GALVESTON — Researchers at the University of Texas Medical Branch published a study in The Lancet on June 11, 2026, detailing single-dose mRNA vaccines for Andes hantavirus. This development occurred after a recent outbreak of the virus.

In May, an Andes hantavirus outbreak took place aboard the Dutch cruise ship MV Hondius following its departure from Argentina. The outbreak resulted in the infection of 13 passengers and crew members, leading to three fatalities. Infected individuals can carry the virus for weeks before exhibiting symptoms, and the virus transmits directly between humans through coughing and close contact.

The research team evaluated a vaccine formulation for single-dose administration to address rapid outbreak response timelines. Previous research had initially developed a two-dose mRNA vaccine version that protected animals from the virus. Animal model testing demonstrated that a single vaccine dose prevented infection from a lethal viral dose. Test subjects receiving lower vaccine dosages remained asymptomatic and maintained stable body weights.

Michelle Meyer, PhD and lead author, said the vaccines triggered an immune response that created protective antibodies in as little as 14 days. She stated that when researchers looked at the tissues from vaccinated animals a month after infection, the virus was entirely gone. Alexander Bukreyev, PhD and head of the Laboratory of Viral Pathogenesis and Vaccine Development at UTMB, said that if given quickly to high-risk contacts during an outbreak, such as the Andes virus situation on the cruise ship, the vaccines could theoretically jump-start immune systems fast enough to intercept the virus, stopping its replication and preventing people from getting sick or spreading it further. The extended progression timeline of the virus allows the vaccine to potentially function as a post-exposure intervention. The University of Texas Medical Branch is utilizing National Institutes of Health funding to advance the vaccines into human clinical trials.

No independent assessment was available for this report.