DES MOINES, Iowa >> Scientists have developed a vaccine strain that has tested 100 percent effective in protecting chickens from bird flu and testing is underway to see if it also protects turkeys, U.S. Agriculture Secretary Tom Vilsack told the House Agriculture Committee at a hearing on Wednesday.

If it does, the agency plans to quickly license it for widespread production and is seeking funding from the Office of Management and Budget to stockpile it nationally.

"Hopefully we’ll be able to get a lot of folks working collaboratively together and we stockpile enough so that if this does hit and hits us hard we’re in a position to respond quickly," Vilsack said.

Developing a vaccine targeted to the H5N2 virus that has killed 48 million birds since early March in 15 states, including hardest-hit Iowa, Minnesota and Nebraska, is one aspect of planning for a potential recurrence of the bird flu, Vilsack said.

Scientists believe the virus was spread through the droppings of wild birds migrating north to nesting grounds. They’re concerned it could return this fall when birds fly south for the winter or again next spring.

While this year Midwest turkey and egg farms were hit hardest, the industry that raises chickens for meat in the southern and eastern states including Alabama, Arkansas and Georgia is worried it could spread there.

Still not all poultry producers are on the same page when it comes to using vaccine to fight an outbreak.

Turkey producers tend to favor vaccination to protect flocks because turkey immune systems appear more vulnerable to viruses. Some egg producers and farmers who raise broilers — chickens produced for meat — often resist vaccination programs because of the possible impact on export markets.

U.S. producers export nearly $6 billion worth of poultry and egg products yearly with about $5 billion of that chicken meat.

"There are many unanswered questions that must be addressed before any strong consideration is given to a vaccination program," said Tom Super, a spokesman for the National Chicken Council, which represents producers of 95 percent of the U.S. broilers sold. "Two concerns of several are the effectiveness of the vaccine and potential impacts on trade."

Meetings also have been held with importers of U.S. poultry products to try and convince them not to block all poultry imports if a vaccination program is enacted in response to another outbreak.

"That’s still an open question and we’ve been working with a number of countries today to get them convinced to ban regionally as opposed to the entire country," Vilsack said.

Many countries have a strict policy of refusing to accept meat from nations using a vaccine because it can be difficult to discern through testing whether birds were infected with an active virus or were vaccinated, said James Sumner, president of the USA Poultry & Egg Export Council.

Even during the current outbreak which affected 15 states, about 10 trade partners banned poultry imports from the entire U.S., Sumner said.

Vilsack said it’s uncertain when a vaccine would be ready for large-scale production. Even once stockpiled, a vaccination program would not begin until the USDA, consulting with affected states, decided it was necessary to control an outbreak