Four years after approving Gardasil for use in young women, Health Canada has approved the HPV vaccine for use in boys and young men from nine to 26 years old, announced manufacturer Merck on Tuesday. 

Merck's research has shown that Gardasil helps prevent HPV-related genital warts and anal cancers among gay men.

Health Canada says three in four sexually active Canadians will have at least one HPV infection in their lifetime. Only a small proportion will go on to develop cancer, but the US Centers for Disease Control says gay men are 17 times more likely to develop anal cancer than straight men.

Canadian provinces have school-based vaccination programs for young girls, but it's not immediately clear if and when the vaccine will be given to school-aged boys. 

A Health Canada spokesperson confirmed the Gardasil announcement with Xtra: "On February 22, 2010, Health Canada granted authorization to Merck Frosst that will allow it to market Gardasil for boys and men 9 through 26 years of age in Canada."

Read more:

• HPV vaccine effective in men, suggests new research
• Nobel laureate calls for HPV vaccine for boys 
  
• The promise of Gardasil: How medical science has left gay men in the lurch