Background: Newly designed COVID-19 vaccines were approved and administrated worldwide. However,
the interaction between parasitic infections and COVID-19 vaccines and their efficacy is still obscure.
Objective: To correlate cytokines (TNF-α and IL-4) levels with COVID-19 vaccine administration in
patients with concomitant parasitic infections. A secondary objective is to assess the impact of parasitic
infections on COVID-19 efficacy.
Subjects and Methods: The study included 128 patients divided into 2 groups according to an answered
questionnaire, and routine laboratory investigations (stool, urine and blood film examination). Both
groups included vaccinated (received full doses of COVID-19 vaccine within 6 months of sample collection),
and non-vaccinated. A third matching group was recruited as control apparently health participants, i.e.,
neither parasitic infected nor received COVID-19 vaccines. Molecular detection of cytokines (TNF-α, and
IL-4) gene expression was performed for all study samples using real-time PCR.
Results: In comparison to the control group, there was up-regulation of TNF-α in patients with parasitic
infection, whether vaccinated or not. According to parasitism, IL-4 showed different gene expression.
In case of helminthic infections, it was up regulated in non-vaccinated patients, and down regulated in
vaccinated patients. Meanwhile, it was down regulated in patients with protozoal infections whether
vaccinated or not.
Conclusion: COVID-19 vaccinated patients with concomitant helminthic infections are susceptible to
reduced vaccine efficacy. Generally speaking, parasitism however, could provoke cytokine storm syndrome.