There have been more than 130 million cases of SARS-CoV-2 infections to date worldwide, yet another global pathogen--the Aedes mosquito-borne dengue virus--saw a record number of over 400 million cases in 2019. But vaccine development has been challenging due to the need to protect equally against all four dengue strains. The discovery of new possible biomarkers to predict clinical and immune responses to dengue virus infection, published on May 24, 2021 in Nature Communications, could be critical to informing future vaccines. The open-access article is titled “Immunotranscriptomic Profiling the Acute and Clearance Phases of a Human Challenge Dengue Virus Serotype 2 Infection Model.” As with SARS-CoV-2 infection, the effects of dengue virus infection can range from asymptomatic to severe disease that can be fatal. Climate change has expanded the viruses' geographic distribution far beyond tropical areas like Southeast Asia and Latin America to the southern U.S. and Europe. Only one vaccine, Dengvaxia, has been approved for a subset of at-risk individuals in endemic areas.