All hog farm workers should get a flu shot in October or November in anticipation of this year’s flu season.

“Producers and hog farm workers can reduce the risk of getting sick and bringing the flu to the farm by getting a flu shot,” says Liz Wagstrom, DVM, assistant vice president of Science and Technology for the National Pork Board.

“The flu shot contains two type-A viruses that we want to prevent from spreading between people and pigs,” she points out. “The vaccine also has a type-B virus in the mix, but this type of virus is not of concern to the health of our pigs. Humans will develop antibodies against the flu virus two weeks after taking the flu shot.”

The flu shot is available as an injection or in a nasal spray. “The Centers for Disease Control and Prevention (CDC) recommends that pregnant women not get the nasal vaccine,” she notes.

Wagstrom recommends the following additional practices to reduce infection of pigs with human influenza viruses:

  • Modifying sick leave policies to encourage workers to stay away from the farm if they are suffering. “Virus shedding is at its peak when the clinical illness is most severe, but can last as long as the symptoms do and that is from three to seven days,” she says.
  • Ensuring good building ventilation and good hygiene will also reduce transmission of the flu viruses. “To prevent pigs and humans from other species’ influenza viruses, producers also should look at bird-proofing their buildings, protecting feed from birds and enforcing biosecurity practices, such as the use of farm-specific clothing and footwear,” she says.
  • Chlorinating the water used on the farm is a good idea, especially if it is surface or pond water.

“The CDC has great information about the flu shot, who should get it and who should not. I’d recommend that everybody visit their Web site ( for more information,” adds Wagstrom.

The Pork Board has a fact sheet on influenza: “Influenza: Pigs, People and Public Health,” available at