As human cases of avian influenza slowly tick up amid the outbreak in U.S. dairy cattle, the Centers for Disease Control and Prevention (CDC) and Moderna have teamed up to design an mRNA vaccine for the current variant that successfully protected ferrets from succumbing to the virus.
The results were published in Science Translational Medicine on Dec. 18.
All unvaccinated ferrets exposed to the virus died from the disease, the authors reported. Vaccinated ferrets developed antibodies against the virus and had lower levels of virus in their respiratory tract after being infected.
Blood serum taken from immunized ferrets was also able to neutralize virus taken from a Texas patient who contracted bird flu after coming into contact with dairy cows in March 2024, the researchers wrote.
The CDC team was led by Bin Zhou, Ph.D., of the influenza division of the National Center for Immunization and Respiratory Diseases.
As bird flu cases creep up, including in a child in California who had no known contact with infected animals, fears of a potential future pandemic continue to brew.
There are currently three avian influenza vaccines approved in the U.S., one each from Sanofi, GSK and CSL Seqirus. In October, the Department of Health and Human Services' Center for the Biomedical Advanced Research and Development Authority gave these firms $72 million to bolster supplies of their shots.
However, these vaccines were designed for past variants of the virus, not the clade causing the current outbreak, known as 2.3.4.4b. The new mRNA vaccine from the CDC and Moderna is specifically designed to target 2.3.4.4b.
There are several other conventional vaccine candidates in development for 2.3.4.4.b, the study authors note, but, in the event of a pandemic, they may be difficult to rapidly produce and deploy. mRNA vaccines, on the other hand, are able to be scaled up quickly during an emergency.
There have been 60 confirmed human cases of the 2.3.4.4b bird flu virus in the U.S., with the disease also sweeping through 853 cow herds in 16 states. The virus has also ravaged numerous wild animal populations, including seals, sea lions and at least 315 species of birds.