VACCINES: DECISION MAKING, POLICY, AND CLINICAL TRIALS
* Finalists for the Lee B. Lusted Student Prize
Method: Following IRB approval, surveys were administered to parents of patients aged 9-26 who were seen at an academic urban pediatric practice. Surveys were offered in English or Spanish. Descriptive statistics and odds ratios were calculated. Fisher exact and Chi-square test were performed using VassarStats clinical calculator
Result: 193 surveys were evaluable. The median age of the reference patient was 14 (range 9-26) with 52% female and 48% male. Overall knowledge of the existence of the vaccine was high in this population with 81% of parents reporting prior knowledge of the vaccine. Private insurance status and higher annual household income were strongly associated with prior knowledge of the HPV vaccine (OR 12.1, 95% CI 3.6-41.5 and OR 10.3, 95% CI 2.4-45). 51% of parents reported that their child had been previously offered the HPV vaccine. There was no statistical difference in who was previously offered the vaccine by income, gender, insurance type, race or ethnicity. Interestingly, higher annual household income showed a trend towards association with not vaccinating the child with the HPV vaccine. Caucasian children were twice as likely to not be vaccinated against HPV (OR 2.1, 95% CI 1.03-4.08). Among all respondents, the most commonly cited reasons for not vaccinating their child was a belief that the child was not sexually active, lack of information regarding the vaccine, and fear of vaccine-related side effects.
Conclusion: Parents’ misperception of vaccine-associated risks coupled with their belief that their child is not at risk for HPV-related diseases likely contributes to low vaccine uptake in this population. Structured recommendation and education from health care providers regarding rationale for vaccine in the appropriate age group as well as vaccine safety may lead to increased acceptance and uptake of the vaccine against human papilloma virus.
Method: In November and December 2013 we conducted an online factorial experiment in which participants were randomized to receive information about influenza vaccines for children presented either in the standard format of the U.S. Centers for Disease Control and Prevention or in a best practices risk communication format. The latter used techniques such as presenting absolute risks in frequency format, using risk graphics, and explicitly presenting the incremental differences between the risks associated with each option. Participants were also randomized such that half of them received an interactive values clarification interface with dynamic visual feedback showing how their values related to the decision to vaccinate or not. We assessed all participants’ intentions to have their children vaccinated against influenza and the alignment between their intentions and values. To be eligible for the study, participants had to be parents/guardians in the US whose children were eligible for influenza immunization but had not yet received a vaccine in the current season.
Results: Participants (n=407) were a diverse sample of parents/guardians (mean age 35, SD 9, 63% female, 80% white, 47% no college degree) of children aged 6 months to 17 years. Participants randomized to the best practices risk communication format combined with the values clarification interface were most likely to indicate intentions to vaccinate (beta=2.08, p<.01). This effect was particularly notable among participants who had previously demonstrated less willingness to have their children vaccinated against influenza (beta=-2.14, p<.05). In addition, regardless of their intentions, participants receiving both interventions were the most likely to make choices that aligned with their values (Chi-squared(15)=32.1, p<0.01).
Conclusion: Good design for both risk communication and values clarification can improve decision quality by helping people to better understand the risks and benefits of options and to see how their values connect to their decisions.
Method: Forty in-depth, face-to-face interviews (20 in the US and 20 in the UK) were conducted with members of the public who represented a range of socio-demographic characteristics associated with vaccination uptake. To elicit previous experiences, underlying beliefs and perceptions influencing vaccination decisions, specifically seasonal flu and tetanus, we developed the journey to vaccination, a new qualitative approach anchored on the heuristics and biases tradition and the customer journey mapping approach. Journeys to vaccination for flu and tetanus were produced for each participant, and typical journeys were proposed. Thematic analysis was used to analyze the data.
Result: Regular flu vaccinators were more likely to trust their doctor, family and friends than intermittent and non-vaccinators. Non-vaccinators were more likely to have had a vaccine or health-related adverse psychological experience during childhood, whereas tetanus vaccinators recalled their mother’s warnings during childhood about tetanus’ severity. Perceived susceptibility to both flu and tetanus, and perceived severity of tetanus were key triggers to vaccination. These two factors formed an “emotional prism” through which the vaccines’ costs and benefits were assessed. Those who felt vulnerable to flu, for example, although still able to recognize the vaccine’s side-effects and partial efficacy, were more likely to receive the flu vaccine than those who did not feel vulnerable. Tetanus-containing boosters were more trusted than flu vaccines, mainly due to the changing composition of the latter.
Conclusion: Vaccination behavior should be viewed as a continuum, from childhood to adulthood, and not in isolation from each other or from other important health, or lifestyle-related events. Integrated interventions should be considered. Our findings suggest that fear is an important trigger of both vaccination acceptance and refusal and that vaccination decision-making often circumvents facts.
To estimate relative differences in influenza-assocaited hospitalizations and costs in the setting of a preferential policy for the use of live attenuated influenza vaccine (LAIV) in children compared with the current US vaccine policy.
The vaccine impact model published in 2013 by Kostova et al. was used to estimate relative benefits influenza vaccination programs based on two policies - the current recommendation (no preference for LAIV vs IIV) and a preferential recommendation to use LAIV vaccines among healthy children aged 2–8 years old. Given vaccination coverage estimates (44%, from National Health Interview Survey), vaccine efficacy (80% for LAIV and 44% for TIV), and hospitalization rate from FluSurv-NET, the model produces estimates on hospitalization cases in the presence and the absence of influenza vaccination. LAIV preferential recommendation would result in a situation of increased vaccination coverage rates for LAIV compared with IIV. Relative benefits are measured as comparisons of influenza-related hospitalization averted, defined as the difference between hospitalization cases with vaccination and without vaccination, under two different recommendations. Hospitalization costs averted were calculated from multiplying hospitalization averted by hospitalization costs per patient. Hospitalization costs were directly estimated from MarketScan database to reflect influenza-related hospitalization costs. We estimated the effects of the policy using data from the 2010-11 influenza season.
While the current recommendation (observed as 12% for LAIV and 32.6% for TIV) with no preference for LAIV prevented 2,825 hospitalizations compared with no vaccination, an LAIV preferential recommendation (assumed LAIV rate = 32.6% and TIV rate = 12%) in children would prevent 4,006 hospitalizations. Average hospitalization costs associated influenza were $7,174 for children who received LAIV vaccination and $8,506 for children who received TIV vaccination. An LAIV-preferred policy can prevent 1,181 (42%) more influenza-associated hospitalizations compared with the current policy. In terms of influenza-related hospitalizations, an LAIV preferential policy for children lead to reducing $30,070,746, while the current recommendation can reduce $23,016,806.
An LAIV preferential recommendation for children 2-8 years can produce more health benefits and cost-savings in terms of hospitalization averted.
Method: In 2011-2013, twenty primary care practices were randomly assigned to Year 1 Intervention and Year 2 Intervention arms of a randomized cluster trial to increase childhood influenza vaccination rates using a toolkit, early delivery of donated vaccine, educational in-service for staff, feedback on rates, and publicity. In Year 2, the intervention was conducted in the initial control (Year 2 Intervention) sites. Impact of the intervention in both arms and maintenance of intervention in the Year 1 intervention sites was assessed using t-tests, and multilevel regression modeling in this repeated measures study.
Result: For the Year 1 Intervention group, influenza vaccine uptake increased 12.4 percentage points (PP, P<0.01) during active intervention; uptake was sustained and during maintenance (0.4 PP change), for an overall change of 12.7 PP, increasing from 42.2% to 54.9% (P<0.001). Influenza vaccine uptake in the Year 2 intervention group increased in both Year 1 (5.2 PP; P<0.01) and in Year 2 (5.9 PP; P<0.01), for an overall change of 11.1 PP (P<0.001), increasing from 46.4% to 57.5%. Over the 2 years, among 82,395 children, vaccination increased in all practices and significantly (P<0.01) increased in 19 of 20 practices. Vaccination increased significantly regardless of race and insurance status, and among children over 2 years (P<0.001). In regression modeling that controlled for age, sex, race, and insurance, likelihood of vaccination was greater in Year 1 than baseline (odds ratio (OR) = 1.35 (95% confidence interval (CI)=1.33-1.38), in Year 2 than Year 1 (OR=1.13 (95%CI=1.11-1.15) and in Year 2 than baseline (OR=1.53 (95%CI=1.51-1.56; P<0.001 for each comparison).
Conclusion: In primary care practices, implementation of a multiple strategy intervention, which included practice improvement toolkit, early delivery of vaccine, feedback on rates and publicity, can significantly improve vaccination rates over two years among children across insurance and racial groups.