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In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week.

December 1, 2025 by Hannah Sachs-Wetstone

Newly published data shows that the antiviral compound mosnodenvir, developed by Johnson & Johnson, is effective at preventing dengue infection in people deliberately exposed to the virus, which affects millions around the world every year. There are no approved treatments for dengue, and available vaccines face production and efficacy issues. Despite its promise, the future development of the drug is in flux after Johnson & Johnson halted all its infectious disease work last year. Negotiations are underway to find another company to advance the drug, which, if it continues to demonstrate potential, could be used to protect large populations during epidemics, as well as to protect people traveling to endemic areas. 

Last week, Brazil’s regulatory agency approved the Butantan Institute’s Butantan-DV vaccine for dengue for people aged 12 to 59. The vaccine demonstrated high efficacy in clinical trials against dengue, which causes millions of cases globally, with a substantial burden faced by Brazil. The single-dose vaccine could offer faster and simpler vaccination campaigns compared to existing vaccines. Brazil signed an agreement with WuXi Biologics to deliver approximately 30 million doses of the vaccine in the second half of next year. 

The results of a human-challenge Phase 2a trial published last week found that an mRNA vaccine was more effective against symptomatic and febrile flu compared to the conventional vaccine. Another trial published last week also found that mRNA flu vaccines were more effective than conventional vaccines. Beyond effectiveness, mRNA vaccines can also be made more quickly, helping ensure that vaccines match circulating flu strains. Additional studies that include older people, those with coexisting illnesses, and school-age children, who face elevated risks, will be required to ensure broad efficacy across populations. 

About the author

Hannah Sachs-WetstoneGHTC

Hannah supports advocacy and communications activities and member coordination for GHTC. Her role includes developing and disseminating digital communications, tracking member and policy news, engaging coalition members, and organizing meetings and events.Prior to joining GHTC,...read more about this author