Researchers at The University of Texas Medical Branch (UTMB) have developed a single-dose vaccine that provided 100% protection against the lethal Andes hantavirus in animal models. According to a study published in The Lancet, the mRNA-based vaccine successfully prevented illness even when administered at a fraction of the standard dosage, offering a potential emergency tool for containing human-to-human outbreaks.
How does the Andes virus differ from other hantaviruses?
Most hantaviruses are transmitted to humans through contact with the waste or saliva of infected rodents, but the Andes virus is unique. As noted by the research team at UTMB, the Andes virus can spread directly between people through coughing and close contact. This respiratory transmission capability makes it a more significant public health threat than its rodent-borne cousins. The virus gained international attention following an outbreak on the Dutch cruise ship MV Hondius, which resulted in 13 infections and three deaths among passengers who had recently departed from Argentina.
Unlike many other viral threats, the Andes virus can remain in a person’s system for weeks before symptoms appear. This long incubation period complicates contact tracing, as individuals can travel across international borders while unknowingly carrying the infection.
Why is a single-dose vaccine critical for outbreak response?
Standard vaccination protocols often require multiple doses spaced weeks apart, a timeline that is often incompatible with the rapid spread of an international outbreak. Lead author Dr. Michelle Meyer reported that the team’s mRNA vaccine triggered a powerful immune response with protective antibodies appearing in as little as 14 days. By shifting from a two-dose regimen to a single shot, the researchers created a tool that could theoretically be used as post-exposure prophylaxis. Dr. Alexander Bukreyev, head of the Laboratory of Viral Pathogenesis and Vaccine Development at UTMB, stated that the vaccine could jump-start an immune system fast enough to intercept the virus in high-risk contacts, preventing further transmission.
What are the next steps for human clinical trials?
UTMB is currently working to fast-track these vaccines into human clinical trials with support from the National Institutes of Health. The recent study, which included contributions from researchers such as Dr. Ivan V. Kuzmin, Emmett Dews, and Matthew Hyde, demonstrated that vaccinated animal models remained completely healthy without weight loss or detectable viral presence one month after exposure. This definitive protection, even at reduced dosages, provides a strong baseline for regulatory approval processes.
mRNA vaccines work by providing cells with the instructions to create a harmless piece of the virus, which then teaches the immune system to recognize and attack the actual pathogen if it enters the body. Because they are faster to design and produce than traditional vaccines, they are becoming the primary tool for responding to emerging viral threats.
Frequently Asked Questions
- Is the Andes vaccine currently available to the public?
No. The vaccine has only been tested in animal models. It must undergo human clinical trials before it can be authorized for public use. - How is the Andes virus transmitted?
Unlike other hantaviruses, it is known to spread through person-to-person contact, specifically through respiratory droplets like coughing. - Who led the development of this vaccine?
The research was led by Dr. Alexander Bukreyev and Dr. Michelle Meyer at The University of Texas Medical Branch.
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