2018; Rostami et al. from 60.6% to 82.5% (Kalantari et al. 2018). The current study aimed to evaluate the seroprevalence of infection amongst patients with COVID-19. The possible association between COVID-19 and latent infection in a group of patients with COVID-19 and COVID-19 negative individuals was also assessed. Methods and materials Study design Two-hundred and sixty-nine PCR-positive COVID-19 patients were enrolled in the current study. All patients were hospitalized at the Babol University of Medical Sciences affiliated hospitals, Babol, Iran, from August 2020 to February 2021. The sample size was calculated using the formula as described below (https://library2.lincoln.ac.nz/documents/Sample-size.pdf): and indicated sample size, 1.96, a proportion of the population having the characteristic and the degree of precision, respectively. The minimum sample size for the determination of seroprevalence rates of latent toxoplasmosis was 188 if by a commercially available enzyme-linked immunosorbent assay (ELISA) (EUROIMMUN, Germany) according to the manufacturers instructions. The optical density of IgG antibody titers was provided at 450?nm by an automatic ELISA reader. The results were interpreted based on the kits recommendations. IgG titers of less than 8?IU/mL, between 8 and 11?IU/mL and higher than 11?IU/mL were considered negative, border line and positive, respectively. The sensitivity of the test was 99.9%, and the specificity was 100%. Statistical analysis SPSS v. 22.0 software (SPSS Inc., USA) was used to analyse the results, and infection was evaluated by Chi-squared test (test. Results The mean and standard deviation of the patients age were 60.9??17.6?years, ranging GNF 5837 from 9 to 90?years. One-hundred and five out of 269 individuals (39.0%) were male, and 164 (61.0%) were female. Anti-antibodies were found in 226/269 (84.0%) individuals with COVID-19. The rate of recurrence of IgG antibodies against GNF 5837 relating to demographic and medical data amongst individuals with COVID-19 is definitely demonstrated in Table ?Table1.1. The prevalence of IgG antibodies against experienced a slightly higher rate in individuals aged over 60?years, in comparison with other age groups (antibodies (IgG) and demographic and clinical characteristics amongst the individuals. Table 1 Seroprevalence of illness according to the demographic and medical data of individuals with COVID-19 (269) going to the Babol University or college affiliated Hospital, Babol, Iran (%)valueexposure amongst individuals with COVID-19 and subjects without COVID-19 relating to age, gender and IgG titer (%)(%)valueexposure? Yes72 (79.1)96 (78.0)1.1 (0.55C2.07)0.85? No19 (20.9)27 (22.0)Gender? Female48 (52.7)63 (51.2)1.1 (0.62C1.83)0.83? Male43 (47.3)60 (48.8)Age (years)?? ?3018 (19.8)64 (52.0)0.2 (0.11C0.39)0.00?? ?3073 (80.2)55 (48.0)Median and IQRs of age (years)41 (34C47)30 (29C42)-0.00Median and IQRs of IgG titer97.3 (31.0C133.5)34.4 (13.0C144.5)-0.10 Open in a separate window Discussion A strong negative covariation between toxoplasmosis and COVID-19 was reported by a study (Jankowiak et al. 2020). The present study found that 84% of the individuals with COVID-19 were positive for anti-antibodies (IgG). Earlier reports depicted lower levels of seroprevalence in the north of Iran (Bayani et al. 2013; Kalantari et al. 2018; Rostami et al. 2016). An important associated factor in the epidemiology of toxoplasmosis is definitely age, and several studies demonstrated the seroprevalence rate of toxoplasmosis raises with age and the maximum level was observed in instances more than 50?years (Nasiru Wana et al. 2020; Kalantari et al. 2015). GNF 5837 The mean age of the individuals with COVID-19 (60??17.6?years) was higher than the abovementioned studies. Furthermore, this work showed the seropositivity rate of latent toxoplasmosis was not significantly improved by age. Also, no significant association between gender and the seroprevalence of latent toxoplasmosis was observed. These results are not in agreement with earlier studies reporting a statistically significant association between seropositivity and age, and gender (Achaw et al. 2019). The possible explanation for this variance is definitely variations in type of study population and study GNF 5837 region. In the present study, the prevalence of toxoplasmosis was not significantly higher in severe instances, which may possess confirmed no Pax1 relationship between SARS-CoV-2 and illness. Moreover, a non-matched caseCcontrol study was performed in the second step of the current work which found that the seroprevalence rate for anti-IgG antibodies was not significantly different between case and control organizations (79.1% vs. 78.0%). This getting was not supported by Sharaf-El-Deen and colleagues study which shown the prevalence of toxoplasmosis was significantly higher in patient with COVID-19 than healthy individuals. Their findings also showed the number of positive instances was statistically significant higher in the severe patient group compared with the moderate patient group (Sharaf-El-Deen et al. 2021). The main possible reasons for this controversy are variations in type of study region and endemicity of toxoplasmosis (Abbas et.