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May 7, 2005

Why it's hard to vaccinate against dengue

Westerners travelling to Southeast Asia have to worry about a number of different diseases that aren't common in the US and Europe. You can get vaccinated against yellow fever and take prophylactic antimalarial drugs, but there's one mosquito-borne disease that we can't do much about: dengue fever. If you're going to an area where dengue is endemic the best advice is to cover up and wear high DEET percentage insect repellent.

The reason we don't have a vaccine for dengue is rather interesting. There are four different dengue strains: DEN-1 through DEN-4. There's some evidence that if you are infected with one serotype and recover and then are infected with a second serotype, the infection is worse. As a result, a candidate vaccine needs to protect against all four serotypes. This turns out to be harder to make than a vaccine against just one serotype, though Acambis has a vaccine in development.

Credit: Linda Zadik alerted me to this issue.

Posted by ekr at May 7, 2005 9:42 PM | Filed under:

Comments

Check out one traveller's experience with dengue fever here -- http://www.honan.net/2003_02_01_archive2.php . It's awful, apparently: 'Harper later described the sensation as one of having someone scrape your bones with a knife, and that sounds about right.'

Of course, don't underestimate the market effects that tend to mean dengue is a low priority -- it affects predominantly people in SE Asia, who are poor and can't afford expensive medicine, so there's little impetus for a commercial drug company to perform R&D on anti-dengue drugs.

Posted by: Justin Mason at May 9, 2005 12:18 PM