The first vaccine in the world against dengue virus has shown it protects against three of four strains of the virus. Those results were from a trial that took place in Thailand, said the maker of the vaccine this week. The vaccine was able to generate antibody responses against the four strains, but for an unknown reason, one of the strains succeeded in infecting children who had been given the vaccine. Scientists currently are trying to determine why that happened. In the mean time, a trial of much larger proportion, which involves nearly 31,000 children and adults, is currently underway in 10 different countries in Latin America and Asia.
Close to three billion people, the majority in regions around the equator are vulnerable to deadly infections by the virus, which mosquitoes carry. It is only common in the U.S. in Hawaii and Puerto Rico, although Florida had an outbreak recently. Over 230 million people are estimated to be infected annually. Up to 80% of those who become infected do not even develop any symptoms, but over 2 million, the majority being children, develop dengue hemorrhagic fever a severe form of the sickness. Symptoms can include headache, fever, joint and muscle pains. Infections can be deadly and no specific treatment for the infection has been established.
Dengue is of the same genus as that of the West Nile, St. Louis encephalitis and Yellow Fever viruses. The virus has four strains. Getting infection with one strain will provide immunity for life against that particular strain, but just a short amount of immunity against the viruses’ other three strains.