The number of New Zealand gay and bisexual men with diagnosed
HIV more than doubled between 1999 and 2009, University of
Otago research shows.
The study by Otago University researchers based in Dunedin
and Auckland found an estimated 1313 gay and bisexual men
were aware they had HIV in 2009 - which was an increase of
137% from 1999. This compares to an increase of 79% between
1989 and 1999.
Overall, 1936 gay and bisexual men were identified with HIV
over the past 25 years, with 720 diagnoses and 552 deaths.
The study's lead author Dr Peter Saxton, of Otago
University's Department of Preventive and Social Medicine's
Aids epidemiology group, said the more rapid rate increase in
the decade up to 2009 was largely due to the introduction of
"very effective" antiretroviral therapies from 1997, which
improved the life expectancy of people with HIV.
This meant fewer people who had HIV were dying and this
combined with new infections every year meant the number of
people with HIV was increasing at a greater rate, Dr Saxton
There had also been an "escalation" in the number of
infections among gay men since 2003, due in part to the
growth of online dating sites, which made it easier for
people to find sexual partners.
"That includes sites like NZ Dating and ... also smartphone
apps like Grinder, which are unique to gay men," he said.
This increased the likelihood of gay men contracting HIV and
inadvertently transmitting it to a greater number of people
before they knew they had it.
The other reason was that anal sex was a much more "efficient
mechanism" for transmitting HIV than other types of sex.
"I think those two are the main explanations why we are
seeing quite a different trajectory of the HIV epidemic
amongst gay men, not just in New Zealand, but
internationally," he said.
There were some encouraging signs that infection rates were
decreasing. The number of new transmissions dropped in 2011
and condom use among gay men was not decreasing, Dr Saxton
The research was published in the International Journal of
STD and Aids earlier this year.