September 20, 2024

 

USDA moves forward with H5N1 vaccine trials for dairy cattle

The US Department of Agriculture (USDA) has taken a significant step towards the approval of an H5N1 avian flu vaccine for dairy cattle, with the possibility of the vaccine being available by the first quarter of next year, FarmProgress reported.

 

Highly pathogenic avian influenza (HPAI) in dairy cattle was first detected in March this year, and since then, 203 cases have been confirmed across 14 states.

 

In a recent notice, the Centre for Veterinary Biologics (CVB) authorised H5N1 field vaccine studies outside of containment facilities under strict biosecurity protocols. This decision allows vaccine developers to conduct studies more quickly and could expedite the USDA's approval process for the vaccine.

 

Gary Bosch, executive vice president of Medgene, a South Dakota-based vaccine developer, stated that the company could begin field studies on a vaccine within weeks, pending approval of its testing protocol by the CVB.

 

Previously, H5N1 vaccine trials were limited to biosecurity level-3 laboratories, the second-highest level of biosecurity in the US, where only a few labs are equipped to handle cattle.

 

"The notice allows non-replicating vaccines to be tested in the field without the need to discard milk or meat from the animals," Bosch explained. "This opens up a better pathway for testing the vaccine in lactating animals, although it doesn't guarantee approval for sale or distribution."

 

Medgene uses a "plug-and-play" vaccine development process, which allows researchers to quickly develop vaccines by inserting genes into a vector, like using pods in a beverage maker. The company has previously developed vaccines for rabbit haemorrhagic disease and various pig diseases.

 

As of June 12, 2024, at least 24 companies, including Zoetis and Merck Animal Health, have been working on avian flu vaccines for cattle. Zoetis began developing its vaccine earlier this year, while Merck has not disclosed its pipeline but confirmed ongoing research in the area.

 

At the recent Farm Progress Show, US Agriculture Secretary Tom Vilsack announced that the department had approved its first field trial for avian flu in dairy cattle. He noted that this marks the next step in developing a vaccine, which could be available in the "near term."

 

Bosch indicated that the best-case scenario for Medgene's vaccine would be a release in the first quarter of next year, depending on the success of field trials and government approval.

 

California has recently emerged as a hotspot for HPAI in dairy cattle, with two cases confirmed on September 10, 2024, three cases on September 9, and three on August 30. Michigan also reported a case on September 9, bringing its total to 29 cases since March. Colorado remains the state with the highest number of confirmed cases, with 64.

 

Unlike the strain of HPAI that affects poultry, which spreads through wild birds, the H5N1 2.3.4.4B sub strain B3.13 affecting cattle is believed to spread through human contact with sick animals, contaminated farm equipment, and asymptomatic infected cattle.

 

While the disease has led to mass poultry depopulation, its impact on cattle has been less severe. Symptoms in dairy cows include reduced milk production, thickened milk, decreased feed intake, and lethargy. However, most cows recover from the disease.

 

Despite the cows' recovery, questions remain about the long-term impact on their productivity. Bosch pointed out that while some producers may believe the virus will burn out, the risk of it reasserting itself remains, and the long-term impact on milk production may justify vaccinating herds to prevent the disease.

 

-      FarmProgress