Now this would be great news in the current fight against mosquito borne illness if it continues to pan out in the trials. A dengue fever vaccine currently in phase 3 development was 100% effective at preventing the disease, according to the results of a small clinical trial in which volunteers were inoculated and then given a weakened dose of the most difficult dengue virus serotype to prevent 6 months later.

Researchers used a human challenge model to test the efficacy of TV003, a live-attenuated tetravalent vaccine that was developed by the NIH’s National Institute of Allergy and Infectious Diseases and is currently undergoing a phase 3 trial in Brazil.

The study included 41 healthy participants — 21 who were given the vaccine and 20 assigned placebo. Each participant given the TV003 vaccine was protected from a weakened dose of dengue serotype 2 virus at 6 months, while all placebo group participants tested positive for the virus and developed mild symptoms such as rash and low white blood cell count, according to Kirkpatrick and colleagues.

Dengue Fever is the most common mosquito-borne virus in the world and is responsible for an estimated 400 million infections annually. Protecting against it, however, has been a challenge, particularly because an effective vaccine needs to prevent all four serotypes. A partially effective vaccine is dangerous, putting patients who were infected with one serotype at risk for more serious symptoms if they are infected with another.