Overnight MPR (Minnesota Public Radio) published a story on the desire of many turkey producers to vaccinate their flocks against the HPAI H5 avian flu this fall (something which has yet to be approved by the USDA), while at the same time examining a number of `downsides’ to introducing avian flu vaccines to North American flocks.
The report is a good read, features comments by CIDRAP Director Dr. Michael Osterholm and University of Minnesota avian flu researcher Dr. Carol Cardona (among others) - and unlike most media stories this summer - explores more than just the negative impact that vaccine use would have on poultry exports.
While the most immediate concern expressed by government officials has been the refusal of some countries to import vaccinated poultry products – which could cost the poultry industry billions of dollars in lost revenue – there are other serious concerns regarding AI vaccine use.
- First, China, Egypt, and Indonesia – the three biggest consumers of HPAI poultry vaccines (cite Impact of vaccines and vaccination on global control of avian influenza by David Swayne) – are just as firmly entrenched with bird flu today as they were a decade ago when the decision was made to use them.
- Worse, the diversity of HPAI flu viruses has grown markedly while using AI vaccines, a phenomenon we explored last month in PLoS Bio: Imperfect Poultry Vaccines, Unintended Results and last April in New Scientist: The Downsides To Using HPAI Poultry Vaccines.
- In last November’s EID Journal: Subclinical HPAI In Vaccinated Poultry – China researchers found evidence to suggest that `imperfect’ vaccines were driving the evolution of new clades, and and the creation of subtypes, while last February, in Recombinant H5N2 Avian Influenza Virus Strains In Vaccinated Chickens – its authors reaffirmed that `AIVs can continue genetic evolution under vaccination pressure’.
Simply put, while vaccines can often protect poultry against illness - with increasingly diverse and rapidly evolving avian flu viruses - they cannot always prevent infection. The end result being that subclinical infections can go undetected, viruses continue to circulate, and new variants or reassortants continue to emerge.
Historically, the USDA has remained focused on prevention and containment when it comes to HPAI viruses in this country, and it is obvious they would rather not to have to go down the avian flu vaccine path if they can avoid it.
They will, however, come under tremendous industry pressure to authorize their use if avian flu returns with a vengeance this fall or winter. While there are probably situations where the geographically limited, temporary use of a poultry vaccine might be advisable - the track record of large scale reliance on AI poultry vaccines hasn’t been enviable.
Follow the link below to read the whole MPR article. Highly recommended.
Minnesota Board of Animal Health staff tested chickens in a backyard flock for avian influenza in April 2015. While initial tests in chickens are encouraging, the bird flu vaccine has plenty of downside. Courtesy Minnesota Board of Animal Health
Minnesota turkey farmers are clamoring to vaccinate their flocks this fall against avian influenza. But while initial tests in chickens are encouraging, experts say the vaccine has plenty of downside.
Minnesota has lost more than 9 million turkeys and chickens to avian flu and the requirement to kill surviving birds to stop the disease from spreading. By the time the virus retreated in early June, the flocks of 108 Minnesota poultry farms had been wiped out. So there's not much debate among the state's turkey farmers about whether a vaccine should be used if the deadly virus returns.
"In Minnesota we're pretty much unanimous that this is something we would use, if we have it," said Steve Olson, executive director of the Minnesota Turkey Growers Association.