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When people hear about vaccine denial, they most often think about parents who are refusing to vaccinate their children. But there's another type of vaccine refusal, and it's important that we not ignore that, too. Doctors sometimes promote the use of some vaccines with less enthusiasm than others. Sometimes, they don't talk about them at all.

This occurs most often with the herpes simplex virus, or HPV, vaccine. Our suboptimal immunization rates with this vaccine, and the behaviors of the physicians who might be contributing to that, have consequences. That's the topic of this week's Healthcare Triage.

This is based largely off a post Aaron wrote for the Upshot. Links to further reading can be found there:

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When people hear about vaccine denial, they most often think about parents who are refusing to vaccinate their children, but there's another type of vaccine refusal and it's important that we not ignore that, too.  Doctors sometimes promote the use of some vaccines with less enthusiasm than others.  Sometimes, they don't talk about them at all.  This occurs most often with the Human Papillomavirus, or HPV vaccine.  Our sub-optimal immunization rates with this vaccine and the behaviors of the physicians who might be contributing to that have consequences.  That's the topic of this week's Healthcare Triage.


One of our first videos was on the HPV vaccine, and you should go watch it, but here's a recap.  HPV is a sexually transmitted illness that is very, very common.  So much so that almost all sexually active people will get at least one of the more than 40 types at some point in their lives.  The CDC estimates that almost 80 million Americans are currently infected with HPV and that about 14 million people will become newly infected this year.  

Most people don't suffer any real negative health consequences, but some do.  About 1% of those infected will have genital warts at any given moment.  More importantly, about 17,500 women and 9,300 men will be affected by cancers HPV causes each year.  These include cervical, (?~1:22), anal, vaginal, and penile cancers.  This is preventable.  The CDC recommends that all children, boys and girls, begin receiving the first of three vaccinations when they are 11-12 years old.  The reason we start that young is because it's important the kids be immune before they become sexually active.  Once they're exposed to the virus through sexual activity, it's too late to immunize.

Let's also be clear.  Regardless of what some presidential candidates say, the vaccine is safe.  The scary e-mails and internet horror stories you've read can easily be explained away, as we did in our previous video.  The vaccine works and it's not dangerous.

Our immunization rates for HPV are far short of other vaccines.  Last year, fewer than 42% of adolescents age 13-17 years old had received at least one dose of the HPV vaccine, but even this rate of vaccination has made a difference.  A study published two years ago in The Journal of Infectious Diseases examined the prevalence of HPV infections in females both before and after the vaccine was introduced.  Among adolescent girls age 14 to 19 years old, the prevalence of HPV dropped from 11.5% before 2006 to 5.1% after.  This drop could not be accounted for by changes in demographics or sexual activity.  

This remarkable reduction in HPV prevalence occurred even though only about a third of girls age 13-17 had received all three doses of the vaccine in 2010.  CDC director Tom Friedman estimated then that if we could increase vaccination rates to 80%, far lower than we see in most other vaccines, we could prevent 50,000 cases of cervical cancer in girls alive today.

Certainly policy is partly to blame here.  While states pretty much mandate all childhood vaccines as necessary for entry into school, fewer focus on diseases affecting adolescents.  However, all states and DC require immunity to varicella.  47 states and DC require vaccination against Hepatitis B.  29 states and DC require it for meningococcus.  Only two states and DC require vaccination against HPV.  Rhode Island only joined Virginia and DC in August of this year.

Parental and adolescent health beliefs certainly come into play, too.  Myths about the safety of the HPV vaccine persist regardless of overwhelming evidence that the immunization is safe.  How giving the vaccine may influence sexual activity is also a concern, despite many studies showing that girls who receive the vaccine do not engage in more unsafe sexual behavior after receiving the vaccine than before.

Doctors bare responsibility here as well, though.  A recent study by Melissa Gilkey, a behavioral scientist at Harvard Medical School, surveyed pediatricians and family physicians to examine their communication practices around vaccines.  She found that more than a quarter of doctors don't endorse the HPV vaccine strongly.  About a quarter did not make timely recommendations for girls, and almost 40% didn't make timely recommendations for boys.  Only half recommended same day vaccinations, and almost 60% used a risk-based approach, recommending the vaccine to patients they thought were more likely to be sexually active.

This is, of course, a problem.  If a child is already sexually active, it's probably too late to protect them.  Gilkey's prior work found that physicians felt that talking to patients about the HPV vaccine took significantly more time than other vaccines, which made them less likely to engage.  Further, many physicians believe parents don't want the HPV vaccine.  

While 3/4 of doctors reported receiving parental support for T-Dap for instance, only 13% believed parents supported the HPV vaccine.  That's not the case.  A study published last year in the journal Vaccine found that doctors underestimated how important vaccines were to parents and overestimated parental concerns about how many shots their kids were getting.

Other research shows that the most common reason for adolescents not receiving the HPV vaccine isn't parental denial.  It's a lack of physician recommendation.  Even if there are parental concerns, it's up to the physician to address them.  One of the nation's preeminent experts in HPV vaccine behavioral research, Greg (?~5:28), has an office in the same building as me.  His research has also found physician communication to be a significant predictor of HPV coverage.

A point that (?~5:36) has made repeatedly, however, is that the number of behavioral studies of the HPV vaccine is far, far greater than for any other vaccine.  There's something different about this vaccine that causes people to behave differently when discussing, considering, and administering it.  The elephant in the room is, of course, sex.  This vaccine prevents a sexually transmitted infection, and a pervasive belief exists that when parents or even doctors give the vaccine, they are condoning sexual activity in young adolescents.  This is of course not true.  Many kids engage in sexual activity with or without the vaccine.  We administer the immunization to protect them regardless.  Moreover, research is abundant in this domain as well.

A 2012 study published in JAMA Pediatrics found that girls perceived no less need for safer sexual behaviors after getting the HPV vaccine.  A 2014 cohort study of more than 260,000 girls found that those who received the HPV vaccine were no more likely to get pregnant or to contract a non-HPV related sexually transmitted infection than girls who were unvaccinated.  This confirmed findings from a smaller cohort study from 2012 that found the same thing.  

We need to stop treating this vaccine differently.  Professional vaccine denialism is just as consequential as parental.  The good news is that all of this is fixable.  Research consistently shows that doctors have a lot of influence on parents' decision-making about HPV vaccination.  They should just talk about it, as they do all other vaccinations in a straightforward, unambiguous way.  

As Ms. Gilkey told me, "Just by letting parents know that HPV vaccination is very important for all 11 and 12 year olds, physicians and other vaccine providers can do a lot to overcome the barriers that have kept coverage low in the United States."

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