A Canadian man says a rare disease triggered by the flu shot left him paralyzed for five months, cbcnews.ca reported Wednesday.

Richard Ryan, 44, from New Westminster in British Columbia, said within two weeks of receiving his flu shot last year he was in the hospital with excruciating pain.

Although he initially thought the cause of his pain was a back injury, doctors isolated the problem as Guillain-Barre syndrome, an autoimmune disease that attacks the nervous system.

A 1976 study determined that the odds of developing the syndrome from the flu shot was 1-in-a million, the U.S. Centers for Disease Control and Prevention reports on its Web site. The CDC said most people who develop the disease from the flu shot recover completely, while some have lasting nerve damage. In very rare cases, it may result in death.

In addition to pain, Ryan also suffered from numbness and breathing problems. He spent 10 weeks in the hospital, including three weeks in intensive care, cbcnews.ca reported. One year later he remains heavily medicated, unable to work, and has memory problems.

Despite Ryan's experience, Dr. Danuta Skowronski, an epidemiologist at the British Columbia Center for Disease Control, told cbcnews.ca the benefits of the flu vaccine still outweigh the risks for most people.

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