The prevalence of HPV infections in teenaged girls has dropped 56 percent since the introduction of a vaccine in 2006.
The prevalence of human papillomavirus, or HPV, infections in teenaged girls between 14 and 19 years of age has dropped 56 percent since the introduction of a vaccine in 2006, the Centers for Disease Control and Prevention reported Wednesday. Despite the controversy surrounding the vaccine, HPV vaccination has been found to be overwhelmingly effective, according to a CDC study published in the June issue of The Journal of Infectious Diseases.
The study, conducted by Dr. Lauri Markowitz at the CDC, used the National Health and Nutrition Examination Survey to compare the proportion of women aged 14 to 59 with certain types of HPV before and after the introduction of HPV vaccination. HPV infection rates fell from 11.5 percent to 5.6 percent.
“This report shows that HPV vaccine works well, and the report should be a wake-up call to our nation to protect the next generation by increasing HPV vaccination rates,” said CDC Director Thomas Frieden. “Unfortunately only one-third of girls aged 13-17 have been fully vaccinated with HPV vaccine. Countries such as Rwanda have vaccinated more than 80 percent of their teen girls. Our low vaccination rates represent 50,000 preventable tragedies – 50,000 girls alive today will develop cervical cancer over their lifetime that would have been prevented if we reach 80 percent vaccination rates. For every year we delay in doing so, another 4,400 girls will develop cervical cancer in their lifetimes.”
The genital human papillomavirus
About 79 million Americans — or slightly more than 1 in every 4 Americans — have contracted the human papillomavirus, with most of those infected being teenagers and adults in their early 20s. Approximately 14 million new cases of HPV infection occur each year. This, according to the CDC, results in about 19,000 new cases of cancer — most commonly cervical cancer — among American women every year. Among men, HPV infection leads to about 8,000 new cases of cancer, usually in the throat, every year.
Michael Douglas came to the forefront of the HPV debate earlier this month when, in an interview with The Guardian, he drew a link between oral sex, male cases of HPV and throat cancer. Current scientific evidence neither supports nor refutes this, although the connection between HPV strain 16 and throat cancer is confirmed. In a recent study of 1,316 patients with oral cancer, 57 percent of the patients were also HPV-16 positive.
The vaccines commonly available in the United States are Cervarix and Gardasil. Cervarix, a female-only vaccine, is effective against HPV-16 and HPV-18 and is issued as a check against cervical cancer. Gardasil, which has no gender restriction, works against HPV-6, HPV-11, HPV-16 and HPV-18. The vaccines, which are delivered in a three-shot immunization package over six months, have been found to be overwhelmingly effective, even if the patient doesn’t receive all three shots.
“The decline in vaccine type prevalence is higher than expected and could be due to factors such as to herd immunity, high effectiveness with less than a complete three-dose series and/or changes in sexual behavior we could not measure,” said Markowitz. “This decline is encouraging, given the substantial health and economic burden of HPV-associated disease.”
The genital human papillomavirus is the most common sexually-transmitted infection in the world, with more than 40 detected strains. Most people who have the infection do not realize it. HPV can be transmitted via oral-to-genital or genital-to-genital contact, and it is possible to have more than one strand of HPV active within a carrier at the same time. In extreme cases, HPV can be transmitted during pregnancy. The infected child can develop recurrent respiratory papillomatosis, or warts inside the throat. There is no known cure for the infection.
Vaccinations and politics
Despite the prevalence of the disease and the effectiveness of the vaccine, HPV vaccination is highly controversial in the United States. Routine vaccination is recommended starting at age 11 for both boys and girls, but only about half of all girls and a small percentage of all boys have received even the first HPV vaccine shot.
The CDC says the HPV vaccination is essential before a person becomes sexually active. American vaccination rates are low in part because medical providers have not recommended them strongly enough. Other factors include parental objections to vaccinating non-sexually active children against a sexually-transmitted infection, concerns about the safety of the vaccine, and a lack of understanding of the threat of the infection to males.
The CDC has not been able to link any serious health problems or deaths to the vaccine, said Dr. Cindy Weinbaum, a medical epidemiologist, to NBC News. The vaccine could cause fainting, dizziness and soreness at the injection site — all considered minor and normal side effects of all injections.
In 2007, Gov. Rick Perry (R-Tex.) took the unprecedented move of issuing an executive order to require all sixth-graders in Texas to receive HPV vaccinations as part of the vaccination package public school students are required to take in order to enroll. The move was almost immediately overturned by the Texas Legislature and was vehemently attacked during the Republican presidential primaries.
“I will tell you that I had a mother last night come up to me here in Tampa, Florida, after the debate,” Rep. Michele Bachmann (R-Minn.) said. “She told me that her little daughter took that vaccine, that injection, and she suffered from mental retardation thereafter.”
Former Sen. Rick Santorum (R-Penn.) also criticized Perry’s executive order, describing it as “having little girls inoculated at the force and compulsion of the government.”
The vaccination would not have been purely compulsory, as parents had the right to opt out on behalf of their children.
In Virginia, similar legislation made the vaccine available, free of charge, without any requirements to use it. The state legislature later ended the program. According to the Virginia Department of Health, over 8,000 girls were immunized under the state vaccination program in the four years it existed.
“I think for decades we have hoped for a vaccine against cancer, and this is the first time we have that situation,” said former state Sen. Mary Margaret Whipple (D-Arlington), who voted to uphold the vaccine mandate in Virginia. “I’m satisfied with the Virginia system, by which parents can opt out easily if they choose to.”
While Perry’s efforts in Texas were suspect — the Gardasil vaccine is made by Merck, which has given more than $30,000 in campaign contributions to Perry since 2000, and Perry issued the requirement as an executive order despite legislative objections — it ultimately served the public good.
“Given the high cost of the vaccine, it’s critical to make sure it’s accessible for the uninsured,” said Jessica Honke, policy director for Planned Parenthood Advocates of Virginia. “If the immunization wasn’t required for girls entering sixth grade, there would be no incentive for the health department to make it available and accessible.”
“The HPV vaccine has been shown to be safe and well-tolerated based on multiple medical reports that have been submitted through government databases,” Dr. Renata Arrington-Sanders, a professor at Johns Hopkins University medical school, told the Huffington Post. “It’s unfortunate that this particular vaccine is surrounded by a lot of controversy just because it’s been labeled as an STD-prevention vaccine. We have similar vaccines, such as one for hepatitis B, that are also used in a mandated approach and have shown very successful rates with prevention.”
While many would argue that mandating a vaccination is tyrannical, others feel it is simply an issue of public health.
“This is not a political issue — it’s a public safety issue,” Honke said to the Huffington Post. “It comes down to the fact that the HPV vaccination is the best way to decrease the number of young men and women who would otherwise get the HPV disease.”