Background: In developing countries, schistosomiasis is a serious illness. Schistosomiasis continues to reach new areas despite coordinated management strategies. Therefore, to increase vaccination effectiveness, additional antigens and adjuvants must be discovered. Additionally, the Coronavirus Disease 2019 (COVID-19) vaccine that has already been developed must be used to combat other illnesses that are currently present. The ongoing study goal was to evaluate the COVID-19 vaccine's impact on experimentally Schistosoma (S.) mansoni-infected mice.
Main body: Seventy-two mice were used in that research. The mice were placed into eight groups, each with eight mice, except for two chronic groups, each included twelve mice. Two intramuscular injections of the vaccine were administered at intervals of three weeks. Two weeks following the first dosage of the vaccine, S. mansoni infection was performed. To assess the impact of the COVID-19 vaccination on S. mansoni infection, tests were performed on worm load, hepatic and intestinal ova count, oogram pattern, hepatic granuloma number and diameter, and Masson's trichrome for fibrosis. To evaluate toxicity and morbidity; urea, creatinine, and liver enzymes were performed. To measure the immunological effects; interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-4, and IL-17 serum concentrations were measured. For further analysis, immunohistochemical staining on liver sections for detection of transforming growth factor beta (TGF-β) and alpha-smooth muscle (α-SM) was performed. Results revealed that the COVID-19 vaccination was linked to a considerable reduction in tissue egg load and worm burden along with an increase in the percentage of eggs that were dead. The number and diameter of the granulomas were significantly reduced. Additionally, a lower proportion of fibrosis was seen on Masson's trichrome-stained sections. Decreased schistosomiasis-related morbidity and reduction in the H scores of TGF-β and α-SM in the tissues were also observed.
Conclusion: The COVID-19 vaccine reduces the worm burden, pathology, and morbidity of S. mansoni. These findings indicated that more research into the effects of various COVID-19 vaccines on schistosomes is necessary both alone and in conjunction with other Schistosoma vaccines.