Epidemiology and burden of dengue fever in the United States: a systematic review

Background: Dengue is currently a global concern. The range of dengue vectors is expanding with climate change, yet United States of America (USA) studies on dengue epidemiology and burden are limited. This systematic review sought to characterize the epidemiology and disease burden of dengue within the USA.Methods: Studies evaluating travel-related and endemic dengue in US states and territories were identified and qualitatively summarized. Commentaries and studies on ex-US cases were excluded. MEDLINE, Embase, Cochrane Library, Latin American and Caribbean Center of Health Sciences Information, Centre for Reviews and Dissemination and Clinicaltrials.gov were searched through January 2022.Results: 116 studies were included. In US states, dengue incidence was generally low, with spikes occurring in recent years in 2013-16 (0.17-0.31 cases/100,000) and peaking in 2019 (0.35 cases/100,000). Most cases (94%, n = 7895, 2010-21) were travel related. Dengue was more common in Puerto Rico (cumulative average: 200 cases/100,000, 1980-2015); in 2010-21, 99.9% of cases were locally acquired. There were <50 severe cases in US states (2010- 17); fatal cases were even rarer. Severe cases in Puerto Rico peaked in 1998 (n = 173) and 2021 (n = 76). Besides lower income, risk factors in US states included having birds in residence, suggesting unspecified environmental characteristics favourable to dengue vectors. Commonly reported symptoms included fever, headache and rash; median disease duration was 3.5-11 days. Hospitalization rates increased following 2009 World Health Organization disease classification changes (pre-20 09: 0-54%; post-20 09: 14-75%); median length of stay was 2.7-8 days (Puerto Rico) and 2-3 days (US states). Hospitalization costs/case (2010 USD) were $14 350 (US states), $1764-$5497 (Puerto Rico) and $4207 (US Virgin Islands). In Puerto Rico, average days missed were 0.2-5.3 (work) and 2.5 (school). Conclusions: Though dengue risk is ongoing, treatments are limited, and dengue's economic burden is high. There is an urgent need for additional preventive and therapeutic interventions.