Immunomodulation of COVID-19 severity by helminth co-infection: Implications for COVID-19 vaccine efficacy

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an emerging virus in late 2019 causing coronavirus disease 2019 (COVID-19), has caused a catastrophic effect, resulting in an unprecedented global crisis. The immunopathology of COVID-19 appears to be clearly associated with a dysregulated immune response leading to organ failure and death. Similarly, over two billion people worldwide are infected with helminth, with those living in low-middle-income countries disproportionately affected. Helminth infections have been shown to possess immunomodulatory effects in several conditions. Helminth co-infection in COVID-19 patients is one of the potential reasons for global attention to answer why COVID-19 severity is still lower in helminth endemic countries. Recent studies have shown that helminth endemic countries showed fewer cases and deaths so far and helminth co-infection might reduce the severity of COVID-19. Moreover, lessons from other diseases with helminth co-infection have been shown to substantially reduce vaccine efficacy that could also be implicated for COVID-19. This immunomodulatory effect of helminth has intended and unintended consequences, both advantageous and disadvantageous which could decrease the severity of COVID-19 and COVID-19 vaccine efficacy respectively. Herewith, we discuss the overview of COVID-19 immune response, immunomodulatory effects of helminth co-infections in COVID-19, lessons from other diseases, and perspectives on the efficacy of COVID-19 vaccines.

Keywords: COVID-19; SARS-CoV-2; helminth; immunomodulation; vaccine.

Figure 1

(A) illustrates the immune response in severe COVID‐19 characterized by activation of pro‐inflammatory cytokines mediated by TH1 cells leading to cytokine storm. (B) shows the immunomodulatory effects of helminth co‐infection in COVID‐19 patients. COVID‐19 patients have reduced TH1 response due to Th2 mediated helminth immune response. (C) shows the different available vaccine efficacy has not been assessed so far. Probably it could reduce the efficacy of the COVID‐19 vaccine based on lessons from other diseases including respiratory viruses. The figure is created with https://app.biorender.com