Genital warts on the decline among Swedish women

Reuters – 22 hrs ago NEW YORK (Reuters Health) - Genital warts have been on the decline among women in Sweden after the country began offering subsidized HPV vaccinations to teenage girls in 2007, new research shows.

Rates of the sexually transmitted infection dropped by 17 percent among women ages 15 to 25 from 2006 to 2010, although there was no change among men over the same period.

The findings are "in all likelihood" a sign the vaccine is working, said Amy Leval of Karolinska Institutet in Stockholm, who worked on the study. But they also suggest that not enough women have been vaccinated for men to be protected indirectly - a phenomenon known as herd immunity - she told Reuters Health by email.

Genital warts are caused by human papillomavirus, or HPV, which in rare cases can also lead to cervical, penile and anal cancers. Health authorities in the U.S. recommend that all preteen girls and boys get an HPV vaccine.

A U.S. expert without ties to the research welcomed the results from Sweden, but also sounded a cautious note.

"It's exactly what we would like to see," said Dr. Michael Brady, an expert in pediatric infectious diseases at Nationwide Children's Hospital in Columbus, Ohio. "But it is a little early to suggest that we know this is a vaccine response."

It's possible that something else, such as better education or an increased media focus, could also have influenced how the disease spread during the study, Brady explained.

"In order to really document this was related to the vaccine, you have to look at those who got the vaccine and those who didn't," he said.

Leval said her work, published in the Journal of Infectious Diseases, is the first to use data from the entire population of a country to estimate the rate of genital wart infections. Such a study would not be possible in the U.S., because there are no nationwide data on the condition.

The Swedish researchers linked two national registries - one on prescription drug use and one on hospital visits - to get estimates of how many people ages 10 to 44 were treated for genital warts.

Their results are likely to be lower than the real rates because the registries don't include people who got non-drug treatments at private practices, such as having their warts frozen off.

Women were most at risk of a new infection around age 20, whereas the rate peaked a few years later in men.

Initially, there was little difference in yearly infection rates between men and women - at 399 and 387 per 100,000 people, respectively. But that began to change after 2007.

While genital warts appeared to become more common among men, the rate dropped off among women, particularly teenagers and young adults.

Leval said HPV vaccinations were recommended for Swedish women up to age 26 during the study, and partially subsidized for girls between 13 and 17.

Twenty-seven percent of girls between 17 and 19 years old were fully vaccinated, she said, and the rate of new infections dropped by a quarter in this age group.

"We see no decline among men yet, indicating no herd immunity effect here when the portion of the population vaccinated is only roughly one-third in the recommended age-groups," Leval said

She added that studies have found signs of herd immunity in men from Australia, where vaccine uptake in girls is about 80 percent.

HPV is the most common sexually transmitted infection in the U.S. According to the Centers for Disease Control and Prevention, at least half of all sexually active people will catch genital HPV at some point, although the virus usually goes away on its own without causing any symptoms.

Researchers estimate that HPV types 16 and 18 are responsible for about 7,000 cases of cancer in men every year in the U.S. and 15,000 cases in women.

Clinical studies show HPV vaccines shield boys and girls against genital warts and cancers, although the protection isn't complete. U.S. health regulators have found no serious side effects apart from soreness at the injection site.

The new results suggest genital warts are the second-most common STI in Sweden after chlamydia, said Leval. This year, the Scandinavian country has replaced its earlier on-demand vaccination strategy with "a school-based and catch-up vaccination program," she added.

SOURCE: http://bit.ly/NU1BPU Journal of Infectious Diseases, online July 18, 2012.

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Health Tip: Help Prevent Warts on the Feet

HealthDay – 4 hrs ago (HealthDay News) -- Plantar warts -- warts that specifically affect the feet -- are caused by viruses and can be quite painful. Children and teens seem to get them more often than adults.

The American Podiatric Medical Association offers this advice for how to prevent warts on the feet:

Unless you're strolling on a sandy beach, don't walk barefoot.Put on a fresh pair of socks each day, and alternate shoes each day.Make sure your feet are always dry and clean.Inspect your child's feet regularly.Do not touch warts on another person or on another part of the body.Pay attention to unusual growths on the skin. Seek prompt medical attention if you find any.

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Genital warts tied to range of cancers

Reuters – 9 hrs ago NEW YORK (Reuters Health) - People who've ever had genital warts may have a somewhat higher risk of several types of cancer -- possibly including common skin cancers, a new study suggests.

The findings, reported in the Journal of Infectious Diseases, confirm some well-established connections between the genital warts virus and certain cancers. And they hint that there could be additional risks.

Genital warts are caused by certain strains of the human papillomavirus (HPV). It's well known that some of those HPV strains -- some of which are the focus of vaccines -- can also promote tumors.

In most people, the immune system is able to clear HPV infection fairly quickly. But some people harbor persistent infections, and a chronic infection with a cancer-linked strain can eventually lead to cancer in some cases.

HPV is probably best known as a cause of cervical cancer -- a disease that experts say is nearly always caused by HPV. The virus is also blamed for most cases of anal cancer, and a large share of vaginal, vulvar and penile cancers.

Lesser known is the link between HPV and certain cancers of the mouth and throat. But a number of studies have found that a large portion of those cancers can be traced to HPV infection.

These latest findings, from a study of more than 49,000 Danish adults, confirm all those connections, said Dr. Susanne Kruger Kjaer of the Danish Cancer Society, who worked on the study.

They also hint that HPV might be involved in the risk of non-melanoma skin cancers -- the most common, and highly curable, types of skin cancer.

CANCER IN LESS THAN FIVE PERCENT

For the study, Kjaer and her colleagues looked at medical records for nearly 33,000 women and 16,000-plus men diagnosed with genital warts over 30 years.

As expected, they had higher-than-average rates of cervical, anal, penile and vaginal cancers, as well as certain mouth and throat cancers.

The vast majority remained cancer-free during the study period. In all, 2,363 people -- or less than 5 percent of the study group -- developed some form of cancer. And only 305 were diagnosed with any of the cancers known to be linked to HPV.

Still, some of those risks were higher than average.

Men with a history of genital warts had a 21 times higher-than-average risk of anal cancer, for instance. Among women, the risk was eight times higher than the norm.

The rates of cervical, penile, vaginal, and mouth and throat cancers were anywhere from 50 percent to eight-times higher, compared with the general population.

There was also some evidence tying genital warts to non-melanoma skin cancers, the researchers say.

Overall, 440 study participants, or less than 1 percent, developed non-melanoma skin cancer -- which is somewhat higher than expected, the researchers say.

It's possible there is some type of connection between HPV and non-melanoma skin cancer, Kjaer told Reuters Health in an email. Since the immune system fights both infections and cancer, it's possible that impaired immune function could underlie persistent HPV infection and skin cancer in some people.

But that's all "speculative" for now, Kjaer stressed.

Non-melanoma skin cancers are the most common type of cancer by far. In the U.S., about 3.5 million cases are diagnosed each year, according to the American Cancer Society.

Experts say the best way to cut your risk of skin cancer is to limit your sun exposure, especially if you have fair skin. No one knows whether preventing HPV infection has any effect.

COULD VACCINES PLAY A ROLE?

For now, there are no "concrete practical implications" from the current findings, Kjaer said.

But if further studies confirm that HPV is associated with a broader range of cancers, that could underscore the importance of preventing the infection, according to Kjaer.

There are two vaccines that can prevent infection with certain cancer-related strains of HPV: Merck's Gardasil and GlaxoSmithKline's Cervarix, both of which cost about $400 for three doses. The current study was funded by Sanofi Pasteur, which sells Gardasil in Europe.

Right now, public health authorities recommend that all girls and boys ages 11 and 12 receive the HPV vaccine. Older girls and young women up to age 26 are advised to get "catch-up" shots if they've never been vaccinated. The same advice goes for boys and men ages 13 to 21.

The HPV vaccine is generally considered safe. The most common side effects are pain at the injection site, fever, dizziness and nausea, according to the U.S. Centers for Disease Control and Prevention.

SOURCE: http://bit.ly/HmRmm2 Journal of Infectious Diseases, online March 15, 2012.

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