Vaccination rates against human papillomavirus have remained far lower than rates for other routine childhood and teen immunizations. But a big reason for those low rates comes from a surprising source.
It's not hesitant parents refusing the vaccine. Rather, primary care doctors treat the HPV vaccine differently from other routinely recommended immunizations, hesitating to recommend it fully and on time and approaching their discussions with parents differently, a study finds.
"The single biggest barrier to increasing HPV vaccination is not receiving a health care provider's recommendation," said lead study author Melissa Gilkey, an assistant professor of population medicine at Harvard Medical School. That's more of an issue, she says, than parents' decisions to refuse or delay HPV vaccination.
The problem? HPV infections are most commonly — though not always — transmitted sexually.
"These findings add to a growing literature that suggests that some providers find the interpersonal environment to be challenging when it comes to talking about HPV vaccination," said Gilkey. "Discomfort talking about sex appears to be a more salient factor" than safety concerns about the vaccine.
Nearly all cervical cancers result from HPV infections, which can also cause vaginal, vulvar, anal, penile or head and neck cancers. Although most strains of HPV infections go away on their own, a three-dose series of the vaccine protects against the strains responsible for an estimated 90 percent of HPV-related cancers.
The Centers for Disease Control and Prevention recommends it for all girls and boys ages 11 and 12 because it's most effective prior to first engaging in sexual activity.
The vaccine has not been out long enough to establish how much cancer it will prevent, since most cancers take years to develop after an HPV infection. But multiple studies have shown reduced rates among vaccinated people of the precancerous lesions that grow into cancer.
While regular screenings have reduced rates of cervical cancer in the U.S., the other HPV-related cancers do not have reliable screening tests.
Despite the safety and effectiveness of the vaccines, only 38 percent of teen girls and 14 percent of teen boys receive all three doses of the vaccine, the study noted, far below rates typically in the 80 and 90 percents for other vaccines.
"Although this study may surprise many, this very concern about provider hesitancy has been at the forefront of the CDC's concern," said William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt University School of Medicine. He said it started with strong pushback when the vaccine debuted, as many people focused on the mode of transmission rather than the disease itself.
Concerns that the vaccine would encourage promiscuity or would cause serious side effects dominated the conversation, but dozens of studies since have proven these concerns unfounded, Schaffner explained. "So many doctors were so bruised by all that parental reaction that now they're very tenuous," he said.
Gilkey's team sent out an online survey to 2,368 primary care physicians, about half pediatricians and half family doctors. Of the little over 1,000 who responded, 776 of them met the criteria and completed the survey. The results, published in Thursday in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research, found that more than a quarter of the respondents (27 percent) reported that they do not strongly endorse the HPV vaccine in talking with their patients' families.
They were also less likely to recommend on-time vaccination for boys than for girls. Nearly 2 in 5 doctors (39 percent) did not recommend on-time HPV vaccination for their male patients compared with 26 percent for female patients.
The starkest findings, however, related to how the doctors approach their discussions with parents. Only half recommend the vaccine the same day they discuss it, and 59 percent said they approach discussions by assessing the child's risk for contracting the disease rather than consistently recommending it to all children as a routine immunization.
"We need to make the vaccine not about sex but about routine cancer prevention," said Jennifer Edman, an assistant professor of women's primary care at Oregon Health & Science University. Other shots recommended around the same age include the Tdap (tetanus, diphtheria, pertussis) and meningococcal vaccines, but preventing cancer can seem distant at that age, Edman added.
"It is easy to fall into the trap of negotiating with either the parent or the teen," she said, "and the HPV vaccine can start to seem optional or of less immediate importance."
It's not that the physicians themselves believe the vaccine is unimportant. A full 99 percent of the respondents said they tell their patients that the HPV vaccine prevents cervical cancer and 89 percent explain it prevents genital warts, though just over half say it can prevent other cancers. It's how they perceive the attitudes of their patients' parents.
Nearly half of the physicians who responded (47 percent) believed that parents think of the HPV vaccine as only slightly important or not important at all for their preteen children. About a third somewhat or strongly agreed that they expected uncomfortable conversations with families about the vaccine, and a third said discussions were uncomfortable because HPV is a sexually transmitted disease. Yet these perceptions don't match up with reality, Gilkey said.
"We were surprised that physicians viewed parents as so unsupportive of HPV vaccination because research with parents themselves tells a somewhat different story," she said. "A lot of parents say that they just need more information. It seems clear that providers need communication strategies for recommending the HPV vaccine with greater confidence."
The result has been very low coverage for the only vaccine besides hepatitis B that can reduce cancers.
"The needle has moved from parental hesitancy to provider hesitancy," Schaffner said. "It's really saddened me because for a long time, an anti-cancer vaccine was a sort of a holy grail in medical research. This is a fabulous advance in women's and men's health, and we're letting young people grow into adulthood without that protection."
Tara Haelle is a freelance health and science writer based in Peoria, Ill. She's on Twitter: @tarahaelle