Nam isn't sure how he caught the HIV virus -- he says he is a former heroin addict and often had unprotected sex -- but now he is committed to helping other Vietnamese youths avoid the same fate.
Aged 28, he works for a project to educate young people, the most at-risk group from HIV and AIDS, and to change public attitudes toward those infected, who he says are still too often shunned and punished by society.
Nam and other members of an HIV youth advisory panel Wednesday met Haruhiko Kuroda, president of project-funder the Asian Development Bank (ADB), at a Hanoi youth centre dubbed "the condom cafe."
The 20-million-dollar ADB project -- which will include a 105-episode television drama series with HIV themes set to launch in June -- aims to spread information about the disease in Vietnam through stories such as Nam's.
"My family is quite wealthy," he told AFP. "When I was 14 or 15, I was curious about heroin, about having that strange feeling. I tried it once, then again, then a third time. After a while I was addicted."
At first he smoked the drug but later he changed to syringes for a more intense high, said Nam, who preferred to be identified only by his first name.
"To smoke heroin, you need to find a private, quiet place, out of the wind," he said. "But you can inject heroin quickly, even in a streetside tea shop."
During his teenage years, Nam said, he had a number of girlfriends and always had unprotected sex, remembering that "it was strange to use condoms."
After 10 years he kicked the heroin habit, which he called "the hardest thing to do. If you haven't been addicted, you can never understand," he said.
"I realised I had the HIV virus five years ago," Nam said. "I tested positive after I arrived in China for university studies. I don't know when I got infected. I was shocked, I absolutely collapsed, I felt numb."
Today, Nam says he is on anti-retroviral drugs and in good health. His colleagues at the Vietnam Youth Union centre praise his courage and dedication in his new role, which includes webpage design for HIV education.
Nam is one of almost 300,000 Vietnamese believed to be living with HIV.
Intravenous drug users, prostitutes and homosexual men still make up the largest number of infected people here, but health experts warn that the virus is now spreading fast into the wider population of 86 million.
More than half of those hit are in their 20s, which is why the ADB-funded project aims to raise the participation of young people in advocacy and efforts to fight HIV in the communist-run country.
"Through this project we get our voices heard and we can advise the leaders on what needs to change," said Vu Tuan Anh, a member of the HIV advisory panel.
Another youth, Nguyen Trung Kien, added: "In some places we have tried to distribute free condoms and clean needles, especially to the high-risk groups.
"People and leaders used to think that this was a way to encourage young people to do bad things rather than curbing HIV/AIDS."
In their meeting with Kuroda, the youths also talked about information websites and music concerts that highlight the HIV threat, performed a small play, and spoke of upcoming radio and television shows.
The television drama series is due to start airing in June, said Ken Swann of the BBC World Service Trust, which is helping produce the multi-media campaign.
"It's about a neighbourhood and deals with love and romance and everything about teenage life, including risks they face such as HIV," he said.
Kuroda said he hoped the youth project could be replicated elsewhere.
"HIV/AIDS is a very grave and difficult disease," he said. "It affects the infected person and also their family very seriously, so the best way is to prevent HIV/AIDS among people, particularly young people."