The Journal of Infectious Diseases | 2026
11 April 2026
In a new perspective published in The Journal of Infectious Diseases , infectious disease expert Dr. Gregory Gray highlights the vaccination of dairy herds as one of the most vital steps the United States can take to curb the H5N1 epizootic. Gray contends that because dairy cattle have become an evolutionary "training ground" for mammalian adaptation, proactive vaccination is essential to reduce pandemic risk.
Gray and his colleagues argue that after four years of "failed aggressive livestock biosecurity interventions," the H5N1 epizootic continues to rage across the United States. Since 2024, the virus has spread to more than 1,086 dairy herds across 19 states. This ongoing outbreak has resulted in the culling of over 190 million poultry and has imposed a massive economic burden, estimated at $14.3 billion, or 0.06% of the U.S. real GDP.
Beyond the economic impact, the authors highlight significant public health risks. They describe dairy cattle as an evolutionary "training ground" for mammalian adaptation. With 71 confirmed human cases and 2 deaths reported to date, each transmission event provides the virus an opportunity to acquire mutations that could enable efficient human-to-human spread, potentially leading to a pandemic.
The commentary emphasizes that a vaccination program is both feasible and necessary for several reasons:
-Studies show that cattle naturally or experimentally infected with H5N1 can develop durable, sterilizing immunity that protects against reinfection for over a year.
-Early trials of rabies virus-vectored vaccines in cattle have shown protective neutralizing antibody titers for at least 200 days.
-These new platforms function as "DIVA" vaccines, which allow officials to differentiate infected animals from vaccinated ones, reducing barriers to international trade and surveillance.
-Lowering the viral burden in dairy herds would likely reduce transmission to nearby poultry operations and humans.
For such a program to be economically viable, the authors suggest a benchmark cost of $5 or less per dose. They also call for the development of low-cost, high-throughput serological assays to monitor herd immunity and the continuous tracking of viral evolution to guide vaccine updates.
Ultimately, the authors conclude that it is now imperative to develop effective H5N1 vaccines and diagnostics for dairy cattle to protect the livestock industry, food security, and global human health.
