Safety, tolerability, and immunogenicity of an adult pneumococcal conjugate vaccine, V116 (STRIDE-3): a randomised, double-blind, active comparator controlled, international phase 3 trial.

BACKGROUND: The same pneumococcal conjugate vaccines (PCVs) have been used in adults and children in many settings. Differences in the epidemiology of pneumococcal disease between populations necessitates an adult-specific PCV. We aimed to assess the safety, tolerability, and immunogenicity of V116, an investigational 21-valent PCV designed for adults. METHODS: This randomised, double-blind, active comparator controlled, international phase 3 trial enrolled adults with or without stable chronic medical conditions at 112 clinical sites in 11 countries or territories. Random assignment was performed using a central electronic interactive response technology system. Cohort 1 (≥50 years) was stratified by age (50-64, 65-74, 75-84, and ≥85 years) and randomised 1:1 to receive one intramuscular dose of V116, or the active comparator, PCV20. Cohort 2 (18-49 years) was randomised 2:1 to receive one intramuscular dose of V116 or PCV20. Pneumococcal serotype-specific opsonophagocytic activity (OPA) and IgG responses were measured before (day 1) and after vaccination (day 30). Four primary immunogenicity outcomes were assessed per-protocol. First, in cohort 1, non-inferiority of V116 to PCV20 was tested using serotype-specific OPA geometric mean titres (GMT) ratios for serotypes common to both vaccines; the lower bound of the 95% CI had to be greater than 0·5 for non-inferiority. Second, superiority of V116 to PCV20 was tested for OPA GMT ratios for the serotypes unique to V116; the lower bound of the 95% CI had to be greater than 2·0 for superiority. Third, superiority of V116 to PCV20 was evaluated by the proportions of participants with a four-fold or greater rise from day 1 to day 30 for serotypes unique to V116; the lower bound of the 95% CI of the differences in proportions (V116 - PCV20) had to be greater than 10% for superiority. Finally, in cohort 2, immunobridging was assessed for all 21 serotypes in V116 for adults aged 18-49 years to 50-64 years; the lower bound of the 95% CI for the OPA GMTs had to be greater than 0·5 for non-inferiority. The safety analysis included all randomly assigned participants who received study vaccine. The primary safety outcome was the proportion of participants with solicited injection site and solicited systemic adverse events until day 5 and vaccine-related serious adverse events up to 6 months after vaccination. This trial is registered at ClinicalTrials.gov (NCT05425732). FINDINGS: Between July 13, and Nov 22, 2022, 2754 individuals were screened and 2663 participants were randomly assigned. 2656 individuals were vaccinated (1179 in V116 cohort 1; 1177 in PCV20 cohort 1; 200 in V116 cohort 2; and 100 in PCV20 cohort 2). V116 met non-inferiority criteria compared with PCV20 for the ten serotypes common to both vaccines at day 30 in cohort 1 (p<0·0001 for each common serotype). V116 met superiority criteria compared with PCV20 in cohort 1 for ten of the 11 serotypes unique to V116 at day 30 (OPA GMT ratio: p<0·0001 for all unique serotypes except 15C, which was p=0·41; four-fold or greater rise in OPA from day 1-30: p<0·0001 for all serotypes except 15C, which was p=0·67). Immune responses in V116 participants aged 18-49 years were non-inferior compared with V116 participants aged 50-64 years for all V116 serotypes (p<0·0001 for all V116 serotypes). In cohort 1, 685 (58·2%) of participants in V116, and 778 (66·2%) of participants in PCV20 reported one or more adverse event. In cohort 2, 164 (82·0%) participants in V116 and 79 participants (79·0%) in PCV20 reported one or more adverse event. Six deaths were reported, all in cohort 1, none of which were considered vaccine-related (in V116: one due to sepsis, one due to cerebrovascular accident, one due to myocardial infarction, and one due to hepatic cirrhosis and hepatic encephalopathy; in PCV20: one due to cardiac arrest and one due to abdominal abscess). There were no vaccine-related serious adverse events. INTERPRETATION: V116 was non-inferior to PCV20 for the ten serotypes common to both vaccines and superior to PCV20 for all serotypes unique to V116, except for 15C. Immune responses successfully immunobridged between younger and older adults for all serotypes in V116. V116 was generally well tolerated with safety profile similar to PCV20. FUNDING: Merck Sharp & Dohme, subsidiary of Merck & Co, Rahway, NJ, USA (MSD).

The role of Zambia's expansive Inter-agency Coordinating Committee (ICC) in supporting evidence-based vaccine and health sector programming.

New vaccines, technologies, and regulations, alongside increased demand for vaccines, all require prioritization and coordination from key players within the vaccine sector. Inter-agency Coordinating Committees (ICC) support decision-making and coordination at the national-level and act as key drivers for sustainable improvements in vaccination programming. We utilized a previous qualitative case study, which investigated critical success factors for high routine immunization coverage in Zambia from 2000-2018, specifically to study the Zambian ICC. Qualitative data were collected between October 2019 and February 2020, including key informant interviews (n = 66) at the national, provincial, district, and health facility levels. Thematic analysis was applied to understand the role of the Zambian ICC and its impact on the policy environment over time. Within our study period, the ICC demonstrated the following improvements: 1) expanded membership to include diverse representation; 2) expanded scope and mandate to include maternal and child health in decision-making; and 3) distinct roles for collaboration with the Zambia Immunization Technical Advisory Group (ZITAG). The diverse and expansive membership of the Zambian ICC, along with its ability to foster government commitment and lobby for additional resources, supported improvements in immunization programming. The Zambian ICC holds considerable influence on government agencies and external partners, which facilitates procurement of funding, policy decisions, and strategic planning.

Development and validation of VaxConcerns: A taxonomy of vaccine concerns and misinformation with Crowdsource-Viability.

We present VaxConcerns, a taxonomy for vaccine concerns and misinformation. VaxConcerns is an easy-to-teach taxonomy of concerns and misinformation commonly found among online anti-vaccination media and is evaluated to produce high-quality data annotations among crowdsource workers, opening the potential adoption of the framework far beyond just academic or medical communities. The taxonomy shows high agreement among experts and outperforms existing taxonomies for vaccine concerns and misinformation when presented to non-expert users. Our proof-of-concept study on the changes in anti-vaccination content during the COVID-19 pandemic indicate impactful future use cases, such as longitudinal studies of the shift in vaccine concerns over time.

A mixed integer programming model for vaccine pricing within a group purchasing organization.

BACKGROUND: Setting prices for life-saving medical or pharmaceutical products needs to consider multiple factors, e.g., affordability and health outcomes across different populations. When a group of buyers (e.g., countries) combine their purchasing power (e.g., via a group purchasing organization), the average procurement price decreases in the total volume. Decisions about what price to then charge to each member in a group are particularly challenging, considering the disparities in their respective ability and willingness to pay. Tiered pricing can be an effective way to set prices for a group of buyers, but its performance needs to be quantified and evaluated. METHODS: We modeled the decision of setting prices of a medical product (for example, a vaccine) for a group of buyers using a mixed integer programming model, considering the buyers' ability and willingness to pay. The objective is to minimize the unit price disparity adjusted by the buyers' willingness to pay, subject to the constraint that the prices decrease in the buyers' ability to pay. We also developed an analogous subsidy allocation model that applies if the group receives philanthropic donations to support procurement. The models were illustrated with two case studies based on the Bacillus Calmette-Guerin (BCG) vaccine procurement by Gavi, the Vaccine Alliance and Pan American Health Organization, and the performances of uniform, tiered, and differentiated pricing schemes were examined. RESULTS: The adjusted unit price disparity is non-increasing in the number of price tiers allowed. The biggest decrease in the adjusted price disparity occurs when switching to two-tier pricing from uniform pricing. Tiered pricing performs better in the Gavi group compared to the PAHO group, in part because the ability to pay and willingness to pay have a higher degree of rank correlation within the former group of countries. CONCLUSIONS: This work provides a model for price-setting (subsidy allocation) decisions for a group of buyers and provides a quantitative comparison of different pricing schemes. The results of the case studies suggest that the performance of tiered pricing depends on various factors, including the disparities in the ability and willingness to pay across the buyers. FUNDING: This research has been supported in part by the Center for Health and Humanitarian Systems, the William W. George endowment, and the following benefactors at Georgia Tech: Andrea Laliberte, Richard Rick E. and Charlene Zalesky, and Claudia and Paul Raines.

Corrigendum: LetsTalkShots: personalized vaccine risk communication.

[This corrects the article DOI: 10.3389/fpubh.2023.1195751.].

Evaluation of online videos to engage viewers and support decision-making for COVID-19 vaccination: how narratives and race/ethnicity enhance viewer experiences.

Background: Vaccine hesitancy has hampered the control of COVID-19 and other vaccine-preventable diseases. Methods: We conducted a national internet-based, quasi-experimental study to evaluate COVID-19 vaccine informational videos. Participants received an informational animated video paired with the randomized assignment of (1) a credible source (differing race/ethnicity) and (2) sequencing of a personal narrative before or after the video addressing their primary vaccine concern. We examined viewing time and asked video evaluation questions to those who viewed the full video. Results: Among 14,235 participants, 2,422 (17.0%) viewed the full video. Those who viewed a personal story first (concern video second) were 10 times more likely to view the full video (p < 0.01). Respondent-provider race/ethnicity congruence was associated with increased odds of viewing the full video (aOR: 1.89, p < 0.01). Most viewers rated the informational video(s) to be helpful, easy to understand, trustworthy, and likely to impact others' vaccine decisions, with differences by demographics and also vaccine intentions and concerns. Conclusion: Using peer-delivered, personal narrative, and/or racially congruent credible sources to introduce and deliver vaccine safety information may improve the openness of vaccine message recipients to messages and engagement.

LetsTalkShots: personalized vaccine risk communication.

Introduction: Vaccine hesitancy is a global health threat undermining control of many vaccine-preventable diseases. Patient-level education has largely been ineffective in reducing vaccine concerns and increasing vaccine uptake. We built and evaluated a personalized vaccine risk communication website called LetsTalkShots in English, Spanish and French (Canadian) for vaccines across the lifespan. LetsTalkShots tailors lived experiences, credible sources and informational animations to disseminate the right message from the right messenger to the right person, applying a broad range of behavioral theories. Methods: We used mixed-methods research to test our animation and some aspects of credible sources and personal narratives. We conducted 67 discussion groups (n = 325 persons), stratified by race/ethnicity (African American, Hispanic, and White people) and population (e.g., parents, pregnant women, adolescents, younger adults, and older adults). Using a large Ipsos survey among English-speaking respondents (n = 2,272), we tested animations aligned with vaccine concerns and specific to population (e.g., parents of children, parents of adolescents, younger adults, older adults). Results: Discussion groups provided robust feedback specific to each animation as well as areas for improvements across animations. Most respondents indicated that the information presented was interesting (85.5%), clear (96.0%), helpful (87.0%), and trustworthy (82.2%). Discussion: Tailored vaccine risk communication can assist decision makers as they consider vaccination for themselves, their families, and their communities. LetsTalkShots presents a model for personalized communication in other areas of medicine and public health.

Critical interventions for demand generation in Zambia, Nepal, and Senegal with regards to the 5C psychological antecedents of vaccination.

Introduction: Childhood vaccination is an effective intervention for lowering the burden of infectious disease. Vaccine coverage has increased globally, but vaccine hesitancy and refusal threatens these gains. The 5C psychological antecedents of vaccination ("5C") provides a validated measure of "vaccine hesitancy or confidence" to assess individual thoughts and behaviors behind vaccination. We investigated population-level factors that contributed to high and sustained vaccination coverage in Zambia, Nepal, and Senegal, and alignment with the 5Cs. Methods: Data was collected in the larger Exemplars in Vaccine Delivery study, from focus group discussions (FDGs) and key informant interviews (KIIs) at the national, regional, district, health facility, and community levels of health systems in Zambia, Nepal, and Senegal. We assessed the demand environment, as relayed by participants, and identified interventions reported as successful for demand generation, then retroactively aligned the interventions with the 5C constructs. Results: Demand was positively correlated with high confidence and collective responsibility. Psychological constraints sometimes impacted demand. Physical constraints created barriers in some communities, particularly difficult to access (i.e., mountainous). Occasionally, physical constraints did not affect vaccination behavior - parents believed the benefits of vaccination worth pursuing. Factors negatively correlated with demand and intent, complacency and calculation, had limited impact. Critical interventions were: targeted and tailored health education activities (media partnerships, school outreach); community engagement; community ownership; and community involvement (community health workers, leaders, religious figures). Conclusion: We found similar interventions used to generate demand, with strategies aligned with the 5C constructs. Categorizing interventions by drivers of demand may help strategic planning and the division of resources; decision makers may choose to implement our suggested interventions. Assessing the 5Cs allows decision-makers to operationalize demand generation into concrete interventions and policies, and determine the individual impact of these constructs on the population and focus efforts on interventions tailored to a specific need.

Empowering Health Workers to Build Public Trust in Vaccination: Experience from the International Pediatric Association's Online Vaccine Trust Course, 2020-2021.

BACKGROUND: The quality of interactions between health workers (HWs) and caregivers is key in vaccine acceptance. To optimize this, HWs need knowledge about best vaccine communication practices in person and on social media. Most pre-service curricula do not include such approaches. COVID-19 necessitated the International Pediatric Association (IPA) to shift from in-person train the trainer workshops to developing an online Vaccine Trust Course to address these gaps. METHOD: The seven-module, 8-hour Vaccine Trust Course was offered online in seven languages and promoted globally. Course outcomes for participants between September 1, 2020 and September 30, 2021 were assessed using enrollment, participation, and completion data; pre-and post-training surveys of attitudes, knowledge, and practice skills; and follow-up practice surveys 3 months post course completion. RESULTS: Of the 4,926 participants across 137 countries who registered; 2,381 (48.3 %) started the course, with 1,217 (51.1 %) completing. The majority were 25 - 39 years (57 %), female (57 %), and in pediatrics (70 %); 31 % came from India. 62 % of completers rated course structure/design as excellent, 36 % as good. Over 80 % rated the content as the most valuable aspect. Three months post training, 61 % HWs reported increased empathy towards caregivers, confidence while counseling and increased vaccine acceptance amongst their patients. 21 % identified the course as the only factor in these positive changes. CONCLUSION: Shifting from face-to-face to online training due to the COVID-19 pandemic helped increase the global reach of HWs course engagement and uptake. Trained HWs reported increased empathy towards caregivers and confidence while counseling and increased patient vaccine acceptance.

MomsTalkShots, tailored educational app, improves vaccine attitudes: a randomized controlled trial.

BACKGROUND: Many pregnant women and parents have concerns about vaccines. This analysis examined the impact of MomsTalkShots, an individually tailored educational application, on vaccine attitudes of pregnant women and mothers. METHODS: MomsTalkShots was the patient-level component of a multi-level intervention to improve maternal and infant vaccine uptake that also included provider- and practice-level interventions. The impact of these interventions was studied using a two-by-two factorial design, randomizing at both the patient- and the practice-level. Study staff recruited pregnant women from a diverse set of prenatal care practices in Colorado and Georgia between June 2017 and July 2018. All participants (n = 2087) received a baseline survey of maternal and infant vaccine intentions and attitudes, and two follow-up surveys at least 1 month and 1 year after their infant's birth, respectively. Half of participants (n = 1041) were randomly assigned to receive educational videos through MomsTalkShots, algorithmically tailored to their vaccine intentions, attitudes, and demographics. Since the practice/provider intervention did not appear impactful, this analysis focused on MomsTalkShots regardless of the practice/provider intervention. RESULTS: By 1 month post-birth, MomsTalkShots increased perceived risk of maternal influenza disease (61% among MomsTalkShots recipients vs 55% among controls; Odds Ratio: 1.61, 95% Confidence Interval: 1.23-2.09), confidence in influenza vaccine efficacy (73% vs 63%; OR: 1.97, 95%CI: 1.47-2.65), and perceived vaccine knowledge (55% vs 48%; OR: 1.39, 95%CI: 1.13-1.72). Among those intending not to vaccinate at baseline, MomsTalkShots increased perceived risk of maternal influenza disease (38% vs 32%; OR: 2.07, 95%CI: 1.15-3.71) and confidence in influenza vaccine efficacy (44% vs 28%; OR: 2.62, 95%CI: 1.46-4.69). By 1 year post-birth, MomsTalkShots increased perceived vaccine knowledge (62% vs 50%; OR: 1.74, 95%CI: 1.36-2.24) and trust in vaccine information from obstetricians and pediatricians (64% vs 55%; OR: 1.53, 95%CI: 1.17-2.00). Among those uncertain about vaccinating at baseline, MomsTalkShots increased perceived vaccine knowledge (47% vs 12%; OR: 6.89, 95%CI: 1.52-31.25) and reduced infant vaccine safety concerns (71% vs 91%; OR: 0.24, 95%CI: 0.06-0.98). CONCLUSIONS: MomsTalkShots improved pregnant women's and mothers' knowledge and perceptions of maternal and infant vaccines and the diseases they prevent, and offers a scalable tool to address vaccine hesitancy. TRIAL REGISTRATION: Registered at Clinicaltrials.gov on 13/09/2016 (registration number: NCT02898688).

Impact of vaccine pause due to Thrombosis with thrombocytopenia syndrome (TTS) following vaccination with the Ad26.COV2.S vaccine manufactured by Janssen/Johnson & Johnson on vaccine hesitancy and acceptance among the unvaccinated population.

BACKGROUND: In response to reports of thrombosis with thrombocytopenia syndrome (TTS) post-vaccination, the Johnson & Johnson (J&J) vaccine was paused and then restarted in April 2021. Our objective was to assess whether this pause adversely impacted vaccine confidence. METHODS: Two large internet-based surveys were conducted in the US among adults to measure knowledge, attitudes and perceptions of the J&J vaccine pause and rates of vaccine hesitancy among unvaccinated persons before, during and after the pause. RESULTS: Among 66% of respondents aware of the pause, 44% identified blood clots as the reason for the pause without prompting. The impact of the pause on vaccine behavior among unvaccinated persons and perception of the vaccine safety system was mixed and modified by trust in the public health authorities. Those who were less willing to get vaccinated because of the pause were less inclined for all vaccines, not only the J&J product. Moreover, a notable proportion (22.1%) of the small number of persons (n = 30) vaccinated with the J&J vaccine after the pause reported not receiving information about the risk of TTS. The proportion of unvaccinated persons who were hesitant was increasing before and during the pause and then leveled off after the pause. CONCLUSIONS: The J&J vaccine pause is unlikely to be a major barrier to vaccine uptake. Public attitudes about vaccines may be more resilient than appreciated, especially when safety issues are investigated with transparent communication. This paper has important implications for messaging and program administration with future vaccine-specific adverse events. Efforts may be warranted to ensure all persons being offered the J&J vaccine are made aware of the risk of TTS.

Multi-tiered intervention to increase maternal immunization coverage: A randomized, controlled trial.

OBJECTIVE: To evaluate the impact of a multi-component intervention package of maternal immunization uptake in obstetric care clinics. METHODS: In a multi-level, cluster- and individually-randomized controlled trial we implemented an evidence-based intervention that targeted practice-, provider- and patient-level barriers to vaccine uptake. Obstetric practices were randomized to receive the practice and provider-level interventions or continue their normal standard of care. We enrolled pregnant women at practices in Georgia and Colorado and randomized women into patient-level intervention and control groups, resulting in four study arms. The primary outcomes were receipt of the influenza and tetanus, diphtheria and acellular pertussis (Tdap) vaccines during pregnancy. A sample size of 550 women per arm (2200 total) was planned and enrolled to compare the intervention between the four study arms. RESULTS: Between June 2017 and July 2018, 4907 women were screened and 2200 women were randomized, 550 to each of the four study arms. We were unable to follow-up with 108 women, for a final sample size of 2092. Sample characteristics and sample size were similar among study arms. There was no significant increase in Tdap or influenza vaccine uptake overall. Among women who had no intention of or were unsure about receiving the influenza vaccine during pregnancy, those who received just the patient-level intervention were 61% more likely to receive the influenza vaccine than those in the control arm (Relative risk: 1.61; 95% Confidence Interval: 1.18-2.21). There was no significant difference in vaccine uptake for either influenza or tetanus, diphtheria and acellular pertussis between the four arms of the study. CONCLUSIONS: This trial highlights the need for more targeted interventions to improve vaccine uptake. Future work should focus on clinics with low baseline vaccine uptake and the patient-level intervention should be expanded and targeted towards women with low vaccine confidence.

Use of Random Domain Intercept Technology to Track COVID-19 Vaccination Rates in Real Time Across the United States: Survey Study.

BACKGROUND: Accurate and timely COVID-19 vaccination coverage data are vital for informing targeted, effective messaging and outreach and identifying barriers to equitable health service access. However, gathering vaccination rate data is challenging, and efforts often result in information that is either limited in scope (eg, limited to administrative data) or delayed (impeding the ability to rapidly respond). The evaluation of innovative technologies and approaches that can assist in addressing these limitations globally are needed. OBJECTIVE: The objective of this survey study was to assess the validity of Random Domain Intercept Technology (RDIT; RIWI Corp) for tracking self-reported vaccination rates in real time at the US national and state levels. RDIT-a form of online intercept sampling-has the potential to address the limitations of current vaccination tracking systems by allowing for the measurement of additional data (eg, attitudinal data) and real-time, rapid data collection anywhere there is web access. METHODS: We used RDIT from June 30 to July 26, 2021, to reach a broad sample of US adult (aged ≥18 years) web users and asked questions related to COVID-19 vaccination. Self-reported vaccination status was used as the focus of this validation exercise. National- and state-level RDIT-based vaccination rates were compared to Centers for Disease Control and Prevention (CDC)-reported national and state vaccination rates. Johns Hopkins University's and Emory University's institutional review boards designated this project as public health practice to inform message development (not human subjects research). RESULTS: By using RDIT, 63,853 adult web users reported their vaccination status (6.2% of the entire 1,026,850 American web-using population that was exposed to the survey). At the national level, the RDIT-based estimate of adult COVID-19 vaccine coverage was slightly higher (44,524/63,853, 69.7%; 95% CI 69.4%-70.1%) than the CDC-reported estimate (67.9%) on July 15, 2021 (ie, midway through data collection; t63,852=10.06; P<.001). The RDIT-based and CDC-reported state-level estimates were strongly and positively correlated (r=0.90; P<.001). RDIT-based estimates were within 5 percentage points of the CDC's estimates for 29 states. CONCLUSIONS: This broad-reaching, real-time data stream may provide unique advantages for tracking the use of a range of vaccines and for the timely evaluation of vaccination interventions. Moreover, RDIT could be harnessed to rapidly assess demographic, attitudinal, and behavioral constructs that are not available in administrative data, which could allow for deeper insights into the real-time predictors of vaccine uptake-enabling targeted and timely interventions.

Assessing vaccine effectiveness against severe COVID-19 disease caused by omicron variant. Report from a meeting of the World Health Organization.

Vaccine effectiveness is lower and wanes faster against infection and symptomatic disease caused by the omicron variant of SARS-CoV-2 than was observed with previous variants. Vaccine effectiveness against severe omicron disease, on average, is higher, but has shown variability, including rapid apparent waning, in some studies. Assessing vaccine effectiveness against omicron severe disease using hospital admission as a measure of severe disease has become more challenging because of omicron's attenuated intrinsic severity and its high prevalence of infection. Many hospital admissions likely occur among people with incidental omicron infection or among those with infection-induced exacerbation of chronic medical conditions. To address this challenge, the World Health Organization held a virtual meeting on March 15, 2022, to review evidence from several studies that assessed Covid-19 vaccine effectiveness against severe omicron disease using several outcome definitions. Data was shown from studies in South Africa, the United States, the United Kingdom and Qatar. Several approaches were proposed that better characterize vaccine protection against severe Covid-19 disease caused by the omicron variant than using hospitalization of omicron-infected persons to define severe disease. Using more specific definitions for severe respiratory Covid-19 disease, such as indicators of respiratory distress (e.g. oxygen requirement, mechanical ventilation, and ICU admission), showed higher vaccine effectiveness than against hospital admission. Second, vaccine effectiveness against progression from omicron infection to hospitalization, or severe disease, also showed higher vaccine protection. These approaches might better characterize vaccine performance against severe Covid-19 disease caused by omicron, as well as future variants that evade humoral immunity, than using hospitalization with omicron infection as an indicator of severe disease.

Masks, money, and mandates: A national survey on efforts to increase COVID-19 vaccination intentions in the United States.

Various efforts to increase COVID-19 vaccination rates have been employed in the United States. We sought to rapidly investigate public reactions to these efforts to increase vaccination, including self-reported responses to widespread reduced masking behavior, monetary incentive programs to get vaccinated, and work vaccination requirements. Using a unique method for data collection (Random Domain Intercept Technology), we captured a large (N = 14,152), broad-based sample of the United States Web-using population (data collected from June 30 -July 26, 2021). About 3/4 of respondents reported being vaccinated. The likelihood of vaccination and vaccination intention differed across various demographic indicators (e.g., gender, age, income, political leaning). We observed mixed reactions to efforts aimed at increasing vaccination rates among unvaccinated respondents. While some reported that specific efforts would increase their likelihood of getting vaccinated (between 16% and 32%), others reported that efforts would decrease their likelihood of getting vaccinated (between 17% and 42%). Reactions differed by general vaccination intention, as well as other demographic indicators (e.g., race, education). Our results highlight the need to fully understand reactions to policy changes, programs, and mandates before they are communicated to the public and employed. Moreover, the results emphasize the importance of understanding how reactions differ across groups, as this information can assist in targeting intervention efforts and minimizing potentially differential negative impact.

In Elimination Settings, Measles Antibodies Wane After Vaccination but Not After Infection: A Systematic Review and Meta-Analysis.

BACKGROUND: We conducted a systematic review to assess whether measles humoral immunity wanes in previously infected or vaccinated populations in measles elimination settings. METHODS: After screening 16 822 citations, we identified 9 articles from populations exposed to wild-type measles and 16 articles from vaccinated populations that met our inclusion criteria. RESULTS: Using linear regression, we found that geometric mean titers (GMTs) decreased significantly in individuals who received 2 doses of measles-containing vaccine (MCV) by 121.8 mIU/mL (95% confidence interval [CI], -212.4 to -31.1) per year since vaccination over 1 to 5 years, 53.7 mIU/mL (95% CI, -95.3 to -12.2) 5 to 10 years, 33.2 mIU/mL (95% CI, -62.6 to -3.9), 10 to 15 years, and 24.1 mIU/mL (95% CI, -51.5 to 3.3) 15 to 20 years since vaccination. Decreases in GMT over time were not significant after 1 dose of MCV or after infection. Decreases in the proportion of seropositive individuals over time were not significant after 1 or 2 doses of MCV or after infection. CONCLUSIONS: Measles antibody waning in vaccinated populations should be considered in planning for measles elimination.