An Assessment of Parents' Childhood Immunization Beliefs, Intentions, and Behaviors Using a Smartphone Panel

"...smartphone data collection can provide a relatively fast and lower-cost approach for identifying potential indicators or correlates of parental vaccination acceptance and compliance (e.g., the underlying beliefs that may be associated with increased delays or refusals)."

Knowing parents' beliefs and intentions regarding recommended childhood immunisations can help immunisation programmes and healthcare providers address vaccination concerns and identify emerging issues. However, the United States (US) Centers for Disease Control and Prevention (CDC)'s National Immunization Survey (NIS) does not involve regular assessment of parent beliefs or intentions regarding recommended immunisations. In the US and elsewhere, the pervasive reach and use of smartphones (e.g., penetration exceeds 90% in the 18-49-year-old age cohort) opens a potential pathway to collect valid and reliable data in a rapid, cost-efficient way. The present study used this data collection strategy to assess: (i) parental immunisation-related beliefs, intentions, and behaviours; (ii) the relationships between beliefs and intentions regarding child immunisation and actual behaviours (i.e., refusals or delays in recommended vaccinations); and (iii) whether beliefs, intentions, and/or behaviours varied across various demographic subgroups.

The survey was implemented between December 16 and 21 2017 via the Surveys On The Go® mobile research app for Android or iOS smartphones. Those individuals who download the app (not vaccine-specific), agree to the terms of service, and create an account become members of an all-mobile consumer panel. For the study, 1,029 parents, ages 18 and older, with a child 19 to 35 months answered questions about immunisation behaviour, intention, and belief questions using the smartphone app. (For purposes of comparability to the NIS, only the 1,001 respondents who indicated they were the most knowledgeable adult in the household were included in the analyses.) The survey instrument replicated many survey questions as well as sequencing from the NIS, yet it included other measures, such as those drawn from the 6 behavioural items in the Parental Attitudes and Childhood Vaccines (PACV) survey tool.

Ninety-six percent of respondents reported that all their children aged 19 to 35 months had received all recommended vaccines. However, 22.1% said they had delayed having their child/children getting a recommended vaccine for reasons other than illness or allergy. Moreover, 3.5% of all parents indicated they had decided not to have their child/children get a recommended vaccine. In addition, while seasonal flu vaccination is on the childhood vaccination schedule, only 65% of parents reported that their children aged 19 to 35 months had received a flu vaccine during the past year. The demographic factors most closely associated with immunisation behaviours were respondents' education level and self-reported household income.

Nine of 10 parents agreed that childhood vaccines were effective (92%); that having their child vaccinated was important for the health of others in their community (93%); and that childhood vaccines were important for their child's health (95%). While 75% agreed that the information they received about vaccines from the government was reliable and trustworthy, two-thirds of delaying parents held this belief, and only 43.3% of declining parents indicated agreement.

Looking in more depth at vaccine hesitancy issues: Nearly half agreed that children get too many vaccines during the first 3 years of life (45%) and that some vaccines were given to children to prevent diseases that they are unlikely to get (46%). In addition, approximately one-third of parents believed that some vaccines are given to children to prevent diseases that are not serious (33%) and that some vaccines have ingredients that are unsafe (35%). A smaller portion believed that some vaccines may cause learning disabilities such as autism (19%). Notably, 48.7% of delaying parents and 58.1% of declining parents indicated some level of agreement with the statement that vaccines may cause learning disabilities, including autism.

According to the researchers, these findings could provide insights into the knowledge deficits and beliefs that may be hindering parents' compliance with the recommended childhood immunisation schedule. The results suggest that immunisation programmes and providers need to be prepared to address questions and concerns related to vaccine ingredients, the timing of recommended vaccinations, and the potential harms posed by all vaccine-preventable diseases (VPDs). In addition, the associations found between demographic characteristics and belief measures suggest that immunisation programmes and providers should be mindful that parents with less formal education or household income may have questions or doubts about the safety of vaccines and the importance of all recommended childhood vaccines.

The researchers point out that this survey was conducted in a few days and at lower cost than traditional methods. While the approach does not enable calculation of confidence intervals around survey responses, they say that "it can provide immunization programs and providers with the means to do relatively rapid assessments of parents' beliefs and intentions regarding vaccines and/or the recommended childhood immunization schedule."

In conclusion, this study could serve as a model for health agencies where rapid results or inexpensive approaches are needed. Findings could be used by public health agencies and immunisation providers to inform their vaccination education and communication efforts and to guide decisions regarding additions to traditional probability-based survey research methods.