Predictors of anti-SARS-CoV-2 seropositivity: An Egyptian population-based study

Population-based studies on the determinants of COVID-19 seroprevalence constitute a cornerstone in guiding appropriate preventive measures. Such studies are scarce in Egypt, thus we conducted this study to explore risk factors for SARS-CoV-2 seropositivity.

This survey included 2919 participants from 10 Egyptian governorates. Sera were tested for SARS-CoV-2 spike (S) and nucleocapsid (N) antibodies. Univariate and multivariate analyses were performed to identify associated factors and predictors of seropositivity regarding sociodemographic factors, clinical data, and personal practices of participants. A subgroup analysis was performed to investigate the occupational risks of seropositivity.

Seropositivity was recorded in 1564 participants (53.6%). Independent predictors of seropositivity included non-smokers (aOR = 1.817; 95% CI: 1.407-2.346, p = 0.000), having blood group A (aOR = 1.231; 95% CI: 1.016-1.493, p = 0.034), a history of COVID-19 infection (aOR = 2.997; 95% CI: 2.176-4.127, p = 0.000), COVID-19 vaccination (aOR = 4.349; 95%CI: 2.798-6.759, p = 0.000), higher crowding index (aOR = 1.229; 95% CI: 1.041-1.451, p = 0.015), anosmia and/or ageusia (aOR = 3.453; 95% CI: 2.661-4.481, p = 0.000) and history of fever (aOR = 1.269; 95% CI: 1.033-1.560, p = 0.023). Healthcare worker and Obesity/overweight were additional significant predictors of seropositivity among the working participants (aOR = 1.760; 95% CI: 1.301-2.381, p = 0.000 and aOR = 1.384; 95% CI: 1.059-1.808, p = 0.019, respectively). Additional factors showing association with seropositivity in the univariate analysis were: female gender, age group (15-39 years), higher educational level (preparatory and above), lack of environmental disinfection and having roommates at the workplace. There was a positive correlation between the titers of both antibodies. Age was weakly correlated with anti-S titer, while anti-N was significantly correlated with the number of protective measures applied by the participants. Both antibodies were significantly correlated with adult BMI, while both were significantly negatively correlated with the smoking index.

SARS-CoV-2 seropositivity was associated with some personal and behavioral and occupation-related factors. Fever and anosmia and/or ageusia were the symptoms mostly associated with seropositivity.