MPI closely watching bird flu vaccine trials for cattle and poultry

4:57 pm on 26 May 2025

In December 2024 US authorities ordered a testing regimen for the nation's milk supply, amid increasing concerns over the H5N1 bird flu virus. Dairy cows in Ithaca, New York, on 11 December, 2024. Photo: AFP/ Michael M Santiago

MPI says it's not currently doing research into high pathogenicity avian influenza vaccines for cattle but it is "closely" watching overseas trials for both cattle and poultry.

The science journal Nature reported last week that US scientists were working on the first mRNA bird flu vaccine for cattle, using genetic code to help the body create antibodies to fight a disease, similar to the Covid-19 vaccine.

Bird flu is already rife across US poultry and cattle farms but the researchers are racing to contain those outbreaks before they spark a human pandemic. Since March last year the H5N1 virus has infected more than a thousand dairy herds across 17 US states.

MPI chief veterinary officer Dr Mary van Andel said MPI was following the US trial as well as other HPAI vaccine trials such as those in poultry.

The commercial use of any vaccine for HPAI would need to be considered against the risks posed to the industry, and only after consultation with the affected industry, she added.

"All vaccines for use in animals must be registered under the Agricultural Compounds and Veterinary Medicines (ACVM) Act before they can be imported to or manufactured, sold, or used in New Zealand. Similarly, vaccine trials conducted in New Zealand would also require ACVM authorisation before it can proceed. If a vaccine is needed to manage disease in New Zealand in future, either trial work to develop a new vaccine or registration of a vaccine available overseas are both options for consideration."

It was important to remember that New Zealand had never had a case of the bird flu strain H5N1 2.3.4.4b, and that HPAI was not a cattle disease, she said.

"The H5N1 strain of HPAI was detected in dairy herds in the United States following a spillover event in 2024. The US is the only country that has reported spillover to cattle worldwide, despite large seasonal outbreaks of this strain in other northern hemisphere countries."

A different strain of avian influenza, H7N6, was detected at a north Otago egg farm in December. About 200,000 chickens were culled across five sites after the outbreak.

Van Andel said MPI was working closely with international colleagues to learn everything it could from their experiences of H5N1 and it was keeping its industry partners informed.

"We are closely monitoring updates from both the United States Department of Agriculture (USDA) and the Centers for Disease Control and Prevention (CDC), as well as keeping in regular contact with the US Chief Veterinary Officer. Our industry and scientific communities have close linkages with colleagues in the US."

The CDC believed the current risk to the general public from bird flu viruses was low, she added.

However people with job-related or recreational exposure to infected birds or animals, including cows, were at greater risk of contracting H5N1.

"A small number of dairy farmworkers who were in close contact with infected cattle have been infected with the virus. These workers showed mild symptoms and recovered. HPAI H5N1 has not been detected or reported in beef cattle to date."

Van Andel said that if the strain of HPAI did arrive in New Zealand, the risk of transmission from birds to cattle or other livestock was low.

"We are working closely with the Department of Conservation, Health New Zealand Te Whatu Ora, the Ministry of Health and our industry partners to ensure we are ready should HPAI H5N1 be detected here. A key focus of this work is ensuring strong on-farm biosecurity practices are in place across the poultry industry and wider farming sector."