Distinguishing non severe cases of dengue from COVID-19 in the context of co-epidemics: a cohort study in a SARS-CoV-2 testing center on Reunion island

Joubert, Antoine; Andry, Fanny; Bertolotti, Antoine; Accot, Frederic; Koumar, Yatrika; Legrand, Florian; Poubeau, Patrice; Manaquin, Rodolphe; Gerardin, Patrick; Levin, Cecile

BackgroundAs coronavirus (COVID-19) is spreading globally, several countries are handling dengue epidemics. As both infections are deemed to share similarities at presentation, it would be useful to distinguish COVID-19 from dengue in the context of co-epidemics. In this aim, we performed a cohort study to identify predictors of both infections. MethodsAll the subjects suspected of COVID-19 between March 23 and May 10, 2020, were screened for COVID-19 within the testing center of the University hospital of Saint-Pierre, Reunion island. The screening consisted in a questionnaire surveyed in face-to-face, a nasopharyngeal swab specimen for the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) reverse transcription polymerase chain-reaction and a rapid diagnostic orientation test for dengue. Factors independently associated with COVID-19 or with dengue were sought using multinomial logistic regression models, taking other febrile illnesses (OFIs) as controls. ResultsOver a two-month study period, we identified among 80 COVID-19, 60 non-severe dengue and 872 OFIs cases, delayed presentation (>3 days) since symptom onset (Odds ratio 1.89, 95% confidence interval 1.4-3.40), contact with a COVID-19 positive case (OR 3.81, 95%CI 2.12-6.82) and anosmia (OR 8.27, 95%CI 4.39-15.54) as independent predictors of COVID-19, body ache (OR 6.83, 95%CI 2.84-16.41), headache (OR 5.38, 95%CI 1.81-15.94) and retro-orbital pain (OR 7.45, 95%CI 3.17-17.50) as independent predictors of dengue, while smoking was less likely observed with COVID-19 (OR 0.27, 95%CI 0.10-0.74). ConclusionsAlthough prone to potential biases, these data suggest that non-severe dengue may be more symptomatic than COVID-19 in a co-epidemic setting with higher dengue attack rates. 40-word summary of the articles main pointIn the COVID-19 dengue co-epidemic setting of Reunion island, dengue was found more symptomatic than COVID-19 and associated with body ache, headache and retro-orbital pain, while COVID-19 was found associated with contact, anosmia, delayed presentation and absence of active smoking.