In what one researcher said was "jarring," 54% of HIV-negative young adults didn't report using condoms or PrEP — two critical tools in preventing the spread of the virus that causes AIDS — according to the results of a survey released by pharmaceutical company Merck November 25.

The national survey, "Owning HIV: Young Adults and the Fight Ahead," was conducted over the summer in conjunction with the Prevention Access Campaign, a group seeking to promote the knowledge that HIV-positive people with undetectable viral loads cannot transmit the virus as part of the U=U (undetectable=untransmittable) campaign.

The survey of 1,596 people had questions about HIV of adults from both the millennial generation, defined as ages 23-36, and Generation Z, defined as ages 18-22 for purposes of the study.

"This was a groundbreaking, first-of-its-kind survey with this demographic," said Dr. Peter Sklar, a straight ally who is director of clinical research at Merck Research Laboratories. "The results were really jarring to all of us."

For decades, condoms were the only known way to prevent transmission of the HIV virus between HIV-positive and -negative individuals, when used and functioning properly. Once-daily Truvada, approved by the U.S. Food and Drug Administration in 2012, has been shown to reduce the risk of acquiring HIV by more than 90% among gay and bisexual men when taken as prescribed. Studies have also shown a high level of protection for women, heterosexuals, and people who inject drugs. Read more via ebar