ABSTRACT
Background: Celiac disease (CeD) is an autoimmune disorder characterized by an inflammatory immune response against gluten and increased susceptibility to bacterial and viral infections. After the coronavirus disease 2019 (COVID-19) pandemic began, several studies showed no difference in infections rates of SARS-CoV-2 between patients with CeD and the general population. However, all studies were based on diagnosed CeD patients who are likely on a gluten-free diet;the immune system of these patients is similar to the general population, which is not likely to show an increased risk of COVID-19. On the contrary, individuals with undiagnosed CeD are likely to be susceptible to viral infections due to abnormally overactivity of the immune system. We aimed to evaluate the frequency of SARSCoV- 2 positivity and related to hospitalization in hidden CeD patients and diagnosed CeD and compare the vaccination rate in these groups. Methods: Based on the previous community cohort of subjects who were tested for CeD serology, we categorized them into three groups: hidden CeD, diagnosed CeD, and seronegative controls. Data of COVID-19 were obtained from January 2020 through September 2021, utilizing polymerase chain reaction (PCR) test results for SARS-CoV-2 and corresponding hospitalization records. Results: A total of 207 hidden celiac disease, 68 diagnosed CeD, and 22,213 seronegative controls were included in the study. Table 1 summarizes the COVID-19 PCR tests, positivity rate, hospitalization, and vaccination rate. Remarkably, about two thirds of the community in the study population were tested for SARS-CoV-2. SARS-CoV-2 PCR tests were more frequently conducted in the diagnosed CeD group (78%), compared to the undiagnosed CeD (68%) or seronegative group (63%) (p=0.01). The positivity rate among subjects tested for SARSCoV- 2 was higher in the seronegative group (15.3%) than that of undiagnosed CeD (14.3%) or diagnosed CeD (7.5%), but it was not statistically significant. Of 2,125 subjects with positive SARS-CoV-2 results in the seronegative group, about 8.1% (n=172) were hospitalized, while only one patient with undiagnosed CeD (out of 20 positive cases) was hospitalized. Interestingly, vaccination rates among the three groups were similar (48% in the seronegative group, 49% in the undiagnosed CeD, and 53% in the diagnosed CeD). Conclusions: This study demonstrated no difference in susceptibility to SARS-CoV-2 infection in undiagnosed or diagnosed CeD. Testing rate is higher in diagnosed CeD, which is likely to be related to health-seeking behavior. (Table Presented)