1. Nalley, Catlin

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Researchers tracked trends in human papillomavirus (HPV) vaccine hesitancy for several years and found that parental vaccine hesitancy declined from 2010 to 2012; however, since then it has remained stable overall through 2019. These findings were recently presented during the virtual 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved (Abstract PR-10).

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The study also showed that vaccine hesitancy is still very high in the U.S., with almost two-thirds of the parents included in the study remaining hesitant about the HPV vaccine as of 2019, according to study author and presenter Eric Adjei Boakye, PhD, Assistant Professor in the Department of Population Science and Policy at Southern Illinois University School of Medicine.


The HPV vaccine was first approved for U.S. adolescents in 2006, and since then teen vaccine uptake is primarily a decision made by parents. "Parental skepticism regarding the HPV vaccine has been a known driver of suboptimal vaccine uptake in the U.S.," Boakye said during his presentation, noting that this may have been exacerbated by societal anti-vaccine sentiments, medical mistrust, and social media disinformation.


"However, what is lacking is whether those characteristics have changed since the vaccine was licensed and recommended," he stated. "This study, therefore, looked at the characteristics of patients who are hesitant [to vaccinate]."


Methods, Findings

The researchers used data from the 2010 to 2019 National Immunization Survey-Teen (NIS-Teen) to identify 16,383 adolescents who had not received any dose of the HPV vaccine. To assess vaccine hesitancy among parents, they asked, "How likely is it that your teen will receive HPV shots in the next 12 months?" Parents responding with "not too likely," "not likely at all," or "not sure/don't know" were considered to be vaccine hesitant.


"The characteristics that were analyzed in the study included mother's age, mother's marital status, and mother's educational level," said Boakye. "We use joinpoint regression to estimate the yearly increases or decreases in the vaccine hesitancy for these characteristics."


The data showed that overall HPV vaccine hesitancy decreased from approximately 69 percent in 2010 to 63 percent in 2019, Boakye reported. However, the researchers observed increased hesitancy, or hesitancy that improved then stalled, among several subgroups.


Average vaccine hesitancy for mothers with male adolescents decreased 6.17 percent annually from 2010 to 2012, but then remained stable from 2012 to 2019, according to Boakye. Among mothers with children of Hispanic race, he reported an average hesitancy decrease of 6.24 percent per year from 2010 to 2013, but an average increase of 1.19 percent per year from 2013 to 2019. The researchers observed no significant changes for children of other races.


When looking at a mother's age, Boakye and colleagues found that, for mother's aged 35-44, average vaccine hesitancy decreased 5.88 percent from 2010 to 2012. It then remained stable from 2012 to 2019. Among mothers older than 45 years, the average vaccine hesitancy from 2010 to 2013 decreased 3.92 percent and then remained stable through 2019.


Mothers with a college degree or higher had a 6.03 percent average decrease in vaccine hesitancy from 2010 to 2012. In comparison, mothers with a high school diploma had a 6.24 percent average decrease for the same time period. This trend remained stable among both groups after 2012.


The researchers also observed the average vaccine hesitancy among married mothers decreased at 5.07 percent annually from 2010 to 2012 and then remain stable through 2019, Boakye reported.


Boakye acknowledged that there are limitations to this research, the main one being that it is a cross-sectional study rather than a prospective cohort. "Vaccine hesitancy was measured only once, and so it's possible that parents might have changed their mind later and it's not captured [here]," he explained, while also noting that different parents were used each year. Since the same parents were not followed over the 10-year time period, researchers could not evaluate whether their opinions on vaccination had changed.


Implications, Discussion

Summarizing their findings, Boakye reiterated that, as of 2019, almost two-thirds of parents remain hesitant when it comes to the HPV vaccine. This underscores ongoing vaccine hesitancy in the U.S.


During a discussion with session chair Khadijah A. Mitchell, PhD, of Lafayette College, Boakye shared some of the key reasons parents may be hesitant for their child to receive the HPV vaccination. These reasons include a belief that the vaccine is not necessary, a lack of knowledge, and concerns about safety.


This research, according to Boakye, draws attention to the need for public information campaigns that target parents who are vaccine hesitant. He also noted the potential value of culturally tailored messages in the Hispanic population, especially given the higher incidence of cervical cancer among this patient population.


"The HPV vaccine is very safe, and it is effective at preventing HPV-associated cancers. Over 135 million doses have been administered in the U.S. alone with very few reported adverse effects," Boakye noted in a statement, urging parents to be cognizant of disinformation on social media. "Do not trust everything you read on the internet or social media platforms. If you are in doubt or have a question, please talk to your doctor.


"Our study supports efforts to develop interventions to increase vaccine confidence among parents through provider recommendations [and] interventions to strengthen public trust in the health care system in general," concluded Boakye, while emphasizing that mistrust of the system is one of the main reasons for vaccine hesitancy.


Additionally, he noted that this research highlights the importance of eliminating or reducing barriers to getting the HPV vaccine, as well as the need to tackle disinformation, especially on social media platforms.


Catlin Nalley is a contributing writer.