One of the HPV vaccines available in Canada has now been approved for use by boys and men.
Merck announced Tuesday that Health Canada has approved its vaccine Gardasil for use in boys and men aged nine through 26.
The vaccine is designed to prevent infection from the HPV strains that can cause genital warts (types 6 and 11). It can also protect against HPV types 16 and 18 which, when sexually transmitted to women, can cause cervical cancer.
Human papillomavirus, which has more than 100 strains, is the most common sexually transmitted infection in Canada.
According to a Canadian study recently published in Sexually Transmitted Diseases, 56 per cent of young people in a new sexual relationship were found to be infected by HPV. Those infected were, on average, infected with 2.8 strains of the virus.
Gardasil was approved by Health Canada back in 2006 for women and girls aged nine to 26 to prevent cervical cancer and genital warts. Every province and territory now offers school-based HPV vaccination although the age group targeted varies by jurisdiction, from Grade 4 in Quebec through to Grade 8 in Ontario.
Currently, all school-based programs use Gardasil. But two weeks ago, Health Canada approved a new HPV vaccine, GlaxoSmithKline's Cervarix. Cervarix offers protection against HPV 16 and HPV 18.
Genital warts a common STI
An estimated 40,000 new cases of genital warts are diagnosed each year in Canadian men and women. Merck says that 90 per cent of cases are caused by the HPV strains covered by the Gardasil vaccine, types 6 and 11.
Dr. François Coutlée, a clinical researcher at the Molecular Virology Laboratory, CHUM - Hôpital Notre-Dame, who has been researching the use of Gardasil in men, says most people who get genital warts will eventually be able to fight off the infection.
"For most individuals who develop genital warts, it's just a matter of time when their bodies will fight it off. It can take six months, two years, three years," he told CTV.ca. "But for 95 per cent of individuals, the immune system will fight off the infection."
In the meantime, he noted, most will develop the unsightly and embarassing warts that can be uncomfortable to remove.
"Warts don't kill but you have to go for treatment and retreatment for recurrences. So there is a psychological and physical burden of getting infected with genital warts," Coutlée said.
He also noted that even those who have successfully fought off infection with one strain of HPV can still be infected again.
"Infection with multiple types at the same time is a possibility," he said. "Even if you've been infected with one type doesn't mean you can't be infected by another type. And there are about 40 genital types around. So lots of genital types."
Coutlée is now taking part in research to test Gardasil's ability to prevent anal cancers in men. In a recently-completed Phase 3 study, the vaccine prevented 77.5 per cent of the pre-cancerous lesions that can lead to anal cancer in 16-to-26 year-old gay men.
