Preferences for herpes zoster vaccination among adults aged 50 years and older in the United States: results from a discrete choice experiment

<b>Background:</b> Most adults, and disproportionately fewer African-Americans, have not received herpes zoster (HZ) vaccination despite current recommendations. This study (GSK study identifiers: 208677/HO-17-18066) assessed HZ vaccination preferences among adults aged ≥ 50 years. <b>Research design and methods:</b> In this discrete choice experiment, respondents chose among a ‘no vaccine’ option and two HZ vaccine profiles, characterized by seven attributes, in a series of choice questions. Random-parameters logit results were used to predict likely vaccine uptake. Subgroup and latent class analysis of African-American’s preferences were performed. <b>Results:</b> The preference weight for choosing HZ vaccines over no vaccine was statistically significant among the 1,454 respondents (71.9% whites; 25.2% African-Americans). Out-of-pocket (OOP) cost and vaccine effectiveness (VE) were the most important attributes. The African-American and the non-African-American subgroups had statistically significant differences in preferences (χ² = 59.91, p <b>Conclusions:</b> For all respondents, HZ vaccine choices were most sensitive to total OOP cost, followed by VE. PLAIN LANGUAGE SUMMARY Herpes zoster, or shingles, is a viral disease characterized by a painful, localized skin rash. It affects approximately 32% of US citizens at least once in their lifetime. The risk of contracting shingles increases with age. Most American adults over 50 years have not received the shingles vaccine, and vaccination rates are especially low for African-Americans. This is the first study to evaluate what drives shingles vaccination decisions among US adults ≥ 50 years of age. We also assessed the differences between African-American and non-African-American adults, and inside the African-American group. In this choice experiment, 1,454 people ≥ 50 years completed a survey of eight choice questions, as well as questions on their previous experiences with vaccines, socioeconomic, and demographic characteristics. Seven factors were evaluated. We found that American adults preferred to get vaccinated, and the most influential factors were costs and vaccine effectiveness while location of vaccination was the least important. There were differences in preferences between African-American and non-African-American adults, mainly driven by costs and vaccine effectiveness. Three different groups of African-American adults with systematically different preferences could be identified; two were likely to vaccinate, with one being more cost sensitive at lower price thresholds, and the third was unlikely to vaccinate. Decisions on shingles vaccination appear to be mostly driven by costs, which could be a barrier to those who do not have appropriate insurance, especially among some African-Americans. However, healthcare professionals should continue to educate patients on other vaccine characteristics, as they also influence vaccination decisions.