Does First Generation Dengue Vaccine Deliver Protection

In 2016, the Philippine Department of Health implemented a dengue vaccination program with a first-generation dengue virus (DENV) vaccine, which was discontinued because of safety concerns. 

A recent study assessed the relative risk of developing virologically confirmed dengue among children who did or did not receive a single dose of the Dengvaxia® (CYD-TDV) vaccine by previous DENV infections at baseline classified as none, one, and two or more infections.

This study published by The Lancet Infectious Diseases on March 22, 2024, concluded that a single dose of the Dengvaxia vaccine was ineffective in protecting against DENV among patients who had no prior history of infection or had only one prior infection.

One dose conferred significant protection against hospital admission for virologically confirmed dengue among participants who had two or more previous DENV infections at baseline during the first three years (70%, 95% CI 20–88; p=0·017) and the entire follow-up period (67%, 19–87; p=0·016).

However, young patients exposed to two or more prior DENV infections showed a significant decrease in the risk of DENV infection after receiving the first Dengvaxia dose. This protection continued for up to three years after the vaccination.

Since the study assessed the effect of only a single dose, this study's findings cannot inform public health officers' decisions on vaccination. However, the findings have implications for children who receive an incomplete vaccination regimen, and should prompt more detailed analyses in future trials on dengue vaccines.

Dengue outbreaks are a global health problem in 2024.

As of March 2024, the CDC has reported over two million dengue cases worldwide, with over 500 deaths. The U.S. CDC has issued a global alert regarding dengue outbreaks in various countries.

A person infected via a mosquito bite will have no symptoms or show clinical manifestations ranging from dengue fever, a mild flu-like syndrome, to dengue shock syndrome, a life-threatening condition.

The CDC recommends speaking with a healthcare provider before visiting dengue-endemic areas like Puerto Rico to discuss vaccination and treatment options.