HIV-related internet searches hit a record level after American actor Charlie Sheen confirmed publicly that he has the virus, say researchers who hope the online impact translates into prevention.

Sheen appeared on the Today show last November with his doctor to also talk about how his HIV load was considered undetectable — meaning the amount of virus particles in his blood is below the level that can be picked up by lab tests.

The former star of television comedies Two and a Half Men and Anger Management also claimed he disclosed his status to all his sexual partners, although that has been disputed.

Researchers in the U.S. have analyzed trend data from global English-language news reports dating back to 2004, as well as internet searches for HIV, condoms, and HIV symptoms and tests, to determine if Sheen's disclosure renewed attention to the virus.

'While no one should be forced to reveal HIV status, Sheen's disclosure may benefit public health by helping many people learn more about HIV infection and prevention.'
- Study authors

In general, news reports about HIV decreased from 67 stories per 1,000 when the study began to 12 stories per 1,000 in 2015.

But the day of Sheen's disclosure coincided with a 265 per cent increase in news reports mentioning HIV. That made it among the top one per cent of HIV-related media days in the past seven years, John Ayers of San Diego State University and his co-authors say in a letter published in Monday's issue of JAMA Internal Medicine.

"Sheen's disclosure also corresponded with the greatest number of HIV-related Google searches ever recorded in the United States," they wrote.

What's more, of the 2.75 million more searches than expected to include HIV at that time, 1.25 million were relevant in public health terms because they included search terms such as condoms, HIV symptoms or HIV testing.

"Just as with celebrities Rock Hudson's and Magic Johnson's disclosures of their HIV-positive status, Sheen's disclosure may be similarly reinvigorating awareness and prevention of HIV," the authors said about the late actor Hudson, and Johnson, the former basketball star who has been living with HIV for more than 25 years.

"While no one should be forced to reveal HIV status, Sheen's disclosure may benefit public health by helping many people learn more about HIV infection and prevention. More must be done to make this benefit larger and lasting."

For example, Ayers said he's unaware of any major HIV educational campaigns that are using Sheen's disclosure for public health outreach.

"Sheen is a controversial figure and it's incredibly hard to frame public health messages around a figure whose behaviour, not unlike any non-celebrity or myself, may at times conflict with public health science," Ayers said in a release.

Dr. Mitchell Katz, a deputy editor at the journal, wrote an editor's note published with the letter that's titled "Adapting health education for the internet age."

Doctors have long seized teachable moments such as an episode of bronchitis to address quitting smoking. Katz said to apply that to public health for HIV, individuals need to know where to go to obtain the services they need, in a language they speak in the community where they live.

"We can provide more effective messages about public health if we adapt traditional methods of health education to our increasingly social media–driven world and make sure the messages are available in advance of the next celebrity disclosure," he suggested.