Throughout the United States, and indeed, most of the world, the preferred method of controlling H5 and H7 avian flu outbreaks in poultry has been the immediate quarantine and culling of infected or exposed birds.
Economically and socially, it can be a tough policy - particularly in countries where there are high levels of food insecurity or a high reliance on poultry for income or personal wealth.
So a handful of countries rely upon and use 99% of the worlds HPAI poultry vaccines -1) China (90.9%), 2) Egypt (4.6%), 3) Indonesia (2.3%), 4) Vietnam (1.4%), and 5) Hong Kong Special Administrative Region (< 0.01%). (cite Impact of vaccines and vaccination on global control of avian influenza by David Swayne).
With the exception of Hong Kong, all of these countries remain firmly entrenched with H5 viruses after more than a decade of avian flu vaccine use, and while it can be argued that these vaccines have saved millions of poultry from culling, there has also been a major downside.
Poultry vaccines don’t always prevent disease – sometimes they only mask the symptoms of infection, and that can allow viruses to spread stealthily, continue to reassort and evolve, and end up making matters worse (see Subclinical Highly Pathogenic Avian Influenza Virus Infection among Vaccinated Chickens, China).
The OIE has long maintained (see Does OIE recommend vaccination of animals to control the disease?) that vaccination of poultry cannot be considered a long-term solution to combating avian flu.
“Any decision to use vaccination must include an exit strategy, i.e. conditions to be met to stop vaccination”. – OIE on H7N9 Poultry Vaccines.
When HPAI H5 began heavily impacting North American poultry earlier this year there were calls from the poultry industry for the USDA to authorize use of a poultry vaccine (see The HPAI Poultry Vaccine Dilemma), but as noted there and in New Scientist: The Downsides To Using HPAI Poultry Vaccines, many officials are worried that the `cure' might turn out to be worse than the disease.
Yesterday the USDA's APHIS released the following statement indicating that current poultry vaccines are only 60% effective in protecting flocks, their use would greatly impact poultry exports - and that while research into the vaccine option will continue - additional criteria must be met before their use can be authorized.
USDA Will Review Vaccination Options As They Become Available
The U.S. Department of Agriculture continues to work closely with state and local partners and poultry producers who have been impacted by an outbreak of highly pathogenic avian influenza (HPAI). To date, USDA has deployed nearly 400 employees and contracted more than 2,100 personnel to work around the clock in states impacted by the outbreak. USDA has also identified more than $160 million in indemnity payments to date for producers whose flocks have been affected by HPAI, and we will continue to ensure adequate resources remain available to support a robust response. As part of USDA’s ongoing response, the Department evaluated the efficacy of current vaccine options for HPAI in addition to economic impacts of vaccination and has determined that, as it currently stands, additional criteria must be met before a vaccine can be approved for emergency use. Vaccines currently available are not well matched and do not meet a suitable level of efficacy. USDA also wants to be sure that the vaccine industry is in a position to produce enough doses to create an effective control measure. Finally, additional outreach with trading partners will be required to avoid significant market disruptions
In the weeks and months ahead, USDA will continue to support efforts to develop a more effective vaccine, assist poultry producers with strong biosecurity measures, indemnify producers for losses, and take aggressive action to maintain open markets for U.S. poultry based on international standards.
USDA will continue to encourage development of vaccines for HPAI and will approve vaccines as they are developed and evaluated. Currently, there is lack of a well matched, effective vaccine for HPAI from the public and private sectors. The vaccine currently available offers just 60 percent effectiveness in chickens, leaving 4 in 10 birds unprotected. The vaccine’s effectiveness in turkeys is still being studied. USDA’s Animal and Plant Health Inspection Service (APHIS) will reevaluate its vaccination decision as more effective vaccines are developed and ready for use, carefully considering both the efficacy of the vaccine and the potential trade impacts. If used, vaccines will be targeted in the states and poultry sectors where they can be most effective. Areas where quarantine, depopulation, and enhanced biosecurity cannot stop the spread of HPAI would be prioritized.
During this outbreak, USDA has preserved open markets to countries that account for approximately 84 percent of the value of U.S. poultry and poultry products (including eggs) in 2014. However, some significant trading partners have indicated that, if we began vaccinating, they would ban all U.S. exports of poultry and eggs until they could complete a risk assessment. Risk assessments are a common method of evaluating these types of requests, and often require a significant amount of time. The loss of these markets could potentially cost U.S. poultry producers billions in lost export sales that would need to be diverted to other export and domestic markets, with no clear timeline for reopening closed markets. USDA will continue to work closely with stakeholders and trading partners throughout the response.
The United States has the strongest AI surveillance program in the world so that the food supply and our people remain safe. No human infections with these viruses have been detected, and the U.S. Centers for Disease Control and Prevention considers the risk to the general public to be minimal. America’s food supply is safe. Properly prepared and cooked poultry and eggs are safe to eat.
As we continue to respond to this current outbreak, USDA and its partners continue to stress the importance of biosecurity measures for backyard and commercial poultry owners, underscoring five basic steps for responding quickly and decisively:
· Monitor region