FormalPara Key Summary Points

Why carry out this study?

Invasive meningococcal disease (IMD) is a severe life-threatening disease which is vaccine preventable.

In the United States (US), vaccine coverage with separate MenACWY and MenB meningococcal vaccines is suboptimal among 16- to 23-year-olds, but a combined meningococcal vaccine (MenABCWY) could increase convenience (e.g., fewer injections) and improve coverage.

This study assessed preferences for hypothetical meningococcal vaccines among the current vaccine receivers (aged 16–23 years) and parents of 16- to 18-year-olds, to provide robust evidence for policymakers about patient preferences for the introduction of new meningococcal vaccines.

What was learned from the study?

Both US adolescents/young adults and parents expressed a significant preference for a hypothetical meningococcal vaccine which prioritized convenience, e.g., fewer doses and visits.

High trust in healthcare provider advice and Centers for Disease Control and Prevention recommendations influenced vaccination choice for both groups, while lack of awareness of meningococcal vaccines was a barrier, along with household income level and out-of-pocket costs for parents.

The preference for a convenient meningococcal vaccine (such as a combined MenABCWY vaccine) is important from a policy and public health perspective; a simplified vaccination schedule with a strong routine recommendation could help improve vaccine uptake, schedule compliance, disease prevention, and reduce inequalities in IMD risk and prevention.

Digital Features

This article is published with digital features, including a graphical abstract, to facilitate understanding of the article. To view digital features for this article, go to https://doi.org/10.6084/m9.figshare.26097385.

Introduction

Invasive meningococcal disease (IMD), caused by Neisseria meningitidis, is a severe, unpredictable, and life-threatening disease [1]. In the United States (US), the overall incidence was 0.09 per 100,000 population in 2022 [2], with disease trends showing a peak in incidence in young children (0.34) and in adolescents/young adults (0.15) [3]. In addition to its high case fatality rate (15.1% in 2021 [4]), IMD causes life-changing sequelae in up to 40% of survivors [5]. These can be physical, neurological, and psychological, such as limb amputations, hearing loss, visual disturbance, anxiety, and depression [5, 6]. In the US, in addition to age-related risks of IMD, certain socioeconomic groups were reported to be at increased risk of IMD, such as Medicaid versus commercially-insured populations [7], people experiencing homelessness [8], and college students [9], while a higher risk of mortality from IMD has been reported in poorer neighborhoods and some ethnic groups [10].

The majority of IMD cases worldwide are caused by six meningococcal serogroups (A, B, C, W, X, and Y) [11, 12]. In the US, serogroups B, C and Y are associated with most cases [3]. The Centers for Disease Control and Prevention (CDC) currently recommend routine vaccination with the serogroup A, C, W, and Y (MenACWY) vaccine for all 11- to 12-year-olds, with a booster dose at 16 years old [13]. The serogroup B (MenB) vaccine is recommended for 16- to 23-year-olds (preferably at age 16–18 years) under shared clinical decision-making (SCDM) [13]. Both MenACWY and MenB over 10 years of age, are routinely recommended for people at increased risk for IMD [14]. Since October 2023, the combined serogroup A, B, C, W, and Y (MenABCWY) vaccine may be used when both MenACWY and MenB are indicated at the same visit. This recommendation applies to healthy 16- to 23-year-olds (routine schedule) when SCDM favors administration of MenB vaccination, or 10-year-olds and older at increased risk of meningococcal disease (e.g., due to persistent complement deficiencies, complement inhibitor use, or functional or anatomic asplenia) due for both vaccines [13].

Although the CDC recommends meningococcal vaccination as the best way to prevent IMD, the uptake of the MenB vaccination is low (i.e., 29.4% coverage at age 17 years [15]) which could be partly due to the SCDM recommendation [16], while the uptake of the MenACWY booster dose is 60.8% at age 16 years [15]. The national ‘Healthy People 2020’ goals for immunization included increasing one-dose vaccination coverage to 80% for adolescents aged 13–15 years [17], while the current ‘Healthy People 2030’ goals include the objective of increasing coverage of recommended vaccines among individuals aged 19 years and older [18]. The introduction of a pentavalent (combined) MenABCWY vaccine with a simplified vaccine schedule and routine recommendation could help to improve vaccine coverage among adolescents/young adults. To date, no studies have quantified the preferences for a combined meningococcal vaccine among 16- to 23-year-olds, or among parents/caregivers (hereinafter, parents) of 16- to 18-year-olds. Understanding the preferences of these groups, and the barriers to accepting immunization, will be key to a successful implementation of a meningococcal immunization program [19, 20]. A common method to elicit patient preferences is through a discrete choice experiment (DCE). This method describes a hypothetical treatment or service according to its most relevant attributes (including different attribute levels), and determines the preference for each attribute [21].

The primary objective of this study was to quantify the preferences for hypothetical meningococcal vaccine profiles using a DCE, among adolescents/young adults and among parents of 16- to 18-year-olds in the US. Secondary objectives included quantifying the trade-offs for different vaccination attributes, assessing heterogeneity in preferences, and describing the importance of different attributes for subgroups.

Methods

Study Population

An online survey including a DCE was administered, between April and May 2023, to 16- to 23-year-olds (n = 300) and parents of 16- to 18-year-olds (n = 300) in the US.

Parents must have at least one 16- to 18-year-old for whom they had arranged at least 75% of visits to primary care providers in the preceding 3 years, and they must have attended at least 50% of visits with the 16- to 18-year-old. Both 16- to 23-year-olds and parents must be able to read and understand English to provide informed consent. Resource parents (i.e., foster or adoptive parents) were excluded.

Potential participants were identified via a participant recruitment database, SAGO, as well as healthcare provider (HCP) referrals, patient associations, and social media advertising (as needed) (see Supplemental file S1). All eligible participants were invited to complete an eligibility screener. Eligible participants who completed the screener and provided informed consent were directed to the online preference survey link. Eligible 16- and 17-year-olds provided their assent in addition to their parents’ consent. The survey was estimated to take approximately 40–50 min to complete.

Survey Design

Good research practice guidelines were applied to the DCE experimental design and the pilot [22, 23] and the analysis methods [24]. The DCE consisted of questions quantifying the relative importance that individuals place on vaccination features and estimated trade-offs. The survey also captured demographic characteristics, and information on meningococcal disease knowledge and vaccination.

Vaccination attributes and their associated attribute levels (Fig. 1) were determined following a targeted literature review [25] and interviews (focus groups) with 16- to 23-year-olds and parents [26]. Descriptions were provided for each attribute in lay terms (Table S1).

Fig. 1
figure 1

Attributes and attribute levels used in the DCE

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A pilot phase was conducted with 20 respondents from each group to confirm the feasibility of completing the survey. Learnings from the pilot were incorporated into the final survey. The pilot survey respondents were all included in the final survey samples.

DCE Methodology

A DCE was used to elicit and quantify relative preferences for attribute levels of treatments.

Trade-offs between hypothetical meningococcal vaccinations were presented independently to allow for estimation of the preference weights for each attribute level (i.e., trade-offs were uncorrelated). The trade-offs were evenly presented across respondents to avoid biasing the preference weight estimates (i.e., trade-offs needed to be balanced). Infeasible combinations of attribute levels were excluded, e.g., the number of injections could only be equal to or less than the number of visits to an HCP.

The experimental design implemented a commonly used D-optimal algorithm to construct a fractional factorial experimental design (statistically chosen subset of choice sets) [27]. This design maximizes information gathered about preferences by optimizing the number of discrete choice pairings required to compare all attribute levels.

To avoid presenting more choice tasks than respondents could feasibly answer, the experimental design was split into three blocks, each with ten trade-off combinations. Choices were not repeated across blocks. A block design was allocated to minimize selection bias, which could help minimize extreme views when choosing different choice options in the DCE task. Each respondent was randomly assigned to complete only one block in the DCE survey.

During the DCE, respondents were presented with an illustrative example of a pairwise choice set consisting of two hypothetical meningococcal vaccinations (Fig. 2). Respondents were presented with different pairwise choices including different combinations of attribute levels from five attributes. Respondents were then asked to choose their preferred vaccination profile (forced choice).

Fig. 2
figure 2

Example of a DCE choice task. DCE discrete choice experiment

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Statistical Methods

Summary descriptive statistics were used to describe the respondents invited to participate in the survey, participant characteristics, and responses to questions on meningococcal disease knowledge and vaccination experience.

For analysis of the primary data, the choice data were analyzed using a random parameter logit model to estimate preference parameters (see Supplemental file 2 for details). The responses to each pair of forced-choice trade-offs were modeled. Data were then analyzed to estimate predicted choice probabilities, i.e., the likelihood that an average respondent would select a specific vaccination profile. This approach allowed for preference weights for all attribute levels included in the survey to be estimated. A higher preference weight describes a more appealing attribute level, and the magnitude of difference between attribute levels represents the relative impact of changes in an attribute.

Subgroup Analysis

It was hypothesized a priori that factors such as out-of-pocket costs, lack of meningococcal vaccine awareness, or lack of trust in HCPs may reduce the preference for a meningococcal vaccine, while factors such as CDC recommendations or having an at-risk child may increase the preferences for a meningococcal vaccine. Subgroup analysis was used to determine whether average preferences varied among respondents in 13 mutually exclusive subgroups identified in post hoc analysis (e.g., by education level, household income, risk factors, awareness of meningococcal vaccines, or belief that vaccination interferes with natural protection; see full list in Tables S2 and S3). Preferences were explored to test for systematic differences in attribute preferences among 16- to 23-year-olds and parents (see Supplemental file 2 for details).

Ethics Compliance Statement

Institutional review board approval was received on 11/27/2022 from WCG IRB (IRB Tracking number 20226172). All survey respondents provided informed consent to participate in the study.

Results

Participant Characteristics

The survey was completed by 300 16- to 23-year-olds and 300 parents. Among the 16- to 23-year-olds, a third were 16- to 17-year-olds (n = 100) and two-thirds were 18–23-year-olds (n = 200). Their median age was 20 years (mean 20 years, standard deviation 2.5), approximately 53% were female, and 53% were White or Caucasian and 31% were Black or African American. Around 56% were either working full-time (34%) or part-time (22%), and around 35% were high school graduates. Most (53%) had a lower household income of less than US$75,000. Almost half of the respondents were from the Southern US (Table S4).

Among parents, their median age was 46 years (mean 47 years, standard deviation 8.2), approximately 45% were female, 44% were mothers, 53% were fathers, and approximately 3% were caregivers. Most were White or Caucasian (77%), and 14% were Black or African American. The majority (93%) were either working full-time (89%) or part-time (4%), and around 74% were graduates of a 2-year college or above or had some certificate, vocational or trade school education. Most (86%) had an upper household income of more than $75,000. Almost a third were from the Southern US (Table S4).

Quantifying Preferences for Hypothetical Meningococcal Vaccination Profiles

Overall, 89.6% of 16- to 23-year-olds and 69.1% of parents preferred a hypothetical meningococcal vaccination profile that was more simplified and could have added value, e.g., with fewer injections (3 vs. 4) and HCP visits (2–3 vs. 4) (Fig. 3; Table 1).

Fig. 3
figure 3

Preferences for hypothetical meningococcal vaccination profiles 1 and 2

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Table 1 Preference weights of 16- to 23-year-olds (n = 300) and parents (n = 300)
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Table 1 presents each group’s preference weights for attribute levels. Similar trends in relative attribute importance were observed for both 16- to 23-year-olds and parents, although the magnitude differed (Fig. S1). Dosing intervals (for both groups) and the number of injections (for parents) did not influence their preference for a meningococcal vaccine (Fig. S1).

Across the five attributes, preferences for attribute levels were ordered as expected, with better attribute levels being preferred to worse levels (Table 1).

Heterogeneity in Preferences Across Subgroups

Factors associated with heterogeneity in preferences for meningococcal vaccination varied among 16- to 23-year-olds and parents (Fig. 4).

Fig. 4
figure 4

Drivers and barriers associated with meningococcal vaccination preferences in 16- to 23-year-olds and parents. CDC Centers for Disease Control and Prevention, HCP healthcare provider, IMD invasive meningococcal disease

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For 16- to 23-year-olds, 81.5% (190/233) reported that having a CDC recommendation would have a positive impact on their decision about meningococcal vaccination. In addition, 16- to 23-year-olds’ beliefs around vaccination interference with natural protection were found to significantly impact preferences on meningococcal vaccination decision-making. Overall, 54.7% reported that they did not believe that vaccination interfered with natural protection (vs. 45.3% who did believe this) (Table S2).

For parents, four factors were significantly associated with meningococcal vaccination preferences: income (above or below $75,000), having a child with risk factors for meningococcal disease, having out-of-pocket costs, and beliefs around vaccination interference with natural protection. Overall, 85.7% had an income above $75,000. 70.1% (209/298) had an at-risk child, 51.3% reported that out-of-pocket costs impacted vaccine decision-making, and 68.3% believed that vaccination interfered with natural protection (Table S3).

Impact of Vaccine Recommendations on Meningococcal Vaccination Preferences and Decision-Making

Trust in vaccination information from HCPs was high among 16- to 23-year-olds (46.3% ‘absolutely trust’ and 37.0% ‘somewhat trust’) and among parents (72.0% ‘absolutely trust’ and 26.7% ‘somewhat trust’). Recommendations from the CDC were also highly impactful as 63.3% of 16- to 23-year-olds and 85.3% of parents stated that CDC recommendations would positively impact their decision to take a certain meningococcal vaccine. Having clear vaccine schedules and discussions with HCPs before agreeing to vaccination were important to both groups. Among 16- to 23-year-olds, 28.0% preferred a clear schedule, 35.3% preferred HCP discussions, and 32.3% preferred both options. Among parents, 51.3% preferred a clear schedule, 29.0% preferred HCP discussions, and 19.7% preferred both options (Fig. 4).

For 16- to 23-year-olds who had previously had a meningococcal vaccine, 35.7% had HCP advice, 20.8% were concerned about IMD or their health in general, 11.5% were influenced by family members or friends to get vaccinated, and 11.5% had a school requirement. The main reasons for not having a meningococcal vaccination were lack of awareness of meningococcal vaccines (28.0%), thinking they were too young for the vaccine (9.3%), and lack of HCP recommendation (7.6%). Among parents, concern for their child’s health (62.1%) and HCP recommendation (28.6%) were the primary reasons for having meningococcal vaccinations, while lack of awareness of meningococcal vaccines (17.7%) and lack of HCP recommendation (23.5%) were reasons for not having any (Fig. 4).

Discussion

Understanding patient values and preferences about new vaccinations is essential for public health decision-making aiming to optimize immunization programs, and for HCPs to successfully implement immunization. This study reported a preference for a simplified meningococcal vaccination among US adolescents/young adults aged 16–23 years and parents, including fewer injections and HCP visits, and less discomfort associated with injection administration. This preference aligns with the implementation of a combined MenABCWY vaccine versus separate MenACWY and MenB vaccines. Of note, subgroup analyses showed differences in parental preferences by socioeconomic factors, such as income level (e.g., in households with income less than versus more than $75,000) and out-of-pocket costs. These differences may contribute to suboptimal and inequitable uptake of vaccines, and should be considered by policymakers when implementing schedules or recommendations. HCP vaccination advice was reported to be important, and a large proportion of 16- to 23-year-olds (63%) and parents (85%) also stated that CDC recommendations significantly influenced their vaccination decisions. A lack of awareness of meningococcal vaccines and a lack of HCP advice were potential barriers to vaccination.

A recent preference study on meningococcal vaccination confirmed the positive influence of CDC or HCP recommendations on adolescent and parental vaccination decision-making, and found that participants preferred a combined versus separate meningococcal vaccine based on three vaccine attributes assessed (i.e., number of doses, efficacy/level of protection, and risk of adverse events) [28]. Previous studies in other disease areas reported that a reduced number of vaccinations and convenience are important drivers of adolescent and parental decisions [29, 30]. These findings align with the preference for convenience identified in this study, and suggest that simplifying the meningococcal vaccination schedule could improve coverage. For example, among vaccinees (including adults and adolescents), factors with a significant impact on vaccination decisions included dosing and visits, and information/advice/support from their HCP [29]. For parents, service delivery (e.g., location, availability of appointments) and type of administration (e.g., injections) were also important, in addition to cost and the number of doses and visits [29]. A study focusing on parental decision-making about their child’s vaccinations reported that switching to one- or two-dose regimens of human papillomavirus vaccine was expected to significantly increase adherence versus the three-dose regimen which had low vaccine completion rates (e.g., only one-third of girls completing the regimen) [30].

The study findings suggest that there are socioeconomic and other barriers to vaccination (e.g., differences due to household income level, out-of-pocket costs, a lack of awareness of vaccines, and not having HCP advice). These findings are also in line with previous surveillance of vaccine coverage in US adults. Among low-income households, a survey of Medicaid programs found that a minority (43%) covered all recommended vaccines, and that reimbursement costs to HCPs could be lower than the cost of vaccinating, which could limit HCP recommendations to some, and result in inequitable access to vaccination for low-income households [31]. While few adults ≥ 19 years reported receiving all of their recommended vaccinations, coverage rates were even lower in non-White racial/ethnic groups versus non-Hispanic White populations, and vaccination was higher in those with health insurance coverage and a usual place of healthcare [32]. The positive impact of provider recommendations on improving vaccine uptake has been reported previously, highlighting the value of providing simplified and strong recommendations for new vaccines. A recent review of meningococcal vaccination coverage in adolescents also identified HCP vaccine recommendations as a key factor to improve coverage and adherence in this age group [33]. A survey of parents and adolescents in the US found that low awareness and a lack of HCP advice about MenB vaccination were key barriers among the unvaccinated group, while the vaccinated group were largely unaware of the MenB SCDM recommendation but were influenced by HCP advice [34].

Acknowledging the decision-making vaccination drivers for adolescents and parents is important from a policy and public health perspective, especially when some vaccine decisions are expected to be made under SCDM (e.g., MenB vaccination). Since 2015, the CDC’s Advisory Committee on Immunization Practices recommended the MenB vaccine for 16- to 23-year-olds under SCDM. To date, MenB vaccination coverage remains suboptimal, with differences by racial and socioeconomic groups [35,36,37]. Research has shown that this recommendation is not well understood by HCPs, adolescents/young adults, and parents, which has an impact on both HCP vaccine recommendations (or lack thereof) to adolescents/young adults and parents, and the role of adolescents/young adults and parents in SCDM [14, 16, 34]. Low awareness and understanding of IMD, MenB vaccine recommendations, and SCDM among HCPs, adolescents/young adults, and parents also contributes to missed vaccination opportunities [34]. Parents also report wanting to vaccinate their child against IMD and wanting more vaccine information from their HCPs [34, 38]. Therefore, a simplified vaccine recommendation can be crucial in addressing the current knowledge gaps. A combined meningococcal vaccine with fewer doses and a strong HCP and CDC recommendation could help to alleviate the challenge of inequitable and suboptimal uptake of meningococcal vaccines, and, hence, help to reduce inequalities in risk and prevention.

When interpreting the results, it is important to consider the following limitations inherent in online survey designs: all data were self-reported, therefore confirmation of reported data such as vaccination status, and number of annual HCP visits was not validated, and the vaccination profiles were hypothetical and may not replicate the real-world vaccines or experiences of individuals receiving the meningococcal vaccinations where other considerations may come into play, such as access to care. The subgroup analyses were a post hoc analysis and, therefore, may not be adequately powered to estimate preference weights for each attribute level included in the study. Although the study used a large sample and efforts were made to obtain a geographically representative sample, the cohorts may not represent all parents or adolescents/young adults who receive or are eligible for meningococcal vaccinations in the US. For example, around 45% of the 16- to 23-year-olds reported receiving at least the one-dose MenB vaccine, which is higher than the US national rate of 29.4% reported in the NIS-Teen 2022 data [15].

Conclusions

The findings from this study provide information on adolescent/young adult and parent values and preferences to support public health policy decision-making on meningococcal vaccination in the US. Both 16- to 23-year-olds and parents prefer a simplified, more convenient, clear meningococcal vaccination schedule, with fewer doses and HCP visits, and less discomfort due to vaccination. Parent vaccination preferences differed by socioeconomic factors (household income and out-of-pocket costs), which may lead to inequalities in vaccine uptake. The introduction of a combined meningococcal (pentavalent MenABCWY) vaccine could help to improve vaccination uptake and compliance and disease prevention, and reduce inequalities in IMD risk and prevention.