Factors Affecting Vaccine Hesitancy among Families with Children 2 Years Old and Younger in Two Urban Communities in Manila, Philippines

"...there was a significant positive association between exposure to negative media information about vaccines and vaccine hesitancy among the study population."

In November 2017, a media frenzy erupted in the Philippines. One year after a mass vaccination campaign with the Dengvaxia® vaccine, which reached around 800,000 schoolchildren, the vaccine's manufacturer revealed that the vaccine potentially increased the risk of severe dengue in children. The controversy that arose has been cited as one of the probable reasons for the loss of vaccine confidence in the Philippines, which in turn contributed to an 8-fold increase in the incidence rate of measles from late 2017 to 2018. In this context, the objective of this study was to determine the factors associated with vaccine hesitancy in the Philippines, with the hope of potentially informing interventions to bolster vaccination rates.

As the researchers explain, the Strategic Advisory Group of Experts (SAGE) technical working group has accepted 2 working models regarding the determinants of vaccine hesitancy: the 3Cs model, composed of complacency, convenience, and confidence, and the Working Group Matrix, which categorises the determinants of vaccine hesitancy into 3 major groups: contextual influences (arising due to historic, sociocultural, environmental, health system/institutional, economic, or political factors); individual and group influences (arising from personal perception of the vaccine or influences of the social/peer environment); and vaccine/vaccination-specific issues (directly related to vaccines or vaccination).

The study used a cross-sectional study design with a modified questionnaire adapted from the SAGE Working Group on Vaccine Hesitancy. A total of 119 parents and caregivers of children 2 years old and younger in 2 urban barangays (smallest administrative divisions) in Manila, Philippines completed the self-administered survey; only 110 responses, submitted mostly by 20- to 39-year-old mothers, were included in the final data due to incomplete survey or informed consent information.

Most respondents (95.5%) believed that vaccines are protective, and many (84.6%) believed that most parents have their children vaccinated with recommended vaccines. Respondents who believed in the protective nature of vaccines were less likely to report vaccine hesitancy and were 9 times less likely to refuse vaccination for their children because of negative media exposure. A large majority (95.0%) agreed that community leaders support child vaccination. Healthcare workers and political leaders were identified as top vaccination advocates (76.8% and 68.7%, respectively), followed by teachers and religious leaders (23.2% and 18.2%, respectively).

However, 36.4% of the respondents either hesitated or refused to give at least one vaccination to their children. Respondents who hesitated to have their children receive at least one vaccination were also 16.7 times more likely to have refused least one vaccination for their children. Almost 11% of respondents believed there could be reasons why children should not be vaccinated; 41.7% of them believed they can choose not to vaccinate. The primary reason for vaccine refusal was negative information from the media (69.2%), followed by concerns about the safety of vaccines (46.2%).

The results of this study suggest vaccine hesitancy is an issue for parents and caregivers of children 2 years old and younger in Manila, regardless of age, gender, educational attainment, religion, income bracket, or relationship to the children. The findings suggest that the well-publicised events surrounding the Dengvaxia® controversy contributed to a decrease in vaccine confidence. The role of mass media in vaccine hesitancy was highlighted in this study, supporting previous evidence that vaccine-hesitant parents tend to be more susceptible to media reports.

In conclusion, the researchers suggest that vaccine hesitancy might be addressed by a multi-stakeholder approach in the community, as the role of political and religious community leaders in supporting vaccination strategies appears to be evident. In addition, the role of health workers needs to be re-emphasised and strengthened; they were the most commonly cited advocates for vaccination in this study. "Empowering and mobilizing health workers to take an active role in promoting accurate and timely information on the benefits of immunization and allaying the community's fears and distrust of vaccines is still the most important strategy."