In the heart of the 1980s AIDS epidemic, a pill to prevent HIV would have been nothing less than a revolution.

Less than 40 years later, that pill is here, and in February it was approved by Health Canada. So why aren't those who want it able to get it?

The drug Truvada has been used to treat HIV for over a decade, but recent clinical trials show, if taken daily, it can also reduce the risk of getting HIV by more than 90 per cent. In this case, Truvada is used as pre-exposure prophylaxis — also known as PrEP.

It works by spreading enough antiretrovirals in the body that if exposure occurs, it stops the virus from entering cells and replicating.

PrEP has proven especially beneficial for those at high risk of acquiring the virus, including men who have sex with men, sex workers and those with an HIV-positive partner.

Matt Numer, Dal University

Matt Numer, a professor at Dalhousie University, has been taking PrEP since before it was approved in Canada. (CBC)

Matt Numer, a professor at Dalhousie University in Halifax, has been using PrEP since before it was approved in Canada. He says it's reduced some of the anxiety he felt around HIV.

"I'm on [PrEP] largely for peace of mind. If anybody's gone through the process of HIV testing, even when it's a regular part of your life, it's a stressful thing for people to do, and [PrEP] really alleviates that stress."

Numer says he's delighted to be on it, but that he's one of the "lucky ones". Most who want the drug can't get it.

What is PrEP?

If you've never heard of PrEP, you're in good company.

One of the barriers for those who want to use PrEP is that relatively few people — including doctors — know much about it. That's partly due to how new it is.

Dr. Tim Matheson, a family physician in Nova Scotia who has hundreds of gay patients, recently prescribed PrEP to two patients at risk of getting HIV. But most physicians don't yet feel comfortable doing that.

Dr. Tim Matheson

Dr. Tim Matheson is a family physician in Nova Scotia who recently prescribed PrEP to two patients at risk of getting HIV. (CBC)

"My understanding in talking with other doctors is that they're not all that aware of the protocols for managing it, and what the general consensus is on how we should approach PrEP here in Nova Scotia," he says.

Prescribing PrEP isn't as simple as prescribing, for example, a year's worth of blood pressure medication. Patients on PrEP must be tested for HIV before being put on the drug, and must return every three months for blood tests and to check bone density and kidney function to see how their body's responding to the drug.

Side effects of PrEP are relatively minimal, but could include nausea, abdominal cramping, vomiting, dizziness, headache and fatigue.

PrEP coverage in Canada

In the U.S., PrEP has been approved since 2012 and the country's leading public health institute, the Centers for Disease Control and Prevention, has put out guidelines and brochures like: "Are you ready for PrEP?" and "How to talk to your doctor about PrEP."

Here in Canada, the Public Health Agency of Canada says it supports the use of PrEP but appears hesitant to start a conversation about it.

In response to CBC's request for information, it said in an email,  "[PrEP] is a new tool that can contribute to HIV prevention, along with other prevention methods." But it also confirmed it's not currently planning to release guidelines or educational material about the drug.

Truvada

PrEP was approved for use in Canada in 2016. (CBC)

In Quebec, where PrEP is covered by the provincial drug plan, the Ministry of Health has been giving advice for the past couple of years, according to Ken Monteith, executive director of COCQ-SIDA.

"Clinicians and researchers and the community pushed for the ministry to produce advice, which should become, at some point in the next year, actual official guidelines."

Canadian HIV Trials Network, a group supported by the Canadian Institutes of Health Research, is also working on guidelines for clinicians on the use of PrEP. Those are expected later this year.

Stigma of PrEP

San Patten, an HIV research consultant, says the stigma attached to HIV has likely transferred to PrEP, so there's also moral judgment around its use. This could be the reason some are hesitant to talk about it, she says.

People may believe that taking PrEP will increase risky or promiscuous sexual behaviour, she says. Patten likens that thinking to the initial reaction to the birth control pill. There's also fear that those using PrEP may use condoms less, and thus be at higher risk of getting STIs.

San Patten, HIV research consultant

San Patten, an HIV research consultant, says people may believe prescribing PrEP will increase risky sexual behavour. (CBC)

Although doctors still recommend using condoms while on PrEP, Patten says the evidence suggests most people don't achieve 100 per cent condom adherence as it is, and that's not likely to change.

About 2,000 new HIV infections are diagnosed every year in Canada.

"In our statistics, our prevalence and our incidence rates over the years, we're not making a huge dent through condom promotion messages. So we need another tool," she says.

Because PrEP users get tested every three months, STIs would be caught and treated quickly, perhaps even more so than if they weren't taking PrEP, she says.

Accessing PrEP

Earlier this year, Davey Dow thought he may have contracted HIV. Although he tested negative, the anxiety he felt waiting for that result prompted his interest in PrEP.

"As a gay man that's always been a fear of mine," he says.

Knowing he wouldn't have to worry about what he calls "the big one" would give him peace of mind. But Dow now feels discouraged about the prospect of taking PrEP— in part because he's yet to find a doctor comfortable prescribing it.  He says the last health professional he saw didn't recommend it.

Davey Dow

Davey Dow says he has yet to find a doctor who is comfortable prescribing PrEP. (CBC)

He also doesn't think he'll ever be able to afford it — and with a price tag of just under $1,000 a month, he's not alone.

Some private insurance plans cover it, others don't. Most are still trying to figure out what to do with it. Certain states in the U.S. cover the cost of PrEP entirely; here in Canada, the only province to do so is Quebec.

It's unclear if other provinces will follow suit.

Future of PrEP in Canada

Nova Scotia's public health department told CBC News in an email, "Like other jurisdictions, we are waiting for the Common Drug Review to complete its process and we look forward to reviewing that recommendation when it arrives."

Final recommendations from that review — by the Canadian Agency for Drugs and Technologies in Health — are expected this fall. That could have an impact on whether provincial governments will cover the drug, as well as public health strategies around it.

For now, those like Dow will have to wait and see how it all plays out.

Numer says he hopes policymakers will move past moral judgments and look at the evidence.

"If we had a similar pill for, say heart disease, or other diseases that have a behavioural component, there would be no question, people would be lined up around the corners," he says.

"I think that we would be well advised and well rewarded in terms of how we treat people in the health care system if we were to provide access to this."