Dear Vaccine Smarts,
Our family physician recommended that my daughter and son receive the HPV vaccine. However, my brother tells me that the vaccine’s anti-cancer claims are fraudulent. I’m not sure whether I should vaccinate my children. Is my brother right?
Thanks for writing. There is only a small kernel of truth to what your brother says. Both your children can benefit from the HPV vaccine, and we recommend you have them vaccinated.
A lot is known about the history of the human papilloma virus infection and cervical cancer (the original target of the HPV vaccine). The HPV types that infect the cervix are usually spread through sexual contact. Over 99 percent of cervical cancer is caused by HPV. Most types can’t cause cancer, but two types, HPV 16 and HPV 18, together cause about 70 percent of the cases. They are the types covered by the current vaccines.
Upward of 90 percent of cervical HPV infections are wiped out by the immune system within a year or two. Of the remaining 10 percent, slightly more than half are eliminated by the immune system over a much longer period. The remaining infections, if left untreated, can cause cancer.
This slow progression over decades is the basis of the Pap smear, which samples cells from the cervix looking for the abnormalities caused by HPV. If the abnormalities are severe enough, procedures are performed to remove or kill the abnormal cells so they cannot become invasive cancer.
Here’s where your brother is only slightly correct. The studies weren’t designed to look at cancer itself — but there’s a good reason why.
During the studies’ clinical trials, some women received the HPV vaccine while others received a placebo vaccine. The women who developed precancerous cells were treated.
It would have been unethical to allow the research volunteers to develop cancer.
The clinical trials did demonstrate that the vaccines prevent infection and the formation of cells that could become cancer. If you prevent the precancerous cells then you prevent the cancer. So they really are “anti-cancer vaccines.”
Some people argue that we don’t need a vaccine because PAP smears provide enough protection. Unfortunately, the present system of well-woman exams misses some cancers, and some women don’t have exams or PAP smears regularly.
The American Cancer Society estimates that in 2012, over 12,000 women in the United States were newly diagnosed with cervical cancer, while slightly more than 4,000 died from the disease.
The vaccines could have prevented over half of those cases if all of the women had been vaccinated before becoming infected with HPV.
The vaccine helps prevent the majority of abnormal test results. Women with a history of abnormal PAP smears can speak to the emotional distress as well as the discomfort of the procedures to remove abnormal cells. Most women should want the vaccine since it reduces the possibility of having an abnormal Pap smear.
The currently licensed HPV vaccines are Cervarix and Gardasil. Both cover HPV types 16 and 18, thereby reducing the risk of cervical cancer as well as cancers of the vagina, vulva, anus and penis. Gardasil also covers HPV types 6 and 11, which together account for about 90 percent of genital warts. While penile cancer is extremely rare, men benefit primarily from the prevention of anal cancer and genital warts; therefore, only Gardasil is recommended for males.
Again, both your son and daughter can benefit from the HPV vaccine. You should have them vaccinated.
Dr. Richard Rupp is a pediatrician and member of UTMB’s Sealy Center for Vaccine Development. Bridget Hawkins, Ph.D., is the assistant director of the Sealy Center for Vaccine Development. This column is supported by a UTMB President’s Cabinet Award to provide information about vaccines. Visit www.utmb.edu/scvd/vaccinesmarts for more information.