Men may still face the risk of developing HPV-related cancers, the study authors found, according to HealthDay.
However, males still have a risk of developing HPV-related cancers, the study authors said.
The researchers also found that although vaccinating boys would reduce the burden of later HPV infection in men, it might not be a cost-effective move because hundreds of boys would need vaccinations to prevent prevent one case of cancer caused by HPV.
Countries around the world are trying to figure out how widely the vaccine should be distributed, and the studies help shed light on this. HPV causes cervical cancer in women and the vaccine was developed to prevent this.
If there’s one thing the study does show, it’s that “it’s a complicated situation,” said Karen Canfell, director of cancer research with Cancer Council NSW in Sydney, Australia, HealthDay reports. She wrote a commentary accompanying the study, and noted “even though we have evidence that the vaccine is effective in boys, there are a number of other issues that need to be considered.”
In the U.S., about 79 million people are currently infected with HPV, the U.S. Centers for Disease Control and Prevention (CDC) notes. In fact, HPV infections are so common that almost everyone who’s sexually active will have the virus at some point.
What is HPV?
Human papilloma virus is actually a group of more than 150 related viruses. Named for the warts, or papillomas, that some HPV types cause, each virus in this huge group is given a number which is called its HPV type, the CDC reports. Other HPV types can lead to cancer, especially cervical cancer. More than 40 HPV types can infect our genital areas. Fortunately, there are vaccines that can prevent infection with the types of HPV that are most common.
How HPV is transmitted:
It’s transmitted through intimate skin-to-skin contact, the CDC reports. You can contract HPV via vaginal, anal, or oral sex with someone who has the virus, and it’s most commonly spread during vaginal or anal sex. It’s also the most common sexually transmitted infection (STI). Anyone who’s sexually active can become infected, and that’s even if you’ve had sex with only one person. Plus, it can be passed even when an infected person shows no signs or symptoms. It can also take many years for symptoms to show up after you’ve had sex with an infected person, and this makes it difficult to know when you first became infected.
Gardasil, also known as Silgard in Europe, is the vaccine used to protect against HPV, and a new version of the vaccine has recently been approved by the U.S. Food and Drug Administration, The Skeptical Raptor reports. Gardasil protects teens and young adults from nine subtypes of HPV, and this means it helps prevent more cancers.
One interesting aspect of the study: The researchers found that there was a benefit for men brought about by reducing HPV circulation among women via the Gardasil vaccine. They also realized there was an additional benefit from vaccinating boys against HPV. With higher vaccine coverage among girls, the additional benefit against HPV-caused cancers — anal, penile, and some throat cancers — would come from preventing the infection in men who engage in sex with other men, the Skeptical Raptor reports here.
The scientists designed the study to estimate the cancer fighting benefits to men if boys and girls were both vaccinated in their country. In the Netherlands, only girls are universally vaccinated. The U.S., Australia, Austria, and two provinces in Canada are among the only places that have a policy of HPV immunization of boys.
According to the researchers:
“Men will benefit indirectly from vaccination of girls but remain at risk of cancers associated with HPV. The incremental benefit of vaccinating boys when vaccine uptake among girls is high is driven by the prevention of anal carcinomas, which underscores the relevance of HPV prevention efforts for men who have sex with men.”
The study, published online on May 12 in The BMJ, the researchers used statistical analysis to predict what would happen in regards to cancer levels in men if more and more boys and girls were vaccinated, HealthDay reports.
“Of all HPV-associated cancers, vaccinations of girls will have the strongest effect on the occurrence of penile cancer and the smallest effect on the occurrence of anal cancer in men,” said Hans Bogaards, the study’s lead author and a research scientist with the National Institute for Public Health and the Environment in the Netherlands.
Why will this have a lesser impact on anal cancer? Well, some of these cancers may be due to HPV infections acquired when men have sex with other men, the study authors say.
The researchers estimate that HPV-related cancer in men, in a measure that takes into account quality and quantity of life, would shrink by two-thirds if 90 percent of girls received vaccinations. If the vaccine rates stay at the rate of 60 percent — where they are now — HPV-related cancer in men would drop by 37 percent, the study reports.
As more girls receive the vaccine and HPV-related cancer rates drop in men, more boys will need vaccinations to prevent one cancer in men, the author say. So this means preventing each cancer will become costlier.
Currently the vaccination levels are at 60 percent for girls, and nearly 800 boys will need to receive vaccinations to prevent one additional HPV-related cancer in men, the study reported. If vaccination rates for girls jumped to 90 percent, over 1,700 boys would need to be vaccinated in order to prevent one HPV-related cancer in the men, the study estimated.
Girls should still be the top priority for HPV vaccination, Canfell said, “since cervical cancer comprises the largest burden of the HPV-related cancers, and because males will also benefit, to some extent, from female vaccination.” Developed countries that have already introduced successful vaccination programs for girls may want to consider vaccinating boys, she said.
Another possibility would be to target bisexual and gay men who visit sexually transmitted-infection clinics, Canfell said, because they are especially vulnerable to HPV infection. Vaccination of girls won’t provide much protection.
“The United Kingdom is considering vaccination of this group up to the age of 40 years,” she said. “This option can be evaluated alongside considering universal vaccination of young boys. Both strategies could be potentially implemented at once.”
Bogaards also thinks that vaccination of gay and bisexual men shows promise as a cancer prevention tool, and he supports more research into its potential effects, HealthDay reports.
There are currently three HPV vaccines available in the United States: Cervarix, Gardasil, and Gardasil 9. These vaccines should be administered as a series of three shots over six months, according to the CDC. It’s recommended that girls between ages 11 or 12 get the HPV vaccine to help prevent cervical cancer. Gardasil and Gardasil 9 also help to prevent genital warts and anal cancer in both men and women, the CDC reports.
