Previous dengue infection and mortality in COVID-19.

We studied 2351 participants with COVID-19, 1177 (50%) reported previous dengue infection. Those without previous dengue had a higher risk of death (hazard ratio: 0.44; 95% CI: 0.22 to 0.89; p = 0.023) in 60-day follow-up. These findings raise the possibility that dengue might induce immunological protection against SARS COV-2.