Helminth Seropositivity Inversely Correlated with Th1 and Th17 Cytokines and Severe COVID-19

The COVID-19 pandemic has significantly impacted global health. However, Africa has reported relatively low numbers of cases and fatalities. Although the pandemic has largely receded, the reasons for its milder course on the African continent have not yet been fully clarified. This study explored the hypothesis that helminth co-infections may have contributed to these observations. A retrospective cohort study was conducted using 104 archived plasma samples collected during the third wave of the pandemic in the Ashanti Region of Ghana. ELISA and Luminex assays were used to measure SARS-CoV-2-specific IgA and IgG, neutralizing antibodies, and helminth-specific IgG levels. The results indicated that the highest cumulative seroprevalence of helminths (61.5%) was observed in asymptomatic SARS-CoV-2-infected individuals. In comparison, mild and moderate COVID-19 patients had helminth seropositivity rates of 43.8% and 34.5%, respectively, which were 1.4 and 1.8 times lower than those of the asymptomatic group, respectively. Notably, the two severe COVID-19 cases investigated were seronegative for all three helminths tested. Strikingly, co-exposure resulted in lower SARS-CoV-2-specific IgA/IgG expression and reduced neutralization potential. However, in the plasma of individuals co-seropositive for helminths and SARS-CoV-2, a significantly higher expression of Th2 cytokines and IL-10 over Th1 was observed compared to those who were SARS-CoV-2 positive alone. These data suggest that co-exposure to helminths could mitigate severe COVID-19 outcomes by reducing the Th1 and Th17 responses. Our study highlights the potential protective role of helminth co-infection against severe COVID-19, suggesting that helminth-induced immune modulation may improve clinical outcomes. These findings provide valuable insights for public health policies in helminth-endemic regions and underscore the importance of considering helminth co-infections in managing viral infections.