Guwahati: A recent study on the coronavirus conducted in Brazil found that there was a link between the outbreaks of dengue fever and the spread of COVID-19, suggesting that exposure to dengue provides some level of immunity against COVID-19.
...Dengue virus may provide immunity against COVID-19: Brazilian study
The study analysed the COVID-19 pandemic in Brazil and found a link between the spread of the coronavirus and past outbreaks of dengue fever