Fresh Approach to Vaccines for Livestock
As the threat of bird flu looms over US farms, researchers are hustling to find ways to combat the outbreaks before they spiral into a human pandemic. One group of scientists has come up with an innovative strategy: they have developed the first mRNA vaccine for avian influenza in cattle. The initial results, shared on the preprint server bioRxiv this month, indicate that the experimental vaccine triggers a robust immune response and offers protection against infection in calves. However, it’s important to note that these findings have yet to undergo peer review.
The Need for Vaccines in Livestock
The fear of a bird flu pandemic has been escalating since the detection of the H5N1 avian influenza virus in dairy cattle in March 2024. Since then, over 1,000 dairy herds across 17 states in the US have been affected by the virus. Health authorities have connected 64 human infections and one fatality to the outbreak. This underscores the urgency for effective vaccines to prevent the spread of the virus from animals to humans.
A Different Approach to Vaccine Development
To create the cattle vaccine, Scott Hensley and his team drew from over ten years of research on seasonal bird flu mRNA vaccines. They took an existing vaccine candidate and swapped out its viral haemagglutinin gene with the gene from the new H5N1 virus found in dairy farms. This approach allows for easy adaptation, highlighting the value of mRNA-based vaccines. Previous studies by Hensley’s team have shown that the vaccine can protect against avian flu in ferrets, a common model for testing flu vaccines. In the latest study, the researchers vaccinated 10 calves and exposed them to milk from H5N1-infected cows after 49 days. The vaccinated calves exhibited lower levels of viral RNA compared to the unvaccinated ones, indicating a successful reduction in infection rates.
The Future of Livestock Vaccines
While the current results are promising, more research is needed to gauge the vaccine’s efficacy in lactating adult cattle, where much of the avian flu transmission occurs on dairy farms. Hensley’s team is already planning additional trials in lactating cows to address this gap. The US Department of Agriculture has approved several vaccine candidates for field trials this year, signaling a potential shift towards more preventive measures in livestock. Despite political challenges and concerns about the economic viability of cattle vaccines, experts like virologist Richard Webby emphasize the importance of exploring new strategies to curb infections, deaths, and economic losses in the livestock industry.
In the face of mounting challenges, the development of vaccines for livestock presents a glimmer of hope in the fight against avian influenza. While obstacles remain, the innovative approach taken by researchers like Scott Hensley offers a beacon of light in the quest to safeguard both animal and human health. As we navigate the complex landscape of infectious diseases, it becomes increasingly clear that creative solutions and collaborative efforts are essential to overcome the threats posed by emerging pathogens.
