Assessment of threat of concurrent SARS-CoV-2 and DENV infection in the COVID-19 pandemic in Brazil in 2020: diagnostic and immunological findings

Introduction The first peak of COVID-19 in Brazil was between April and May 2020, at a time of the year when outbreaks of other tropical diseases, such as dengue, would be expected. COVID-19 and dengue have similar pathogenesis. In general, both may lead to mild symptoms but may also cause severe and even fatal symptoms, especially in patients with comorbidities and probably in cases of overlapping infections. The general objective of this study was to assess whether, during the 2020 pandemic, there were cases of concomitant infection between SARS-CoV-2 and DENV. Methods For this, we evaluated the specificity and sensitivity of commercial serological anti-SARS-CoV-2 kits using plasma samples from patients with dengue and healthy donors recruited before COVID-19. In the case of confirmed cases of COVID-19/dengue, we evaluated the clinical evolution of these coinfected patients, compared with mono-infected patients; and quantified chemokines CCL2 and CXCL8 by ELISA in COVID-19 patients in order to correlate them with COVID-19/dengue severity and cases. Results and Discussion Our results showed that commercial IgA and IgG anti-SARS-CoV-2 kits presented high sensitivity and specificity. This allowed us to see a low rate of co-detection or coinfection between SARS-CoV-2 and DENV in Rio de Janeiro. Among the 57 COVID-19 patients, anti-DENV IgM was detected in five (8.8%). COVID-19/dengue coinfected patients showed no clinical worsening of COVID-19 and cases in which COVID-19 patients had previous exposure to DENV did not influence the clinical severity of COVID-19. Lastly, CCL2 and CXCL8 appeared to be good markers of COVID-19 severity and did not show increased levels in COVID-19/dengue cases.