An experimental vaccine against the dengue virus has been found to protect 100 percent of recipients in a clinical trial carried out by the USA's National Institute of Allergy and Infectious Diseases (NIAID). In the NIAID trial 21 people were vaccinated with TV003, while 20 received a placebo. Six months later they returned to be infected with a mild version of dengue-2. All 21 people who'd received the vaccine were protected against infection. All 20 members of the placebo group contracted dengue. A modified version of the vaccine is now being developed in an attempt to treat the related Zika virus....