Universal coverage with the HPV vaccine would save thousands of lives in the US each year. Why are we at ~40%?
I suspect that most persons reading this article, found on a Web site for physicians, would place themselves squarely in the pro-vaccine camp. Most of us would agree that the anti-vaxxer's "dirty little secret" is that they simply do not understand science. Emotion trumps rational thinking. An anecdotal adverse event that affects one individual has more impact than a well-designed study involving tens of thousands. But, before you begin feeling smug about your more intellectual approach to vaccines, hold off until we talk below about one of our (pro-vaxxers) own dirty little secrets, below.
The rationale for vaccines fall into three groups:
1. Some vaccines don't really have much impact on reducing deaths and permanent sequelae but are still valuable because of their economic impact and reduction in misery. The rotavirus and varicella vaccines fall into this category. Before their widespread use, about one hundred Americans would die per year from complications of chickenpox and fewer than one hundred deaths per year were attributed to infections from rotavirus. But since these diseases permeate the population, causing a lot of missed work and school days, not to mention misery, vaccination against them is clearly worthwhile.
2. Vaccines in a second category prevent serious, but rare, complications of infectious diseases. In the prevaccine era, fewer than 600 cases per year of tetanus were reported, but mortality was high, at over 80%. Meningococcal disease was uncommon in the prevaccine era, less than 3000 cases a year with about 300 deaths. But most of us think that death is a complication worth avoiding with a vaccine if possible.
3. The third category of vaccines is the most important. These vaccines prevent a lot of deaths and serious sequelae by reducing the risk of infectious diseases that are both common and deadly. Vaccines against measles, polio, HIB, and pneumococcal fall into this category. This is the group of vaccines we should be not just recommending, but should be strongly encouraging our patients to accept.
US vaccination rates with all the vaccines I mentioned above are excellent. But there are 2 other vaccines in that important third category-against diseases common and deadly-that many providers do not strongly encourage. And therein lies a pro-vaxxer's dirty little secret. Universal coverage with HPV and influenza vaccines would prevent thousands of deaths in the US every year.
Let's look specifically at HPV disease and Gardasil.
Is infection with HPV common? The CDC's Pink Book estimates that 79 million Americans are currently infected with 14 million new cases per year. Yes, it is common, but fortunately most infected individuals will clear the virus never having known they were infected. Unfortunately, a small percentage of infections do not clear and can lead to cancerous changes.
Is infection with HPV deadly? HPV is responsible for 100% of cervical cancers, 88% of anal cancers, 63% of penile cancers, 40% of head and neck cancers, 74% of vaginal cancers and 30% of vulvar cancers. If you add the numbers up, universal HPV vaccination could prevent 10,000 deaths a year from cancer in the United States.
Are we doing a good job getting our adolescents vaccinated? In 2010 32% of American females had completed the 3-dose HPV series and by 2014 we got the number up to 40%. How does this compare to other countries with more limited medical resources?
1 Which of the following countries had a lower 3-dose HPV series immunization rate among vaccine-eligible females as compared to the US in 2010?
Answer: A. France had a rate below 30%. (NB: Rwanda [D] led the list at 93% of vaccine-eligible females having complete the 3-dose series.)
Are you embarrassed by the answer? I am. One reason for the poor rate in the US is the very poor rate of provider recommendation. In a study by Gilkey et al published in 20151 researchers polled 700 pediatricians and family practice (FP) physicians and about 40% did not “strongly recommend” HPV vaccine to 11-12-year-old females. The numbers were even worse with 11-12 year old males--less than 50% strongly recommended the vaccine. Multiple studies with a variety of vaccines have shown that one of the strongest predictors of vaccine acceptance is provider recommendation.
One could argue that pediatricians don't push the vaccine since we don't see HPV disease other than genital warts. Family practice doctors, on the other hand, do have to deal with abnormal pap smears and the cancers noted above. Surprisingly, in the above mentioned study FPs were less likely as compared to pediatricians to recommend the vaccine.
Are you part of the problem? Do you want to be part of the solution? In Part 2 I will specifically address the most effective techniques to get parents to agree to HPV vaccination.