Dengue Vaccine Gets the Nod
Rebecca Voelker, MSJ
JAMA. 2019;321(21):2066. doi:10.1001/jama.2019.6886
The FDA has approved the first vaccine to prevent disease caused by all 4 dengue virus serotypes. The vaccine is indicated only for children and teens aged 9 to 16 years living in endemic areas who have had a previous, laboratory-confirmed dengue infection.

Although dengue cases are rare in the continental United States, the disease is found regularly in American Samoa, Puerto Rico, Guam, the US Virgin Islands and in Latin America, Southeast Asia, and the Pacific Islands. More than one-third of the global population lives in areas at risk of infection; up to 400 million infections occur annually.

In 3 clinical trials involving about 35 000 people in endemic areas, the vaccine was determined to be approximately 76% effective in youths aged 9 to 16 years who had a previous, laboratory-confirmed infection. The indication for the vaccine is limited to those with a previous infection because the first one is generally asymptomatic or causes only mild symptoms that can be mistaken for the flu. But a second infection with another serotype can lead to severe, potentially fatal disease. So the restriction reserves the vaccine for youths at greater risk of severe symptoms.

In addition, the vaccine is an attenuated live-virus formulation that, by stimulating antibody production, can act like a first dengue infection. Anyone who is vaccinated without a previous infection then has a higher risk of developing severe symptoms from a subsequent infection.

In the Philippines, a 2016 school-based vaccination program was associated with the deaths of at least 3 school children, according to a preliminary government investigation. Although dengue is widespread in the Philippines, it’s possible that some children had never been infected but were vaccinated. A subsequent infection may have led to severe disease.

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