First vaccine approved for all four Dengue virus serotypes in children and teens ages 9 through 16, but comes with major restrictions and controversy.
Image: Dengue Virus
Dengvaxia is the first vaccine approved by the FDA for prevention of dengue disease in patients ages 9 through 16 with a laboratory-confirmed prior history of dengue infection and live in endemic areas, including the U.S. Territories of American Samoa, Guam, Puerto Rico, and the U.S. Virgin Islands). It is effective against all four dengue virus serotypes.
Dengvaxia is a live, attenuated vaccine administered as three separate injections. The FDA stresses that Dengvaxia is not approved for individuals who have not had prior dengue fever, because in addition to symptoms resembling an initial infection of dengue virus, the wild-type virus is not included in the vaccine and could cause potential subsequent infections with a wild-type dengue virus could become more severe.
The initial dose of Dengvaxia is followed by two additional shots given 6 and 12 months after the first, respectively. The vaccine has already been approved in 19 countries, including the European Union.
The safety and effectiveness of the new vaccine was determined through three randomized placebo-controlled studies that enrolled approximately 35,000 individuals in dengue-endemic areas. The vaccine was determined to be about 76% effective in preventing symptomatic laboratory-confirmed dengue disease. Previously, Sanofi's vaccine has been plaqued by complicaitons, included deaths in the Phillipines that prompted legal acation against some Sanofi officials in early 2018.
The most common side effects to the vaccine reported during the trials were headache, muscle pain, joint pain, fatigue, injection site pain, and low-grade fever. Frequency of these effects were purportedly similar across Dengvaxia and placebo recipients and decreased after each subsequent dose of the vaccine.
Globally, as many as 400 million people are infected by dengue virus each year. The virus is transmitted by mosquitoes. According to the CDC, infection with one of the four virus serotypes does not protect against the others, and sequential infections put people at greater risk for dengue hemorrhagic fever and dengue shock syndrome.
Nearly all dengue cases reported in the 48 continental states were in people infected elsewhere, such as travelers or immigrants. These imported cases rarely result in secondary transmission. The last reported dengue outbreak in the 48 continental states was in south Texas in 2005. A small dengue outbreak occurred in Hawaii in 2001.