Australia’s current system of universal health care, known as Medicare, was introduced in 1984, two years after the country’s first H.I.V. diagnosis. “When we were then confronted with the greatest public health crisis of our times, we were able to deploy resources,” said Mr. Bowtell, the health policy consultant.
In the United States, he said, the reaction to H.I.V. and AIDS in the early years took on religious and moral overtones — some people described the disease as a punishment from God — and the administration of President Ronald Reagan was slow to act. Australia, by contrast, mostly managed to keep H.I.V. from becoming a moral or a political issue, Mr. Bowtell added.
In 2015, as PrEP was first emerging in Australia, an activist group in Melbourne put up posters with an expletive encouraging people to have sex without condoms. Activists and PrEP users say they accurately captured the sense of freedom that Truvada has granted.
People living with H.I.V. have long carried the burden of preventing its spread, said Mark Binette, 34, a physiotherapist from Melbourne who is on PrEP. The regimen, he added, offered a way to help shift that responsibility.
PrEP is not the only reason for declines in H.I.V. transmission: In many cases, antiretroviral drugs reduce the presence of the virus in patients’ bodies to levels so low that they will not pass it on to others. But to ever fully eliminate H.I.V. transmission, a vaccine will most likely be needed, scientists say.
Also crucial is ending the stigma attached to the virus, which can stop people from seeking access to prevention measures and treatment, said Dr. Edwina Wright, a physician and clinical researcher at the Alfred Hospital at Monash University in Melbourne.
“It’s not all biomedical,” Dr. Wright said. “If we could have a vaccine in the short term against stigma,” she added, “that would be great.”