Human trials of a vaccine for Zika virus could begin as soon as this summer, the top US infectious disease researcher says, according to dpa. Dr Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, says work on a vaccine is already under way, but cautions any vaccine might not be widely available for several years. Because there are vaccines for similar types of viruses, such as dengue and yellow fever, Fauci says development should move fairly quickly. He says it should not take much time to determine if a vaccine is safe and effective and that an accelerated approval process for an immunization against the disease might be possible.