Seroprevalence of SARS-CoV-2 antibody among urban Iranian population: findings from the second large population-based cross-sectional study

Abstract

Background The first large serosurvey in Iran found a SARS-CoV-2 antibody seroprevalence of 17.1% among the general population in the first wave of the epidemic by April, 2020. The purpose of the current study was to assess the seroprevalence of COVID-19 infection among Iranian general population after the third wave of the disease. Methods This population-based cross-sectional study was conducted on 7411 individuals aged ≥10 years old in 16 cities across 15 provinces in Iran between January and March, 2021. We randomly sampled individuals registered in the Iranian electronic health record system based on their national identification numbers and invited them by telephone to a healthcare center for data collection. Presence of SARS-CoV-2-specific IgG and IgM antibodies was assessed using the SARS-CoV-2 ELISA kits. The participants were also asked about their recent COVID-19-related symptoms, including cough, fever, chills, sore throat, headache, dyspnea, diarrhea, anosmia, conjunctivitis, weakness, myalgia, arthralgia, altered level of consciousness, and chest pain. The seroprevalence was estimated after adjustment for population weighting and test performance. Results The overall population-weighted seroprevalence adjusted for test performance was 34.2% (95% CI 31.0-37.3), with an estimated 7,667,874 (95% CI 6,950,412-8,362,915) infected individuals from the 16 cities. The seroprevalence varied between the cities, from the highest estimate in Tabriz (39.2% [95% CI 33.0-45.5]) to the lowest estimate in Kerman (16.0% [95% CI 10.7-21.4]). In the 16 cities studied, 50.9% of the seropositive individuals did not report a history of symptoms suggestive of COVID-19, implying an estimation of 3,902,948 (95% CI 3,537,760-4,256,724) asymptomatic infected individuals. Conclusions Nearly one in three individuals were exposed to SARS-CoV-2 in the studied cities by March 2021. The seroprevalence increased about two-fold between April, 2020, and March, 2021.

Changing Patterns of SARS-CoV-2 Seroprevalence: A Snapshot among the General Population in Kuwait

“…This demonstrates an increase in seropositivity in Kuwait with the progression of the pandemic. Our seroprevalence rates are similar to those reported in neighboring countries such as Saudi Arabia (24.3%) [ 18 ], Oman (22%) [ 19 ], and Iran (23.8%) [ 20 ]. This could be because in late 2020, rapid increases in SARS-CoV-2 infection rates were observed in all age groups with the emergence of the more transmissible Alpha variant.…”

Cumulative incidence of SARS‐CoV‐2 infection in the general population of the Valencian Community (Spain) after the surge of the Omicron BA.1 variant

“…To date, only a handful of seroepidemiological studies extending into the Omicron wave have been performed in the general population. 4 , 5 , 6 Here, we conducted a cross‐sectional serosurvey to estimate the prevalence of SARS‐CoV‐2 antibodies in the general VC population after the Omicron BA.1 variant surge and retrieved prior documented SARS‐CoV‐2 infection data for the recruited population from the RedMiVa VC registry. Our results can probably be extrapolated to other autonomous communities in Spain, as previously suggested.…”

Cumulative incidence of SARS-CoV-2 infection in the general population of the Valencian Community (Spain) after the surge of the Omicron BA.1 variant

“…[12][13][14] Only a handful of seroepidemiological studies have been performed to date in the general population extending into the Omicron wave. [4][5][6] The proportion of infected individuals has dramatically increased following the surge of the Omicron sub-lineages, due to their increased transmissibility and escape from vaccine or infection-induced immunity. 15 Moreover, as the percentage of Omicron-infected paucisymptomatic or asymptomatic individuals appears to be high, the number of underreported infections that are not captured by community surveillance systems may be significantly greater.…”

“…A few serosurvey studies have been reported involving the general population and extending into the Omicron wave; 4-6 these studies provide valuable information on the extent of transmission in the past and contribute towards understanding the future course of the pandemic and to shaping public health decision making. Here, as part of the ProVaVac Valencian COVID-19 vaccine research program launched by the VC government in March 2021, we conducted a population-based study aimed primarily at estimating the cumulative incidence of SARS-CoV-2 infection in the general VC population after the surge and spread of the Omicron BA.1 variant.…”

“…2 Due to the particular nature of SARS-CoV-2 infection with a large proportion of asymptomatic cases, limited testing among individuals with suspected COVID-19, and suboptimal contact tracing, registries of confirmed COVID-19 cases tend to underestimate the cumulative incidence of SARS-CoV-2 infection, as previously shown in the ENE-COVID study, a nationwide, population-based, seroepidemiological study conducted in Spain during 2020. 3 A few serosurvey studies have been reported involving the general population and extending into the Omicron wave; [4][5][6] these studies provide valuable information on the extent of transmission in the past and contribute towards understanding the future course of the pandemic and to shaping public health decision making. Here, as part of the ProVaVac Valencian COVID-19 vaccine research program launched by the VC government in March 2021, we conducted a population-based study aimed primarily at estimating the cumulative incidence of SARS-CoV-2 infection in the general VC population after the surge and spread of the Omicron BA.1 variant.…”