Parents are more likely to support laws that would make the human papillomavirus vaccine mandatory for school entry if their state offers opt-out provisions, however, the study's lead author cautioned that such opt-out provisions may weaken the effectiveness of the vaccine requirements.

The human papillomavirus (HPV) causes most cases of cervical cancer and a large proportion of vaginal, vulvar, anal, penile, and oropharyngeal cancers. The U.S. Centers for Disease Control and Prevention (CDC) recommend that boys and girls receive the three-dose HPV vaccination beginning at age 11 or 12. However, as of 2014, only 40 percent of girls and 22 percent of boys ages 13 to 17 had completed the HPV vaccine series, according to CDC statistics.

Calo said previous research has shown that school-entry requirements have contributed to high uptake rates for vaccinations such as Hepatitis B, Tdap, and MMR. Since 2006, half of U.S. state legislatures have introduced measures to add HPV to the list of required vaccines, however, most measures were rejected, often due to parental disapproval or ethical, political, or legal concerns, Calo said. Presently, only Virginia, Rhode Island, and the District of Columbia require the HPV vaccine for school enrollment, and all allow parents to opt out.

In order to evaluate parental support for making the HPV vaccine mandatory for school entry, Calo, Brewer, and colleagues conducted a web-based survey of 1,501 parents between November 2014 and January 2015. To be eligible for the survey, parents had to have at least one 11- to 17-year-old child living primarily in their household.

The survey stated, "Some states are trying to pass laws that would require all 11- and 12-year-olds to get HPV vaccine before they are allowed to start 6th grade." Parents were then asked whether they agreed with the statement, "I think these laws are a good idea." Overall, 21 percent of parents agreed that such laws are a good idea, and 54 percent disagreed.

Twenty-five percent of respondents said they neither agreed nor disagreed with the statement; Calo said this group may benefit from public education about HPV vaccination and, as they learn about the benefits of vaccination, be more likely to support school-entry requirements.

Respondents who said they disagreed that the laws are a good idea then received this follow-up statement: "It is okay to have these laws only if parents can opt out when they want to." When the opt-out provision was added, 57 percent of respondents agreed that the school-entry requirements are a good idea, and 21 percent disagreed.

The study also identified several factors that influenced approval of HPV vaccine requirements. Nearly one-third (32 percent) of respondents felt that the vaccine was being promoted to make money for drug companies and only 40 percent felt that the vaccine was effective in preventing cervical cancer. Calo said changing some of those perceptions would be beneficial for improving HPV vaccination rates and for legislating school-entry requirements.

Calo cautioned that opt-out provisions could weaken the overall effectiveness of vaccination if large numbers of families opted out. "Any process for requesting an opt-out should have an educational component and encourage parents to carefully consider their decision," he said.

"HPV vaccination saves lives," Calo said. "We have an unprecedented opportunity to prevent thousands of HPV-associated cancers through vaccination and unfortunately, we are missing that opportunity."

Brewer noted the findings suggest that states should consider school-entry requirements for HPV vaccination once states have implemented other approaches that have proven successful in raising vaccination rates, such as centralizing vaccination reminders in state health departments, focusing quality-improvement visits to providers on HPV vaccination, and training physicians to use announcements to introduce vaccination.

The authors noted that a limitation of this study is that it asked about hypothetical school-entry requirements, rather than actual laws, and did not describe the scope of opt-out provisions. The researchers said parents' opinions could differ if they were discussing actual legislation, and may vary depending on whether the opt-out provisions were based on medical, religious, or philosophical reasons.

This study was funded by a grant from the Merck Sharp & Dohme Investigator Studies Program. Brewer has received HPV vaccine-related grants from or been on paid advisory boards for Merck Sharp & Dohme and Pfizer. Brewer is also chair of the National HPV Vaccination Roundtable.

Article: Parents' Support for School-Entry Requirements for Human Papillomavirus Vaccination: A National Study, William A. Calo, Melissa B. Gilkey, Parth D. Shah, Jennifer L. Moss, and Noel T. Brewer, Cancer Epidemiology, Biomarkers & Prevention, doi: 10.1158/1055-9965.EPI-15-1159, published online 19 August 2016.