Low Coverage of HPV Vaccination in the National Immunization Programme in Brazil: Parental Vaccine Refusal or Barriers in Health-Service Based Vaccine Delivery?

The quadrivalent human papillomavirus (HPV) vaccine was introduced into the National Immunization Programme (NIP) in Brazil in 2014. It has been argued that the low uptake of the HPV vaccine in Brazil may be due to fear of adverse reactions (following media reports of neurological symptoms in clusters of girls in Brazil), parental vaccine hesitancy, and/or logistical challenges to vaccinating adolescents at healthcare centres. However, there are no data available to indicate which one of these reasons (or whether combination of them) is to blame. The aim of this study was to assess coverage and parental acceptance of the HPV vaccine for adolescent daughters and sons in Brazil after its introduction into the NIP. In addition, the researchers sought to determine factors associated with parental intentions for female and male HPV vaccination.

Interviews were conducted by telephone from July 2015 to October 2016 in 7 Brazilian cities (Belém, Belo Horizonte, Brasília, Porto Alegre, Rio de Janeiro, São Paulo, and Salvador). A knowledge, attitude, and practices (KAP) questionnaire was developed and validated by expert analysis, semantic analysis, and pre-testing.

Among 826 parents who completed the interview, parental acceptance of the HPV vaccine for daughters and sons 18 years of age or less was high (92% and 86%, respectively). Knowing other parents who had their children vaccinated against HPV was associated with accepting HPV vaccination. Attitudes associated with HPV vaccine acceptance included: general belief in vaccines and trust in the NIP and in the HPV vaccine efficacy. (It has been shown that parents in countries with active vaccination policies tend to trust the importance of NIPs, while those in countries with passive vaccination strategies have a greater need for information from health care professionals and public health authorities.) Parents accepting HPV vaccine for daughters but not for sons were more likely to ignore the fact that the vaccine is recommended for boys.

Parents refusing vaccination were less likely to know that: HPV is sexually transmitted and causes genital warts, HPV vaccination is more beneficial before sexual debut, and HPV vaccine reactions are minor, and they were more likely to believe HPV vaccination can cause severe adverse events. (The researchers explain that, since parents' decision to vaccinate children was mainly based on their general belief in vaccines, acceptance rates may decline if parents are confronted by false arguments against vaccination from anti-vaccination narratives.)

Although most parents knew about HPV and its association with cervical cancer in women and other cancers in men, this knowledge was not associated with acceptance of HPV vaccination for daughters or sons. Relatively few parents in the study (10%) cited cancer prevention as one of the reasons to accept HPV vaccination, given that most (86%) knew about the link between HPV and cervical cancer. According to the researchers, it is possible that parents perceive cancers occurring later in life as less important on their decision to accept a vaccine given to pre-adolescents/adolescents.

Out of 291 parents with a daughter eligible to receive the HPV vaccine through the NIP (9 to 14 years of age), 170 (58.4%) reported their daughter had completed the 2-dose schedule, and 207 (71.1%) had received at least one dose. The most common reason reported for not having a daughter vaccinated or for not having them complete the regimen was "no vaccination/missed vaccination at school" (51.2% and 75.7% respectively).

Thus, the results show that parental acceptance of HPV vaccine in Brazil is high, as is trust of parents in the NIP and its recommended vaccines. Nevertheless, HPV vaccination coverage in the NIP remains low. Barriers to access to vaccination in health care settings are likely the main reason for low HPV vaccine uptake; therefore, changing back to a school-based vaccine delivery could improve vaccine coverage. Regardless of the vaccination strategies adopted, the researchers stress, more efforts should be made to educate parents and adolescents about HPV infection and its implications for male and female health. As for those refusing the vaccine, confidence in vaccines and perception of risk need to be addressed; for those who vaccinate daughters but not sons, stressing the purpose of vaccine as it pertains to males is important. "The modifiable factors identified here should be targeted in future interventions to increase HPV vaccine uptake among both males and females in Brazil."