Estimation of Underreporting in the Covid-19 Cases and Hospitalization Registry System Based on Data From a National Survey Publisher



Haghdoost B ; Abdi Z ; Harirchi I ; Ahmadnezhad E
Source: Iranian Journal of Epidemiology Published:2025

Abstract

The COVID-19 pandemic has highly impacted health systems, and the limitations of the national reporting system have reduced the accuracy of estimating the burden of this disease. This study examined the underreporting of COVID-19 cases and hospitalizations using data from the National Survey on Risk Factors for Non-communicable Diseases (STEPS) in Iran in 2021. In this study, 25,425 individuals from the population aged 18 and above were randomly enrolled. In addition to information on non-communicable disease risk factors, participants were questioned about a history of COVID-19 infection, hospitalization, and intensive care unit admission. The frequency of these events was then compared with registry data at the time of data collection. According to the results, 9.3% (95% CI: 8.56 to 9.44) reported a history of COVID-19 infection. Furthermore, among those infected, 12.71% (11.25 to 14.20) reported a history of hospitalization due to COVID-19. Among those hospitalized, 13.74% (8.25 to 18.9) had been hospitalized in intensive care units. Based on this, it is estimated that the sensitivity of recording symptomatic cases was 61.7% (59% to 65%) and for hospitalized cases was 86% (77% to 97.1%). As a conclusion, it can be stated that the registered incidence of symptomatic COVID-19 cases in Iran was underreported by nearly 40%, and hospitalizations due to COVID-19 were underreported by about 15%. Compared to data from many other countries, including developed nations, this situation can be considered as acceptable. © 2025 Elsevier B.V., All rights reserved.