Andes Hantavirus Vaccine Advances – AMJ
Two investigational mRNA vaccines have successfully provided complete protection against the Andes hantavirus in a lethal animal model, according to research published in The Lancet. In a study using golden Syrian hamsters, a single intramuscular dose of either a modified or non-modified mRNA vaccine prevented overt disease and death following exposure to the virus.
How the Vaccine Performed
Researchers tested the vaccines—which encode the Andes virus envelope glycoproteins Gn and Gc—at doses of 25 μg, 5 μg, and 1 μg. Four weeks after receiving a single dose, the hamsters were challenged with 350 plaque-forming units of the Andes virus. While four out of five control animals succumbed to the infection by day 10, all vaccinated hamsters remained protected from clinical disease, regardless of the dose received.
The study, conducted by researchers at the University of Texas Medical Branch, found that no replicating virus was detected in the liver tissue of vaccinated hamsters when the study concluded on day 28. Additionally, the vaccines generated early, dose-dependent IgG antibody responses, with detectable levels appearing in subjects by day 14.
Did You Know?
The golden Syrian hamster is currently the only animal model available that effectively mimics the fatal hantavirus pulmonary syndrome observed in human patients.
Why This Research Matters
Unlike many other hantaviruses, the Andes virus is capable of human-to-human transmission through close contact with respiratory secretions. This unique characteristic makes it a significant public health threat, as demonstrated by the May 2026 outbreak on the MV Hondius cruise ship. That event resulted in 13 cases and three deaths, with passengers spreading across 23 different countries, which complicated international contact-tracing efforts during the 42-day incubation period.
Expert Insight:
Samantha Carter notes that the ability to achieve full protection with a single dose is a critical development for outbreak response. Given the rapid spread of the Andes virus, a vaccine that provides immunity within two weeks could be instrumental in managing high-risk contacts and preventing secondary infections in a way that multi-dose regimens cannot.
What May Happen Next
Because there are currently no FDA- or EMA-approved vaccines or preventive treatments for the Andes hantavirus, this study serves as a foundation for future clinical trials. A possible next step for researchers will be to determine the minimal effective dose and the scalability of these mRNA platforms. Further studies are also required to investigate the potential for these vaccines to act as post-exposure prophylaxis for individuals who have been recently exposed to the virus.
Frequently Asked Questions
What animal model was used to test these vaccines?
The research utilized female golden Syrian hamsters, which are the only animal model that closely replicates fatal hantavirus pulmonary syndrome in humans.
How quickly did the immune response develop?
Both the modified and non-modified mRNA vaccine platforms elicited IgG antibody responses by day 14 post-vaccination.
Were there any deaths among the vaccinated test subjects?
No. All vaccinated hamsters were protected from overt disease, whereas four of five unvaccinated control hamsters died or required humane euthanasia within 10 days of infection.
What potential role could these vaccine platforms play in managing future viral outbreaks in international travel hubs?