Toronto Public Health is expanding its Human Papillomavirus vaccine program to give teenage girls who missed their HPV vaccinations in Grade 8 a chance to get the shots for free at clinics throughout the city.

The vaccination protects against certain strains of HPV, which is the primary cause of genital warts and the agent behind about 70 per cent of cervical cancers.

The expansion to the vaccine program began at a temporary clinic at the Scarborough Civic Centre in the city's east end on Monday, where girls aged 13 to 19 could receive inoculations.

Vinita Dubey, Toronto Public Health's associate medical officer of health, says the city has already sent out 19,000 letters to girls due for vaccinations, while an additional 16,000 letters still need to be mailed out.

The outreach effort developed in June when the Ontario government announced more funding in response to health organizations advocating free vaccination for girls who missed their shots in Grade 8 after the program's 2007 launch.

Dubey says the vaccine — composed of three shots and recommended especially for women 26 years or younger — will cost $450 for boys and anyone 20 or older.

But she hopes that as word gets out, the vaccine will reach as many girls as possible through community clinics this fall and in January.