Sexual health advocates say a new HIV prevention drug to be covered for eligible Albertans should help lower transmission rates of the disease.

Starting Oct. 1, the cost of pre-exposure prophylaxis, or PrEP — a daily pill that is up to 99 per cent effective in stopping the transmission of HIV — will be covered for eligible Albertans.

The government will also expand the number of physicians who can prescribe the medication, said Premier Rachel Notley, in an announcement Saturday. The generic form of the drug is $250 per month — about $8.30 a day. The brand name, Truvada, can cost up to $1,000 per month.

The high costs have made the drug difficult to access for some vulnerable and at-risk Albertans, said Laura Keegan, director of public engagement for HIV Edmonton.

"This is a real game changer," Keegan said. "It's the right public health decision to have PrEP made available. Paying for prevention is less than paying for treatment.