The USDA’s Animal and Plant Health Inspection Service (APHIS) recently awarded contracts to two companies to produce highly pathogenic H5 avian influenza vaccines for the National Veterinary Stockpile, should the virus resurface in the United States and vaccination is approved by the agency.

Ceva’s Vectormune AI and Harrisvaccines’s Avian Influenza Vaccine, RNA, were the two vaccines approved for production the contracts. Representatives from both companies have offered further details on their products and how they were designed to work.

However, both companies stated they will supply their vaccines to APHIS, which could choose to use the vaccines differently than how the product labels recommend.

On which birds may vaccines be administered?

According to Kristi Moore Dorsey, Ceva vice president of research and development, the label for Vectormune AI calls for use in day-old chicks. It could be applied to broilers, layers and turkeys if approved by the USDA.  

Harrisvaccines’ Avian Influenza Vaccine, RNA, has been tested for use in day-old chicks and adult hens.

“We believe it can be used at any age in chickens, and we’re looking at that in turkeys,” said Joel Harris, head of sales and marketing for Harrisvaccines.

Harris adds that tests have also been conducted for the product’s use in ducks.

Ceva avian flu

Ceva's Vectormune AI vaccine is designed to be administered to day-old chicks. | Ceva

How and how often could be vaccines be administered?

Both vaccine products have been proven to provide birds with immunity to avian influenza with a single dose, according to officials with the companies.

Vectormune AI’s label directs users to administer the vaccines subcutaneously in the back of the neck, according to Dorsey.

Harrisvaccines RNA particle vaccine is designed for subcutaneous injection in the wing web or for intermuscular injection in the breast, although the wing web method is preferred, according to Dr. Hank Harris, CEO and founder of Harrisvaccines. The company is also exploring ways to make the product injectable into eggs, as well as have it administered by way of spray or in the water.

Tests show the level of vaccines’ effectiveness

Ceva’s licensure data showed Vectormune AI to be 100 percent protective when given at one day of age by the subcutaneous route in both specific pathogen free (SPF) and maternal antibody-positive birds.

“In addition, Ceva has generated a significant amount of research and field data internationally for this product. This vaccine has been tested multiple times, in various conditions and various types of chickens, against a wide range of H5 type highly pathogenic avian influenza virus, with protection levels ranging from 100 percent to 60 percent,” said Dorsey.

Joel Harris noted that studies have shown the Harrisvaccines product has an efficacy rate of 93 percent in day-old chicks and a 95 percent efficacy level in adult layer hens.

Most of the tests for Harrisvaccines’ Avian Influenza Vaccine, RNA, have been done on broilers and layers, while testing for turkeys are being done at the USDA National Veterinary Services Laboratory in Ames, Iowa. Testing on ducks is also being done at the USDA’s Southeast Poultry Laboratory, Athens, Georgia, which is also where testing on chickens was conducted.

Possibilities for other vaccine contracts

APHIS has not approved the use of vaccine to respond to avian influenza and states that any decision to use vaccination in a future highly pathogenic avian influenza outbreak would require careful consideration of the efficacy of the vaccine, any impacts of using HPAI vaccine in the field, and the potential trade impacts.

While to date, only two vaccines have been given licensure and awarded contracts for the stockpile, APHIS is continuing to seek requests for proposals (RPFs) for vaccine manufacturers with the interest and capability to supply a variety of Eurasian (EA) H5 vaccines in sufficient numbers to establish the emergency stockpile. 

APHIS will continue to issue RFPs for vaccine manufacturers on a quarterly basis through September 2016, to allow additional products to be developed and considered for the stockpile should an outbreak occur. Information about future RFPs and awarded contracts will be available on the APHIS website.