8%, 16.6%, 11.7%, and 19.4% among men, women, urban population, rural population, and individuals 60 years of age and older, respectively. Ardabil, Golestan, and Khuzestan provinces had the highest prevalence, and Alborz, Hormozgan, and Kerman provinces had the lowest. Conclusions: Based on the study results, a large proportion of the Iranian population had not yet been infected by COVID-19. The observance of hygienic principles and social restrictions should therefore continue until the majority of the population has been vaccinated. Keywords: COVID-19, Seroprevalence, Survey, Nationwide, Population-based, Iran, IgG test