Mosquito-borne diseases such as chikungunya, dengue fever, yellow fever and the Zika virus are spreading through urbanization, travel and climate change. A new generation of vaccines, tests and public health tools aims to stay ahead of these threats. The article was published in Nature Medicine online on March 9, 2026 with doi:10.1038/d41591-026-00014-6. These viruses pose an increasing risk due to environmental changes and human mobility. New vaccines and diagnostic tests are key to preventing the spread. Public health tools help control epidemics in high-risk areas.