"The human papillomavirus is the most common sexually transmitted infection," Heath Minister Terry Lake said in a statement. "It can lead to serious health problems and could develop into an HPV-related cancer."
The government defines "vulnerable" at-risk boys and young men as "those who have sex with males or who are street-involved."
A government statement said the vaccine won't be extended to all boys because "providing the vaccine for all girls [more than 50 per cent of them are vaccinated] protects heterosexual boys ... but leaves at-risk boys and young men unprotected."
B.C. is the fourth province to announce it will provide the vaccine to boys.
It's clear some men are more at risk for HPV-related cancers than others, said Perry Kendall, B.C.'s provincial health officer.
"As most of these infections are vaccine-preventable, extending B.C.'s HPV immunization program to this at-risk demographic is a cost-effective way to provide protection to the people who need it most," he said.
The government will supply the Gardasil vaccine for the program, saying it protects against HPV infections that cause about 70 per cent of cervical cancers, 80 per cent of anal cancers and other cancers of the mouth, throat, penis, vagina and vulva.
The vaccines will be administered at specialized clinics and programs for street-involved youth as well as public health units, the government said.