We performed a systematic literature review in PubMed and Embase (2016–2021) to investigate the drivers of and barriers to routine vaccination in adults aged 50 and older globally. A thematic assessment identified three categories across 61 publications: sociodemographic, health-related, and attitudinal. The most common sociodemographic determinants (factors identified in studies; n = 47) associated with vaccination uptake were economic status, age, education, and household composition, which had mixed effects on vaccine uptake. For health-related determinants (n = 27), individuals with comorbidities and health care consumption were the most common factors, both increased vaccine uptake. The most common attitudinal factors (n = 42) were self-efficacy, provider or other’s recommendations, and vaccine-preventable disease awareness; across studies, all attitude factors had a positive effect, unlike the sociodemographic and health status categories. Findings suggest that patient and provider awareness and education campaigns are effective ways to increase uptake of routine vaccinations in older adults.

Policies and programs to increase vaccine coverage rates among adults 50 years of age or older are limited and vaccine uptake is often suboptimal. Our review evaluated evidence on the effectiveness and success of adult-targeted vaccination interventions and identified literature gaps. Literature was retrieved (2021) from PubMed, Embase, and Google Scholar databases. Outcomes assessed included data on an intervention’s effectiveness and impact on vaccine uptake. Interventions were characterized thematically: affordability (n = 9), awareness (n = 25), and vaccination access (n = 6); and included influenza, pneumococcal, tetanus-containing, and herpes zoster vaccines. Interactive interventions directed toward patients, including provider-led educational initiatives and provider recommendations showed more positive associations than less interactive interventions, such as posters and reminder-recall letters. Provider interventions, including awareness campaigns, incentives, affordability efforts, or vaccination site expansion generally showed positive associations. Combining interventions was found to be successful across several studies. Barriers and interventions varied for population subgroups, therefore, tailoring programs is critical.

Despite vaccines being instrumental in reducing vaccine-preventable disease, adult vaccination rates in the United States (US) are below optimal levels. To better understand factors affecting vaccination rates, we analyzed trends in adult vaccination coverage using data from the Behavioral Risk Factor Surveillance System (BRFSS) and conducted a targeted literature review (TLR) on interventions to improve adult vaccination rates in the US. Both the BRFSS analysis and the TLR focused on influenza; pneumococcal disease; tetanus and diphtheria or tetanus, diphtheria, and acellular pertussis; herpes zoster; and human papillomavirus vaccination for US adults aged 18-64 years. The TLR additionally included hepatitis A and hepatitis B vaccination. Vaccination coverage rates (VCRs) and changes in VCRs were calculated using the 2011-2019 BRFSS survey data. For the TLR, the MEDLINE and MEDLINE In-Process databases were searched for articles on vaccination interventions published between January 2015 and June 2021. The BRFSS analysis showed that changes in VCRs were generally modest and positive for most states over the study period. The TLR included 32 articles that met the eligibility criteria; intervention strategies that improved adult vaccination outcomes incorporated an educational component, vaccination reminders or reinforcement at the point of care, or authorized non-clinician members of the healthcare team to vaccinate. Furthermore, interventions combining more than one approach appeared to enhance effectiveness. The strategies identified in this TLR will be valuable for policymakers and stakeholders to inform the development and implementation of evidence-based policies and practices to improve adult vaccination coverage.

Healthcare providers' (HCPs') beliefs and practices regarding vaccination influence vaccine acceptance in patients. To describe HCPs' beliefs and practices regarding vaccines and perceptions of patient perspectives related to vaccine hesitancy. This was a non-interventional, cross-sectional, online survey administered to 1213 HCPs based in the United States from December 2021 through January 2022. HCPs provided responses regarding their demographic and professional characteristics, beliefs about vaccine safety and effectiveness, vaccination practices, and their views regarding patients' willingness to receive vaccination. Study participants included doctors (55.4 %); physician assistants (11.2 %); pharmacists (11.7 %); nurse practitioners (11.1 %); and registered nurses (10.6 %) from across the United States (West, 35.6 %; Midwest, 27.0 %; South, 25.6 %; Northeast, 11.9 %). HCPs belonged to group practices or clinics (34.5 %), private practices (31.9 %), hospital-based practices (21.9 %), or pharmacies (11.7 %). Most HCPs strongly believed it was their duty to promote vaccination (78.1 %) and used in-person conversations to educate patients about vaccines (85.0 %); 95.1 % had been vaccinated against COVID-19. HCPs reported that 54.9 % of patients accept all vaccines without hesitation, 21.0 % accept all vaccines but hesitate, 16.8 % accept only select vaccines, and 7.2 % reject all vaccines. Reasons commonly cited by patients for being hesitant to accept vaccines or refusal included negative media (hesitancy: 64.6 %; refusal: 73.2 %), the influence of friends or family (hesitancy: 60.5 %; refusal: 68.7 %), distrust of the government (hesitancy: 45.8 %; refusal: 68.4 %), concerns over long-term side effects (hesitancy: 56.1 %; refusal: 68.3 %), and worries about vaccine-related autism or infertility (hesitancy: 49.7 %; refusal: 71.9 %). HCPs reported that the largest contributors to vaccine misinformation among patients were social media (91.0 %), celebrities/TV personalities (63.5 %), and mass media (61.1 %). Despite most HCPs being active proponents of vaccination, misconceptions about vaccination and vaccine hesitancy persists. Consideration should be given to HCP training to support their efforts to promote vaccine acceptance.

Background: Vaccine literacy (knowledge about vaccines and the ability to identify accurate information about them) and vaccine hesitancy (delay in or refusal of vaccination) among parents may affect immunization decision-making and pediatric vaccine uptake. This study aimed to examine the demographic and socioeconomic characteristics of parents by vaccine literacy and hesitancy and to assess the relationship between attitudinal, behavioral, and experiential factors and parents’ vaccine literacy and hesitancy. Methods: A cross-sectional survey was administered in 2022 to US adults aged ≥ 18 (N = 692) who self-identified as parents/guardians of children aged < 18. Parents were asked questions about their experiences assessing information on pediatric vaccinations, their information-seeking and decision-making practices, interactions with healthcare providers (HCPs) regarding pediatric vaccines, beliefs about vaccine efficacy and safety, trust in scientific and medical information from various sources, perceptions of the danger and severity of vaccine-preventable diseases, and the benefits and convenience of vaccination. High vaccine literacy was defined as being moderately or extremely familiar with the vaccines a child should receive. Vaccine hesitancy was defined as being somewhat or very hesitant, or not sure, about childhood immunizations (i.e., shots). An exploratory factor analysis reflected 7 discrete underlying variables describing self-reported behaviors, beliefs, and experiences regarding childhood vaccination. Results: Vaccine literacy and hesitancy were associated with parents’ gender, race/ethnicity, education level, and urbanicity. Factors associated with increased vaccine literacy were positive interactions with HCPs (OR 2.24, P < 0.001), active information-seeking behavior (OR 1.88, P < 0.001), positive beliefs about vaccines (OR 1.39, P = 0.001), and beliefs about vaccination requirements (OR 1.21, P = 0.041). Trouble understanding information from HCPs was associated with decreased vaccine literacy (OR 0.80, P = 0.025). Factors associated with decreased vaccine hesitancy were positive beliefs about vaccines (OR 0.41, P < 0.001), minimal concerns over childhood vaccines (OR 0.46, P < 0.001), and positive interactions with HCPs (OR 0.76, P = 0.002). Increased hesitancy was associated with negative beliefs about vaccines (OR 3.26, P < 0.001) and trouble understanding information from HCPs (OR 1.44, P < 0.001). Conclusions: Greater vaccine literacy levels and less vaccine hesitancy correlated with positive parental beliefs about vaccines and positive interactions with HCPs. Challenges in comprehending HCP-delivered information were correlated with lower literacy and greater hesitancy.

Background: Vaccines serve as a crucial public health tool, although vaccine hesitancy continues to pose a significant threat to full vaccine uptake and, consequently, community health. Understanding and tracking vaccine hesitancy is essential for effective public health interventions; however, traditional survey methods present various limitations. Objective: This study aimed to create a real-time, natural language processing (NLP)–based tool to assess vaccine sentiment and hesitancy across 3 prominent social media platforms. Methods: We mined and curated discussions in English from Twitter (subsequently rebranded as X), Reddit, and YouTube social media platforms posted between January 1, 2011, and October 31, 2021, concerning human papillomavirus; measles, mumps, and rubella; and unspecified vaccines. We tested multiple NLP algorithms to classify vaccine sentiment into positive, neutral, or negative and to classify vaccine hesitancy using the World Health Organization’s (WHO) 3Cs (confidence, complacency, and convenience) hesitancy model, conceptualizing an online dashboard to illustrate and contextualize trends. Results: We compiled over 86 million discussions. Our top-performing NLP models displayed accuracies ranging from 0.51 to 0.78 for sentiment classification and from 0.69 to 0.91 for hesitancy classification. Explorative analysis on our platform highlighted variations in online activity about vaccine sentiment and hesitancy, suggesting unique patterns for different vaccines. Conclusions: Our innovative system performs real-time analysis of sentiment and hesitancy on 3 vaccine topics across major social networks, providing crucial trend insights to assist campaigns aimed at enhancing vaccine uptake and public health.