Superoxide Dismutase Inhibitors against Malaria, Leishmaniasis, and Chagas Disease: Systematic Review.

INTRODUCTION: Diseases caused by protozoa are one of the leading causes of death worldwide, especially in tropical regions such as Brazil. Chagas disease, leishmaniasis, and malaria are responsible for around 234 million cases and more than 400,000 deaths worldwide. Despite this scenario, drugs for these diseases have several limitations, which justifies the search for new treatments. Iron superoxide dismutase is a promising target for the drug design to treat patients with these diseases. It is a validated target and protects against oxidative stress. AIM: Thus, this systematic review aimed to synthesize evidence on the importance of superoxide dismutase in the drug design to treat patients with this protozoosis. METHODS: A search was performed for in vitro and in vivo studies, without publication and language restrictions, in MEDLINE (PubMed), LILACS (BVS), Science Direct, and EMBASE (Elsevier). Studies that pointed to the relationship between the reduction or increase in superoxide dismutase activity and the diseases were included. 23 studies were selected for the qualitative synthesis. RESULTS: The results showed that the inhibition or reduction of the enzyme activity decreases the degree of infection and reinfection and improves the results in treating these diseases. In contrast, the increase in activity caused a high degree of survival and resistance of the parasites. CONCLUSION: However, the overall quality of evidence is low and more studies with methodological rigor are provided.

Previous BCG vaccination is associated with less severe clinical progression of COVID-19.

BACKGROUND: BCG vaccination, originally used to prevent tuberculosis, is known to "train" the immune system to improve defence against viral respiratory infections. We investigated whether a previous BCG vaccination is associated with less severe clinical progression of COVID-19 METHODS: A case-control study comparing the proportion with a BCG vaccine scar (indicating previous vaccination) in cases and controls presenting with COVID-19 to health units in Brazil. Cases were subjects with severe COVID-19 (O2 saturation < 90%, severe respiratory effort, severe pneumonia, severe acute respiratory syndrome, sepsis, and septic shock). Controls had COVID-19 not meeting the definition of "severe" above. Unconditional regression was used to estimate vaccine protection against clinical progression to severe disease, with strict control for age, comorbidity, sex, educational level, race/colour, and municipality. Internal matching and conditional regression were used for sensitivity analysis. RESULTS: BCG was associated with high protection against COVID-19 clinical progression, over 87% (95% CI 74-93%) in subjects aged 60 or less and 35% (95% CI - 44-71%) in older subjects. CONCLUSIONS: This protection may be relevant for public health in settings where COVID-19 vaccine coverage is still low and may have implications for research to identify vaccine candidates for COVID-19 that are broadly protective against mortality from future variants. Further research into the immunomodulatory effects of BCG may inform COVID-19 therapeutic research.