Across the main specialties involved in HPV vaccination, the prevalence of “always” recommending vaccination was lowest for early adolescents (34.6%) and increased slightly to ~50% for middle (52.7%) and late adolescents/young adults (50.2%). This practice is not in compliance with ACIP recommendations which designates girls aged 11-12 years as the primary target, ideal age group for routine vaccination [1
]. The lower prevalence of recommendation for this age group is consistent with findings from previous studies [30
], and is lower than rates reported for middle adolescents which ranged from 36% to 64% in other studies [30
]. These results point to the need to intervene with physicians as one approach to increase dissemination of HPV vaccination in females.
The rationale for targeting early adolescents is to deliver the vaccine prior to sexual debut and first HPV exposure [21
]. In a recent analysis of the Youth Risk Behavioral Surveillance data, 5.9% of students reported engaging in sexual intercourse before age 13 [33
]. Additionally, younger age groups are ideal to target for HPV vaccination given the frequency of preventive care physician visits and that providers who see this age group are most experienced in delivering vaccines [34
]. Thus, the results indicate that less frequent recommendation to younger females represents a missed clinical opportunity to provide both individual and population level benefits of HPV vaccination.
Despite consistent recommendations across professional organizations of each specialty [35
], vaccine recommendation rates varied by provider specialty. Peds were significantly more likely than FPs and OBGYNs to “always” recommend HPV vaccination for almost all female age groups. In a study of factors associated with HPV vaccine series initiation and completion among adolescent females ages 9-18, there were no differences in series initiation between Peds and FPs [38
]. However, in our study FPs were least likely to recommend HPV vaccination. Differences in results across physician studies may reflect variability in survey question design or other interventions in place at the time of the survey. For example, Dempsey et al. [5
] observed that “visit type” was most strongly associated with HPV vaccination. In the current study, vaccination recommendation was not evaluated by visit type and may account for some of the specialty specific differences in our study given that FPs are 50% less likely to see adolescents for preventive care visits compared to Peds [34
]. Additionally, during 6 of the 15 months of the Dempsey et al. study, Family Medicine clinics (but none of the other specialties) participated in an intervention that provided automated computer reminders about HPV vaccination [38
Older adolescent and young adult visits tend to shift from the Peds care setting to that of FPs and OBGYNs [34
]. Our study found that OBGYNs were more likely than FPs to recommend vaccination to middle and late adolescent/young adult patients. This may also reflect the nature of visits to FPs versus OBGYNs. An analysis of National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey data conducted prior to HPV vaccine availability indicated that 35% of preventive visits made by females ages 18-21 were to OBGYNs; the same report found only 1-3% of immunizations were received from OBGYNs (or other subspecialists) [34
]. However, if the pattern of visit type by specialty remained consistent (i.e., FPs for problem-focused and OBGYN for preventive visits) since HPV vaccine availability, then perhaps the clinical opportunity to recommend HPV vaccination for late adolescent females is more likely to occur in OBGYN visits.
In addition to specialty, physician demographic characteristics including age and ethnicity were significantly associated with vaccine recommendation. Physicians aged 40-49 years were more likely to recommend HPV vaccination than physicians in younger or older age groups. It is possible that providers in this age group have achieved a sufficient level of clinical autonomy, but are still open to the adoption of new innovations and technologies in their clinical practice. Physicians who self-identified as Hispanic/Latino were more likely than non Hispanic/Latino providers to always recommend HPV vaccination to early adolescents. Given that Hispanic women have higher rates of cervical cancer incidence compared to other races/ethnicities [39
] and Hispanic physicians are more likely to provide care to Hispanic patients [40
], they may be more sensitized to the importance of vaccines for cervical cancer prevention.
Compared to physicians who reported high perceived barriers to vaccination, those who reported low perceived barriers were more likely to recommend vaccination to early adolescents. This finding is aligned with previous research that found several individual barriers, including concerns about adding another vaccine to the vaccine schedule and the time needed to discuss HPV vaccination with parents, were significantly associated with physicians not strongly recommending vaccination of girls aged 11-12 [41
Policy-level factors that impact physician recommendation of HPV vaccination include state vaccine financing programs’ coverage of immunization [42
]. In the current study, VFC provider status was examined as a means for assessing the impact of state vaccine financing on physician recommendation of HPV vaccine, and results indicate VFC providers were more likely than non-VFC providers to report always recommending HPV vaccine to early adolescent patients. The VFC program provides ACIP-recommended vaccines to eligible children up to age 18, who meet at least one of the following criteria: Medicaid eligible, uninsured, underinsured, or American Indian or Alaska Native [43
]. VFC states (n=36) provide vaccines only for VFC providers choosing to enroll. Physicians who enroll as VFC providers may be responsible for maintaining separate vaccine stocks for VFC-eligible and non-eligible patients. Thus, providers willing to take on this additional responsibility may represent those groups with greater motivation to recommend vaccination [42
]. It is plausible that an intervention to increase physicians’ participation in the VFC program will increase physician recommendation of HPV vaccine.
Finally, it should be noted that the FDA approved the HPV vaccine for use in males after the current study was conducted [44
]. Prior to FDA approval, Weiss and colleagues [45
] surveyed FPs and Peds about their attitudes and perceptions of vaccinating males against HPV. Physicians were asked the frequency with which they recommended HPV vaccine to their female patients and if they would recommend the vaccine to males if recommended by the ACIP and covered by insurance. Results suggest that more physicians would “often” or “always” recommend the vaccine for males (24.1%) than females (18.1%) aged 9-10 years (P
< 0.001), but more physicians would recommend the vaccine to females than males for the 11-12 and 13-18 age groups (P
< 0.001). For ages 19-26, no statistically significance by patient gender was observed. Further research examining physicians’ actual recommendation of HPV vaccine to their male patients is needed.
To our knowledge, this is the first nationally representative survey of US provider recommendation of HPV vaccination. There are notable strengths in the present study. First, our study population is based on a sample of all US licensed physicians. Previous physician studies of actual vaccination practices have been limited by geography and/or membership to a particular professional organization or society [30
]. Second, our survey response rate (~68%) exceeds any previous study of actual physician recommendation of HPV vaccination yielding response rates below 20% [30
]. This response rate among a nationally representative sample of physicians enhances the generalizabilty of our findings to all US physicians practicing in the specialties studied. Third, we were able to make important comparisons of recommendation practices by both patient age group and provider specialty, allowing for a more precise estimate of HPV vaccination recommendation. Additionally, these data serve as an important baseline measure of recommendation of HPV vaccination to evaluate time trends post-vaccine licensure.
This study also has limitations. The initial sampling frame may not have included all eligible physicians. However, the AMA Masterfile [25
] contains data on 100% of allopathic and 93% of osteopathic physicians, irrespective of membership to the AMA or any other professional organization [46
]. Since ~32% of physicians did not respond to the survey, results may be more representative of physicians with stronger opinions about HPV vaccination. However, our overall response rate far exceeds any previous national or population-based study of HPV vaccine recommendation to date. We did not observe whether physicians actually recommended vaccination to their patients and it is possible that respondents reported socially desirable responses with respect to practice behaviors. However, the anonymity of the survey likely reduced this bias. There is further evidence that bias was unlikely given the range of responses on our primary outcome variable of interest. Our survey was conducted prior to the availability of the bivalent HPV vaccine. Thus, it is possible that responses to certain questions (e.g., barriers associated with vaccination) may differ based on the type of vaccine a provider elects to provide to their patients. Finally, we used “always” to group physicians who reported recommending vaccination >75%-100% of the time.