Gay teenagers who have had at least four
sexual partners are at increased risk of contracting human papillomavirus
(HPV), a new study suggests.
At least half of sexually active people get
HPV at some point in their lives, according to the Centres for Disease Control
and Prevention (CDC).Previous research has suggested most adult gay men have
the sexually transmitted infection.
HPV is usually cleared by the immune system
but can cause genital warts and anal cancer, as well as cervical cancer among
women. "In this study we found rates of anal infection increased rapidly with
increasing numbers of partners with whom they have had anal sex,"
senior author Marcus Y Chen said. "The virus is presumably being
transmitted from penis to anus. "Chen is an associate professor in the
School of Population and Global Health at the University of Melbourne in
The CDC recommends boys and girls get
vaccinated against HPV at age 11 or 12, before becoming sexually active. There
are two versions of the HPV vaccine, one of which is available for boys.
the vaccine effective?
The vaccine is very effective if given
before a person is exposed to HPV but provides "diminishing
protection" after that, Dr Ross D Cranston told Reuters Health. "Thus
if there is a high rate of HPV acquisition, as we also see in girls, there is a
lost opportunity to provide protection if the HPV vaccine is not given
early," he said.
Cranston, who was not involved in the new
study, directs the Anal Dysplasia Clinic and Research Program at the University
of Pittsburgh Medical Centre in Pennsylvania.
Sexual history questionnaire
Chen and his team tested 200 young gay men
age 16 to 20 for HPV and genital warts and gave them a sexual history
One-third of the men tested positive for
high-risk forms of the virus, and 11% tested positive for two or more forms.
Men who'd ever had vaginal sex or anal sex were more likely to test positive for penile HPV, according to results published in the Journal of Infectious Diseases. Among men who had never received anal sex,
10% tested positive for anal HPV. That compared to nearly half of those who
said they'd had at least four anal sex partners.
The finding that some young men who
reported never receiving anal sex tested positive for anal HPV suggests the
virus can be transmitted in other ways, the authors write.
About 7000 people in the US will be
diagnosed with anal cancer in 2013, according to the American Cancer Society.
Rates are higher among gay men than heterosexual people, Chen noted.
Of the many types of the HPV virus, HPV 16
is most commonly associated with anal cancers."Our study found that gay
male teens acquire the HPV virus including HPV 16 very soon after they first
become sexually active," Chen told Reuters Health.
"This means that the HPV vaccine,
which has been shown to be effective in preventing HPV infection in males,
including anal infection in gay men, needs to be given very early on,
preferably before gay teens start to have sex. "Many countries routinely
vaccinate all girls against HPV.
Universal and free vaccination
But as of 2013, Australia is the only one
to implement universal and free vaccination of boys at school, Chen
said. "This is great news for boys in Australia including those that are
gay but in other countries the absence of such a programme means gay males will
miss out on anal cancer prevention," he said.
Some gay teens might be reluctant to admit
their sexuality and ask for the vaccine, he said.
Gay men are no more susceptible to HPV than
heterosexual men, but more often have anal infections, Cranston said.
He said doctors can increase awareness and
the likelihood that boys will be vaccinated against HPV through conversations
with their parents.