Bird flu vaccine may be produced for humans

MINNEAPOLIS — Federal officials said Wednesday they were taking steps to create a human vaccine for the bird flu virus that had slammed the Midwest poultry industry, though they still considered the danger to be low and the food supply not at risk.

Dr. Alicia Fry, an influenza expert with the federal Centers for Disease Control and Prevention, said that officials were hopeful there wouldn’t be any human cases of the H5N2 strain — which has cost chicken and turkey producers nearly 6.8 million birds since early March — but that the country must be prepared.

“We’re really at the beginning of this and so are monitoring very closely. And we’re cautiously optimistic that we will not see any human cases,” Fry said on a conference call.

Most humans who have come down with other bird flu viruses had close, prolonged contact with infected birds, Fry said, so officials are monitoring at least 100 farmworkers who’ve been exposed to affected flocks. She said signs could be flulike symptoms or conjunctivitis, also known as pink eye.

It’s standard CDC procedure with all new flu viruses to begin looking at creating a human vaccine, Fry said. She said they were preparing a seed strain, essentially a pure sample of the viruses that could be the foundation for a vaccine.

“We haven’t gotten further than that at this point because we don’t have a need to,” she said.

Similarly, the U.S. Department of Agriculture is testing a seed strain for a potential poultry vaccine but hasn’t decided whether to put it into production, said Dr. David Swayne, director of the USDA’s Southeast Poultry Research Laboratory in Athens, Ga.

Scientists think H5N2 is being spread by wild waterfowl droppings and is making its way past tight bio-security at commercial poultry farms. Although they think it’s probably being carried accidentally on the few people allowed into the barns, USDA Chief Veterinary Officer Dr. John Clifford said officials were also looking at whether high winds could blow tainted dust, feathers and other debris for short distances into facilities.

Because the virus has quickly killed tens of thousands of birds at affected farms across eight states, crews are destroying the rest as a precaution. Clifford estimated that about 3.5 million birds had been euthanized, but that it would take time to cull all of them, particularly at an Iowa farm that had 3.8 million egg-laying hens.

In Minnesota, the country’s top turkey producer and by far the state hit the hardest, health officials are monitoring 61 people involved in caring for affected flocks. Many have followed recommendations that they take the antiviral drug Tamiflu for prevention.

The genetic markers of the H5N2 virus don’t seem to be associated with transmissibility to humans, Fry said. Another good sign is that the H5N2 virus and other viruses in the H5 family that have been circulating in parts of North America appear to be different from H5 viruses that have caused severe human illnesses in Asia, she added.

Still, Fry recommended that the public avoid contact with wild birds and domestic poultry and their droppings.