Watching Women's Health

HPV vaccine effective in some older women

The HPV vaccine, Gardasil, is FDA-approved for use in females ages 9-26. Some of my patients who are older than 26 would like to get the vaccine, and they wonder why it is not approved for their age group.

Now, a new study from the National Institute of Cancer in Bogota, Columbia suggests that the vaccine may be effective for some women up to age 45.

Approximately 1600 women ages 24-45 received all three doses of the vaccine and were compared to a similar group of women who got placebo shots. Women in both groups had no history of genital warts or cervical disease. They also tested negative for the HPV types 6,11,16 and 18 covered by the vaccine.

After 2 years of followup, more than 90% of vaccinated women tested negative for the HPV vaccine  subtypes. Only 4 of 1615 vaccinated women had evidence of persistent HPV infection by any of the four subtypes. 41 of 1607 women in the placebo group had persistent HPV infection. 

The study also looked at a mixed population of women in the same age group, some of whom had previous or current HPV infection. In that group, the vaccine effectiveness was less than 30%.

The HPV vaccine has the greatest medical and cost-effectiveness when given to adolescents and young women who have not yet become sexually active. With no prior HPV exposure, this group gets the full benefit of the vaccine's protection against cervical cancer and genital warts. Teens also have a more robust immune response to the vaccine than older women.

However, some women in their later twenties and older have had minimal or no exposure to HPV and could benefit from vaccination. If other studies confirm that HPV vaccination is beneficial for a broader age group, the FDA may extend approval to those women.

For now, when we vaccinate women 27 and above for HPV, it is an off label (not FDA-approved), but still acceptable, use of Gardasil.  Even though the FDA has not yet approved the vaccine for these women, physicians can use their judgment and offer the vaccine to informed, older women who request it.

Vaccinating males for HPV

It has been almost three years since the FDA approved the HPV vaccine for use in girls and women age 9 to 26. Some of my patients have asked why we don't vaccinate males for HPV. Don't men get HPV too? And isn't that who most women get it from?

Good questions. Men do get HPV and pass it to women. But the consequences of HPV infection are different for the two genders.

Females have an area on the cervix, the transformation zone, that is especially vulnerable to effects of HPV. Persistent HPV infection puts women at particular risk for cervical cancer, in addition to cancers of the vagina, vulva and perianal area.

HPV infection causes cancers in men too, but less commonly and with less deadly results. In the US, about a 1,000 men per year die from HPV-related cancers, involving the penis, anal area, mouth and throat.

More than four times as many women die of cervical, vaginal and vulvar cancers. And, treatment of cervical precancers increases the risk of preterm delivery in subsequent pregnancies. So it was reasonable to vaccinate girls and women first.

Recently, Merck & Co, manufacturer of the HPV vaccine, asked the FDA to approve it for use in males too. Today, The Washington Post reports on how the debate about vaccinating males has been different from the debate three years ago about vaccinating females.

Much of the earlier discussion centered on the question of whether the HPV vaccine would encourage girls to become sexually active at an earlier age. Most of the discussion about male vaccination has focused on safety and cost-effectiveness. 

Gregory Zimet, a professor of pediatrics at Indiana University quoted in the article, says "The cost-effectiveness studies are really important, but I don't think they should be the sole driver of public health policy."

Zimet also says, "This is a vaccine that principally benefits women's health. I wonder if it was the reverse, and there was a vaccine for women that helped prevent prostate cancer in men, this would be as much of an issue." He notes part of the case for men to be vaccinated is an "altruistic argument," which makes it more complex. Some of Zimet's research on HPV has been funded by Merck.

A recent article from the American Board of Family Medicine looked at adult male attitudes toward HPV vaccination. Men were most likely to accept the HPV vaccine if they were well-educated, knowledgeable about HPV and had personal behaviors that put them at higher risk for HPV infection.

The factor least likely to make them want to be vaccinated was a request by a partner. Right now, it doesn't seem like altruisim is high on a lot of guys' lists.

My view is that both genders will benefit if we can reduce the burden of HPV-related cancer and precancers. If the HPV vaccine continues to have a good safety record and is shown to have long-lasting effectiveness, it makes sense to vaccinate the boys and men too. After all, they are part of the problem.

Update on the HPV vaccine

I chose ob/gyn as my specialty partly because most women believe in preventive health care. It is very rewarding to work with patients who are willing to look ahead, and who have the foresight to accept inconvenience now for a future benefit.

Increasing acceptance of the vaccine to protect against the human papillomavirus (HPV) shows young women and mother-daughter duos definitely have that foresight. Women are  becoming informed about HPV and are using that knowledge to protect themselves.

In 2006, the FDA approved the HPV vaccine, Gardasil, for use in girls and young women ages 9 to 26. The vaccine protects against subtypes 6 and 11 (which cause almost all genital warts) and 16 and 18 (which cause 70% of cervical cancers).

The remaining 30% of cervical cancers are due to about a dozen other HPV subtypes not covered by the vaccine. It now appears that the current HPV vaccine offers some protection against these other subtypes.

A recent editorial in The Journal of Infectious Diseases discusses two new studies looking at HPV vaccine cross-protection. These studies showed partial protection against nonvaccine subtypes that could reduce the risk of cervical cancer by another 6% in vaccinated women.

Vaccination against HPV offers huge promise in both developed and developing countries. In developing countries, where women have not had access to Pap smears, cervical cancer is the second leading cause of cancer deaths in women.  The World Health Organization reports  80% of cervical cancer cases occur in low-income countries, where cervical cancer is a major cause of years of life lost in young and middle-aged women.

I saw this heartbreak firsthand while doing volunteer medical work in Jalapa, Nicaragua. One more than one occasion, a young woman with preteen children and far-advanced cervical cancer came to our clinic for help. We could offer comfort, but not a cure.

HPV vaccination is probably our best hope of reducing cervical cancer deaths worldwide. There are many challenges, including cost and logistics of delivering a three dose vaccination.

It also appears the prevalence of HPV subtypes varies in different parts of the world. HPV 16, the subtype that causes the most cervical cancers and precancers in the US, is less common in other parts of the world. Our current vaccine may not offer as much protection to women in developing countries.

The first trials of the HPV vaccine began in 2002, so some young women have been followed for more than 6 years. To date, the vaccine has a good safety record.

We don't yet know how long the vaccine protection lasts. Future trials will likely be conducted in women over 26 and in males. Soon, I'll look at issues involved in vaccinating males for HPV.