Multilevel Intervention Increased HPV Vaccination for Most Children

A multilevel intervention involving parent nudges and clinician reports increased human papillomavirus (HPV) vaccination for most children, though not for some of the most marginalized, a post hoc analysis of a cluster randomized trial found.

Vaccine initiation increased significantly for most children with the intervention (range of rates, 9.2% [95% CI 5.2%-13.3%] to 24% [95% CI 7.5%-40.6%]) except for Black children, and those living in rural settings or in highest deprivation areas by the Area Deprivation Index (ADI), reported Wei Yi Kong, PhD, of the division of epidemiology at Mayo Clinic in Rochester, Minnesota, and colleagues.

Vaccine completion also increased significantly for most children (range of rates, 19.4% [95% CI 5.5%-33.3%] to 31.2% [95% CI 12.1%-50.3%]), except for those in the highest ADI deprivation quartile, they wrote in JAMA Network Open.

Kong told MedPage Today that previous research has found that vaccine uptake and completion varies by race and ethnicity, rurality, and area-level socioeconomic disadvantage. HPV vaccination is vital for lowering the risk of HPV-attributable cancers.

Researchers found that with just usual care, HPV vaccine initiation and completion rates were increasingly lower as ADI quartiles increased but didn’t differ by race, ethnicity, or rurality (initiation: Cochran-Armitage test for trend [SE] -0.02 [0.01], P<0.001; completion: Cochran-Armitage test for trend [SE] -0.05 [0.01], P<0.001).

“Our findings indicate that mailing reminder letters to parents and monthly reports to healthcare professionals can improve human papillomavirus vaccination among 11- to 12-year-olds,” Kong said.

“We found that before the intervention, vaccine initiation and completion rates were not different by race and ethnicity or rurality but were significantly lower among those in areas of increasing socioeconomic disadvantage,” Kong said. “With the intervention, vaccine initiation and completion rates were higher for most 11- to 12-year-olds, and these improvements were not significantly different by their characteristics.”

Kong said that instead of a one-size-fits-all strategy for improving HPV vaccination, “we need to understand what drives vaccination among different adolescent populations and tailor our strategies to target those unique enablers and barriers to effectively reduce disparities in vaccine uptake,” and noted that “for adolescents living in the most socioeconomically deprived areas, more work is needed to identify which strategies are appropriate and effective to encourage their timely vaccination.”

Jessica Kingston, MD, an ob/gyn at UC San Diego Health, who was not involved with the study, told MedPage Today, said that since public health efforts have limited resources, it’s vital to funnel resources to areas of greatest need.

“It is not surprising that the multilevel intervention was less effective in increasing vaccine initiation and completion rates in children living in areas of highest deprivation,” Kingston said. “This mirrors what we see in those diagnosed with cervical cancer since they tend to be people who have never undergone screening or have been underscreened.”

Kingston added that future efforts should determine why the intervention had smaller positive impacts for children living in areas of highest deprivation and Black children, because “once the ‘why’ is understood, the ‘how to improve vaccination uptake’ will be more successful.”

The original stepped-wedge cluster randomized trial took place from April 2018 to August 2022 at six Mayo Clinic primary care practices across Minnesota. The multilevel intervention involved parent reminder/recall letters alerting parents that their children were due or past due for HPV vaccination, as well as audit/feedback reports that told healthcare professionals their vaccination rates. The study found that “both interventions doubled the odds of vaccine uptake compared with usual care and are more effective than each intervention alone.”

The study’s primary outcome was HPV vaccine initiation (first dose) and completion (second dose). This secondary analysis focused on the effect of the intervention by race and ethnicity, rurality, and ADI quartiles based on an area-level socioeconomic status composite derived from U.S. Census variables.

Analysis included 6,232 children between ages 11 (55.9%) and 12 (44.1%). Of the study participants, 72.2% were white, 9% were Black, 4.9% were Asian, and 2.3% were Hispanic. Most lived in urban areas (87.2%) and resided in ADI quartile 2 areas (44.8%).

As for limitations, Kong and team noted that because this post hoc analysis wasn’t part of the original trial design, they lacked statistical power among smaller strata, such as rural populations. Additionally, people who relocated during the trial were determined as not having a positive vaccination outcome, though this bias likely didn’t differ across trial arms. Clinical practices and patient demographics may not be widely generalizable and psychosocial characteristics of patients and providers may differ across practices. Potential vaccine hesitancy from the COVID-19 pandemic may have affected uptake in participant subgroups.