DEC 31, 2015

World's First Dengue Fever Vaccine Approved in 3 Countries

WRITTEN BY: Xuan Pham
Dengue fever is a mosquito-borne disease that’s prevalent in tropical locations like Latin America, Southeast Asia, and the Pacific islands. Up until now there was no vaccine against the dengue virus. But the first ever developed vaccine has swiftly gotten approval in three countries, with more approvals expected soon.
The vaccine against the dengue virus, Dengvaxia, was developed and is manufactured by the French pharmaceutical giant Sanofi.
 
"It's a major step in the prevention of dengue and for public health," Olivier Charmeil, head of Sanofi's vaccines division, said in a statement.
 
Dengue fever is caused by any one of four related dengue virus that’s transmitted through mosquito bites. Once infected sufferers experience painful flu-like symptoms that, in severe cases, have the potential to cause life-threatening dengue hemorrhagic fever or dengue shock syndrome. The Centers for Disease Control and Prevention estimates that as many as 400 million people are infected yearly; about 22,000 people die from it.
 

 
The Dengvaxia vaccine is actually based on an attenuated form of the yellow fever virus. This is because both viruses are very similar, sharing the same Genus. Geneticists then tweaked the yellow fever virus version to make it express the four types of dengue proteins. Once immunized with this modified virus, the host should be able to make antibodies against all four forms of dengues. Reportedly, Sanofi's research and development on the Dengvaxia vaccine took 2 decades and cost in excess of $1.6 billion.
 
Mexico was the first to approve the vaccine on December 11, 2015. Then last week on December 22, 2015 Philippines became the first Asian country to approve the vaccine. Dengvaxia recently secured the green light in another country: Brazil, where over 1.4 million cases of dengue fever were reported in 2015 alone. The vaccine is currently being reviewed in about 20 other countries in Asia and Latin America.

The United States had it’s own scare with Dengue fever earlier this year when cases appeared in Hawaii and Florida. In Puerto Rico the disease is already considered endemic.
 
Dengvaxia is a not a flawless vaccine. Clinical trials show that it works to prevent the disease in about 60% of cases; this means that the vaccine has a one third chance of being ineffective. Furthermore, the efficacy of the vaccine is restricted to people between 9 to 45 years old. This excludes young children and the elderly, arguably the populations most at risk who need a dengue vaccine the most. But an imperfect vaccine may be better than no vaccine at all.

Sources: Scientific American, Yahoo News