U.S. CDC Under-Discloses Dengue Outbreaks

With the World Health Organization (WHO) and over 100 countries reporting Dengue cases in 2025 and classifying Dengue outbreaks as a grade 3 global emergency, the new U.S. CDC Travel Health Advisory appears to be under-highlighting this global health issue.

On March 20, 2025, the CDC only identified 16 countries with higher-than-expected Dengue cases among U.S. travelers returning from those countries.

Previously, the CDC stated that the Dengue virus was endemic in the U.S. territories of Puerto Rico, American Samoa, and the U.S. Virgin Islands. In the continental U.S., Dengue is frequently detected in Florida's Miami-Dade County.

As of March 21, 2025, the WHO/PAHO data dashboard indicates over 1.2 million Dengue cases and 348 related fatalities have already been reported this year in the Region of the Americas, which includes the United States.

In 2024, more than 13 million Dengue cases were reported in the Americas, making it the highest year on record.

The CDC stated today that international 'travelers should practice prevention measures for all areas with a risk of dengue, an acute febrile illness.'

An estimated 40%–80% of DENV infections are asymptomatic.

However, symptoms in perinatally infected neonates typically present during the first week of life and include fever, hemorrhagic manifestations, hypotension, and thrombocytopenia. 

A previous study found that 'compared to uninfected mothers, babies born to mothers with dengue are likely to have worse outcomes. Preterm birth and low birth weight are frequently observed in dengue-affected pregnancies, which can have serious effects on the health and development of the child.'

The CDC recommends that visitors to Dengue-risk areas prevent mosquito bites by using an EPA-registered insect repellent, wearing long-sleeved shirts and pants outdoors, and sleeping in rooms with window screens.

While many countries have authorized a second-generation Dengue vaccine (QDENGA) to reduce the number of mosquito-transmitted Dengue infections, this vaccine is unavailable in the U.S.

However, several Dengue vaccine candidates are conducting late-stage clinical trials, which could be authorized in the U.S. in the future.