Dr. Cate Dewey, professor of swine health management at the University of Guelph, said that a vaccine to prevent “classical” H1N1 influenza infection in swine has existed for years.
“But we don’t have information on how well that vaccine is going to protect pigs from the novel virus,” she said.
The “novel” H1N1 virus is the bug containing pieces of DNA from human, avian, and swine influenza mixed together that health authorities around the world fear may spark a pandemic this fall and winter.
In the few cases where it has passed from humans to pigs, the pigs have suffered only very minor symptoms such as coughing and running nose, with only about 10 per cent of the animals getting infected.
In “classical” swine influenza, the virus spreads rapidly, causing fever and lethargy, and can put entire barns full of pigs off their feed for about four days before they eventually recover, usually within a week.
“So why would we create a brand new vaccine for use in pigs when we already have one? We don’t know if the classical swine flu vaccine is going to protect them from this novel strain because it isn’t the same,” she said.
“We don’t have any evidence that it has gone from pigs to people. We have evidence that it has gone from people to pigs, but not the other way around.”
But the move by the USDA might be aimed at preparing for the possibility that H1N1 could at some future point bounce back and forth between humans and pigs. If that’s the case, it would make more sense to vaccinate hog barn workers instead.
“What pig farmer would pay $2 a pig for a vaccine for a disease that isn’t going to cause much of an illness anyway? But what if the government gave the vaccine free to pig farmers, and said we want you to vaccinate your pigs so that the workers on your farm aren’t getting infected,” said Dewey.
“Then I’d use it. But otherwise, it’s putting an awful lot of money into developing a vaccine that I don’t think there’s going to be a market for.”
Other option would be to put classical and novel H1N1 together in a single combination vaccine. If the price wasn’t too much higher, then it might make economic sense for farmers to use it.
If the Americans are able to develop such a vaccine this fall, then it would likely be approved shortly thereafter for use in Canada, said Dewey. [email protected]