Relationship of post COVID syndrome with blood type, sex and diseases in young people

The COVID-19 pandemic has affected over 700 million individuals worldwide, with a substantial number of confirmed cases still ongoing. A significant proportion of patients (10% to 77.7%) continue to experience symptoms associated with post-COVID syndrome (PCS). However, research concerning the incidence and progression of PCS has predominantly focused on older patients with comorbidities, leaving a knowledge gap regarding its effects in young, relatively healthy adults. Objective. To evaluate the relationship between the incidence of post-COVID syndrome and blood type, gender, and comorbidities in relatively healthy adults. Materials and methods. A total of 115 participants were surveyed to detect signs of PCS; the respondents were young (20–45 years old), healthy or with comorbidities, and had no ongoing therapy. Data collected included gender, age, blood group (according to the ABO system and Rh factor), the presence of comorbid conditions, smoking status, and COVID-19 vaccination history. Results. Among the participants, COVID-19 was confirmed in 95.6% (n=110). Of these, 67% exhibited symptoms consistent with PCS, with incidence higher among women (85%) than among those without PCS (64%; p=0.03). Notably, among participants with PCS, those with blood group A (II) were more prevalent, constituting 47.3% in the PCS group vs. 22.2% in the non-PCS group (OR, 2.42; 95% CI, 1.39-4.2). In contrast, blood groups B (III) and AB (IV) were less common among those with PCS, with prevalence rates of 16.2% and 5.4%, respectively, compared to 44.4% and 16.7% in the non-PCS group (p=0.0008). Additionally, individuals with digestive system conditions were more frequently observed in the PCS group (20.3% vs. 5.6%; OR 7.14, 95% CI 1.23-50.0; p=0.03). Conclusions. The findings indicate that post-COVID syndrome occurs more frequently in women, individuals with blood type A (II), and those with concurrent digestive system diseases. It is plausible that these groups have higher susceptibility to SARS-CoV-2 persistence, or that men and individuals with blood group B (III) or AB (IV) have protective mechanisms that mitigate the effects of infection.