There’s a pill that, when taken once a day, can prevent HIV infection. It's called pre-exposure prophylaxis (PrEP) and at the moment it's prohibitively expensive. In 2016, for example, one year’s supply could cost as much as $10,000. 

That’s about to change.

From 1 April 2018, PrEP will be subsidised by the Australian Government through the Pharmaceutical Benefits Scheme (PBS), Health Minister Greg Hunt has announced.

That means eligible people will pay a maximum of $39.50 per script, while concessional patients will pay just $6.40.

Pre-exposure prophylaxis can protect HIV-negative people from getting HIV. When taken correctly, it's 99% effective at preventing HIV transmission among gay and bisexual men. This means is still possible to contract HIV while taking PrEP, but it's unlikely.

The drug may be prescribed for people who are at high risk of getting HIV, such as:

• a man who has anal sex with other men and does not always use a condom
• a woman, with a heterosexual partner who has HIV, who wants to get pregnant
• a person with a partner who is HIV-positive but has not achieved an undetectable viral load (UVL), and who does not always use a condom. (UVL occurs when an HIV-positive person takes enough treatment to reduce the level of HIV in their body – known as ‘viral load’ – so it becomes undetectable.) 

“Gay and bisexual men continue to carry the greatest burden of HIV in Australia, and we expect that PrEP will sharply drive down rates of HIV for this community,” says Darryl O’Donnell, chief executive of the Australian Federation of AIDS Organisations.

"Additionally, Aboriginal and Torres Strait Islander people, migrant communities and some heterosexual populations have seen starkly higher rates of HIV transmission over the past 5 years… we must make sure everyone who needs PrEP is aware of it and can access it."

Adding PrEP to the PBS will benefit the whole community financially, explains Mr O'Donnell, saving taxpayers millions of dollars in "lifetime costs" by preventing new cases of HIV.

PrEP won't guard against other sexually transmitted infections (STIs) such as hepatitis B, syphilis or gonorrhoea, so it’s important to also use condoms while taking the drug. PrEP isn’t without side effects, either: when starting the medication, it’s common to experience symptoms such as nausea, dizziness, headaches, fatigue and stomach cramps. Some people may experience few to no side effects, while for others the symptoms usually go away within a few weeks. 

You should talk to your doctor or GP about whether PrEP is right for you, and they will be able to prescribe it through the PBS from April 1 to eligible Australian residents with a Medicare card.

If you think you may be at high risk of exposure to HIV, visit your doctor or the Australian Federation of AIDS Organisations site for more information.