Self-reported Vaccination Research Articles

Can delay discounting predict vaccine hesitancy 4-years later? A study among US young adults

Despite being a major threat to health, vaccine hesitancy (i.e., refusal or reluctance to vaccinate despite vaccine availability) is on the rise. Using a longitudinal cohort of young adults (N = 1260) from Los Angeles County, California we investigated the neurobehavioral mechanisms underlying COVID-19 vaccine hesitancy. Data were collected at two time points: during adolescence (12th grade; fall 2016; average age = 16.96 (±0.42)) and during young adulthood (spring 2021; average age = 21.33 (±0.49)). Main outcomes and measures were delay discounting (DD; fall 2016) and tendency to act rashly when experiencing positive and negative emotions (UPPS-P; fall 2016); self-reported vaccine hesitancy and vaccine beliefs/knowledge (spring 2021). A principal components analysis determined four COVID-19 vaccine beliefs/knowledge themes: Collective Responsibility, Confidence and Risk Calculation, Complacency, and Convenience. Significant relationships were found between themes, COVID-19 vaccine hesitancy, and DD. Collective Responsibility (β = -1.158[-1.213,-1.102]) and Convenience (β = -0.132[-0.185,-0.078]) scores were negatively associated, while Confidence and Risk Calculation (β = 0.283[0.230,0.337]) and Complacency (β = 0.412[0.358,0.466]) scores were positively associated with COVID-19 vaccine hesitancy. Additionally, Collective Responsibility (β = -0.060[-0.101,-0.018]) was negatively associated, and Complacency (β = -0.063[0.021,0.105]) was positively associated with DD from fall 2016. Mediation analysis revealed immediacy bias during adolescence, measured by DD, predicted vaccine hesitancy 4 years later while being mediated by two types of vaccine beliefs/knowledge: Collective Responsibility (β = 0.069[0.022,0.116]) and Complacency (β = 0.026[0.008,0.044]). These findings provide a further understanding of individual vaccine-related decision-making among young adults and inform public health messaging to increase vaccination acceptance.

Effect of an Innovative Immunization Practice Model to Improve Population Health: Results of the Project IMPACT Immunizations Scaled Demonstration.

Background: U.S. adult vaccination rates remain low. Community pharmacists have skills and opportunity to improve this shortcoming. This study sought to evaluate an innovative practice model on identification of unmet vaccination needs and their resolution. Methods: This prospective, multi-site, multi-state, observational study was conducted in 22 community pharmacy practices in Iowa and Washington. Adults receiving influenza vaccination, medication therapy review, prescriptions for diabetes or cardiovascular disease, or another clinical encounter with a participating pharmacist from December 2017 through November 2019 were included. Pharmacists reviewed vaccination forecasts generated by clinical decision support technology based on their state immunization information system (IIS) to identify unmet vaccination needs, educate patients, and improve vaccination rates. The primary outcomes were numbers of vaccination forecast reviews, patients educated, unmet vaccination needs identified and resolved, and vaccinations administered. Secondary outcomes included numbers of vaccination declinations; times a forecasted vaccine was not recommended because a contraindication was identified by the pharmacist; and times the patients declined a forecasted vaccine due to self-reported vaccination despite lack of documentation in the state IIS. Descriptive statistics were calculated. Results: Pharmacists reviewed vaccination forecasts for 6,234 patients. The vaccination forecasts predicted there were 11,789 vaccinations needed (1.9 per person). 6,405 of the 11,789 unmet vaccination needs (54.3%) were fulfilled during the study period, including 60% on the same day. Of the forecasted needs, 1,085 (9.2%) were found to be previously administered and 59 (0.5%) contraindicated. The remaining patients received information about their personal vaccination needs and recommendations to be vaccinated. Conclusion: Availability of vaccination histories during patient encounters allowed pharmacists to identify and resolve adult vaccination needs in independent and chain community practice settings.

How do psychobehavioural variables shed light on heterogeneity in COVID-19 vaccine acceptance? Evidence from United States general population surveys on a probability panel and social media

ObjectivesTo (1) understand what behaviours, beliefs, demographics and structural factors predict US adults’ intention to get a COVID-19 vaccination, (2) identify segments of the population (‘personas’) who share similar factors...

Association between community-level political affiliation and peripartum vaccination

Political affiliation has been associated with vaccine uptake, but whether this association holds in pregnancy, when individuals are recommended to receive multiple vaccinations, remains to be studied. This study aimed to examine the association between community-level political affiliation and vaccinations for tetanus, diphtheria, and pertussis; influenza; and COVID-19 in pregnant and postpartum individuals. A survey was conducted about tetanus, diphtheria, and pertussis and influenza vaccinations in early 2021, with a follow-up survey of COVID-19 vaccination among the same individuals at a tertiary care academic medical center in the Midwest. Geocoded residential addresses were linked at the census tract to the Environmental Systems Research Institute 2021 Market Potential Index, which ranks a community in comparison to the US national average. The exposure for this analysis was community-level political affiliation, defined by the Market Potential Index as very conservative, somewhat conservative, centrist, somewhat liberal, and very liberal (reference). The outcomes were self-reported vaccinations for tetanus, diphtheria, and pertussis; influenza; and COVID-19 in the peripartum period. Modified Poisson regression was used and adjusted for age, employment, trimester at assessment, and medical comorbidities. Of 438 assessed individuals, 37% lived in a community characterized by very liberal political affiliation, 11% as somewhat liberal, 18% as centrist, 12% as somewhat conservative, and 21% as very conservative. Overall, 72% and 58% of individuals reported receiving tetanus, diphtheria, and pertussis and influenza vaccinations, respectively. Of the 279 individuals who responded to the follow-up survey, 53% reported receiving COVID-19 vaccination. Individuals living in a community characterized by very conservative political affiliation were less likely to report vaccinations for tetanus, diphtheria, and pertussis (64% vs 72%; adjusted risk ratio, 0.83; 95% confidence interval, 0.69-0.99); influenza (49% vs 58%; adjusted risk ratio, 0.79; 95% confidence interval, 0.62-1.00); and COVID-19 (35% vs 53%; adjusted risk ratio, 0.65; 95% confidence interval, 0.44-0.96) than those in a community characterized by very liberal political affiliation. Individuals living in a community characterized by centrist political affiliation were less likely to report vaccinations for tetanus, diphtheria, and pertussis (63% vs 72%; adjusted risk ratio, 0.82; 95% confidence interval, 0.68-0.99) and influenza (44% vs 58%; adjusted risk ratio, 0.70; 95% confidence interval, 0.54-0.92) than those in a community characterized by very liberal political affiliation. Compared with pregnant and postpartum individuals living in communities characterized by very liberal political beliefs, those living in communities characterized by very conservative political beliefs were less likely to report vaccinations for tetanus, diphtheria, and pertussis; influenza; and COVID-19, and those in communities characterized by centrist political beliefs were less likely to report vaccinations for tetanus, diphtheria, and pertussis and influenza. Increasing vaccine uptake in the peripartum period may need to consider engaging an individual's broader sociopolitical milieu.

Intrauterine Insemination (IUI) Pregnancy Rates After COVID-19 Vaccination [ID: 1376042

INTRODUCTION: Public concern over the potential negative effect of COVID-19 vaccines on fertility has persisted, as confidence in COVID-19 vaccines remains low, especially in certain Midwestern populations. We evaluated the success of intrauterine inseminations (IUIs) in achieving pregnancy in women who self-report receiving at least one dose of the vaccine against SARS-CoV-2, compared with women who self-report declining the vaccine. METHODS: This is a retrospective cohort study of 109 IUI procedures in women receiving fertility treatment at the University of Missouri Reproductive Endocrinology and Infertility clinic from October 2021 through September 2022. Participants were grouped based on self-reported COVID-19 vaccination status, prior to their IUI. The primary outcome was pregnancy after IUI, as verified by a serum pregnancy test. This study was performed under University of Missouri IRB approval (IRB #MU2062683). RESULTS: In comparing women self-reporting COVID-19 vaccination versus nonvaccination, no statistical differences were found for positive serum pregnancy tests after IUI (17.3% among vaccinated; 21.7% among nonvaccinated). Although these IUI success rates are higher than the national average, there was no significant difference in pregnancy rates (P=.6331). CONCLUSION: In this limited sample, self-reported COVID-19 vaccination status does not appear to have a significant negative effect on the ability to conceive a pregnancy with IUI. Further prospective studies should evaluate the effect of male partner or sperm donor vaccination, the number and type of COVID-19 vaccines received, pregnancy outcomes, and confounders. This study may help address the ongoing questions of whether the COVID-19 vaccines have a significant negative effect on fertility and pregnancy outcomes.

Predictors and barriers to vaccination among older Syrian refugees in Lebanon: a cross-sectional analysis of a multi-wave longitudinal study

Vaccination is important to prevent morbidity and mortality due to COVID-19 among older Syrian refugees. We aimed to elucidate the predictors of COVID-19 vaccine uptake among Syrian refugees aged 50 years or older in Lebanon and to understand their main reasons for not receiving the vaccine. This was a cross-sectional analysis of a five-wave longitudinal study, conducted through telephone interviews between Sept 22, 2020, and March 14, 2022, in Lebanon. For this analysis, data were extracted from wave 3 (Jan 21-April 23, 2021), which included a question on vaccine safety and on whether participants intended to receive the COVID-19 vaccine, and wave 5 (Jan 14-March 14, 2022), which included questions on actual vaccine uptake. Syrian refugees aged 50 years or older were invited to participate from a list of households that received assistance from the Norwegian Refugee Council, a humanitarian non-governmental organisation. The outcome was self-reported COVID-19 vaccination status. Multivariable logistic regression was used to identify predictors of vaccination uptake. Validation was completed internally with bootstrapping methods. 2906 participants completed both wave 3 and 5; the median age was 58 (IQR 55-64) years and 1538 (52·9%) were male. 1235 (42·5%) of 2906 participants had received at least one dose of the COVID-19 vaccine. The main reasons for not receiving the first dose included being afraid of its side-effects (670 [40·1%] of 1671) or not wanting the vaccine (637 [38·1%] of 1671). 806 (27·7%) of 2906 participants received the second dose of the vaccine and 26 (0·9%) of 2906 received the third dose. The main reason for not receiving the second (288 [67·1%] of 429) or third dose (573 [73·5%] of 780) was waiting for a text message for an appointment. Predictors of receiving at least one dose of the COVID-19 vaccine included younger age (odds ratio 0·97; 95% CI 0·96-0·98), being male (1·39; 1·19-1·62), living inside informal tented settlements (1·44; 1·24-1·66), having elementary (1·23; 1·03-1·48) and preparatory education or above (1·15; 0·95-1·40), and having a pre-existing intention to receive the vaccine (1·29; 1·10-1·50). After adjusting for optimisation, the final model, which includes these five predictors of receiving at least one dose of the COVID-19 vaccine, showed moderate discrimination (C-statistic 0·605; 95% CI 0·584-0·624) and good calibration (c-slope 0·912; 95% CI 0·758-1·079). There is an ongoing need to address COVID-19 vaccine uptake among older Syrian refugees by improving deployment planning and raising awareness about the importance of vaccination. ELRHA's Research for Health in Humanitarian Crisis Programme.

Factors associated with COVID-19 vaccination during June-October 2021: A multi-site prospective study.

Vaccine hesitancy presents a challenge to COVID-19 control efforts. To identify beliefs associated with delayed vaccine uptake, we developed and implemented a vaccine hesitancy survey for the COVID-19 Community Research Partnership. In June 2021, we assessed attitudes and beliefs associated with COVID-19 vaccination using an online survey. Self-reported vaccination data were requested daily through October 2021. We compared responses between vaccinated and unvaccinated respondents using absolute standardized mean differences (ASMD). We assessed validity and reliability using exploratory factor analysis and identified latent factors associated with a subset of survey items. Cox proportional hazards models and mediation analyses assessed predictors of subsequent vaccination among those initially unvaccinated. In June 2021, 29,522 vaccinated and 1,272 unvaccinated participants completed surveys. Among those unvaccinated in June 2021, 559 (43.9%) became vaccinated by October 31, 2021. In June, unvaccinated participants were less likely to feel "very concerned" about getting COVID-19 than vaccinated participants (10.6% vs. 43.3%, ASMD 0.792). Among those initially unvaccinated, greater intent to become vaccinated was associated with getting vaccinated and shorter time to vaccination. However, even among participants who reported no intention to become vaccinated, 28.5% reported vaccination before study end. Two latent factors predicted subsequent vaccination-being 'more receptive' was derived from motivation to protect one's own or others' health and resume usual activities; being 'less receptive' was derived from concerns about COVID-19 vaccines. In a Cox model, both factors were partially mediated by vaccination intention. This study characterizes vaccine hesitant individuals and identifies predictors of eventual COVID-19 vaccination through October 31, 2021. Even individuals with no intention to be vaccinated can shift to vaccine uptake. Our data suggest factors of perceived severity of COVID-19 disease, vaccine safety, and trust in the vaccine development process are predictive of vaccination and may be important opportunities for ongoing interventions.

Trends in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and vaccine antibody prevalence in a multi-ethnic inner-city antenatal population: A cross-sectional surveillance study.

To determine severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in pregnancy in an inner-city setting and assess associations with demographic factors and vaccination timing. Repeated cross-sectional surveillance study. London maternity centre. A total of 906 pregnant women attending nuchal scans, July 2020-January 2022. Blood samples were tested for IgG antibodies against SARS-CoV-2 nucleocapsid (N) and spike (S) proteins. Self-reported vaccination status and coronavirus disease 2019 (COVID-19) infection were recorded. Multivariable regression models determined demographic factors associated with seroprevalence and antibody titres. Immunoglobulin G N- and S-protein antibody titres. Of the 960 women, 196 (20.4%) were SARS-CoV-2 seropositive from previous infection. Of these, 70 (35.7%) self-reported previous infection. Among unvaccinated women, women of black ethnic backgrounds were most likely to be SARS-CoV-2 seropositive (versus white adjusted risk ratio [aRR] 1.88, 95% CI 1.35-2.61, p < 0.001). Women from black and mixed ethnic backgrounds were least likely to have a history of vaccination with seropositivity to S-protein (versus white aRR 0.58, 95% CI 0.40-0.84, p = 0.004; aRR 0.56, 95% CI 0.34-0.92, p = 0.021, respectively). Double vaccinated, previously infected women had higher IgG S-protein antibody titres than unvaccinated, previously infected women (mean difference 4.76 fold-change, 95% CI 2.65-6.86, p < 0.001). Vaccination timing before versus during pregnancy did not affect IgG S-antibody titres (mean difference -0.28 fold-change, 95% CI -2.61 to 2.04, p = 0.785). This cross-sectional study demonstrates high rates of asymptomatic SARS-CoV-2 infection with women of black ethnic backgrounds having higher infection risk and lower vaccine uptake. SARS-CoV-2 antibody titres were highest among double-vaccinated, infected women.

Attitude and influencing factors to receive the COVID-19 vaccine among university students in Sichuan Province, China: A cross-sectional study.

To explore the university students' attitude and the potential influencing factors to receive the coronavirus disease 2019 (COVID-19) vaccine in Sichuan Province, China. A cross-sectional study. The self-designed questionnaire was distributed among university students online in June 2021. SPSS software was used for statistical analysis of the data. Descriptive statistics, Chi-square, two independent samples t-tests, one-way analysis of variance (ANOVA), multivariate linear regression, and content analysis were performed. A total of 397 questionnaires were analysed, involving 316 (79.6%) respondents have received at least one dose of a COVID-19 vaccine and 81 (20.4%) have not taken the vaccine. The total mean score of university students' vaccination attitude was 25.97 (standard deviation [SD] = 3.720), and the total scoring rate was 74.2%. Main factors influencing students' attitude included education level, major, living style, with chronic disease or not, self-reported vaccination status, and number of medical units that can provide vaccination within 3 km of residence. Students were more willing to choose Chinese-manufactured vaccines (66.8%) and participate in collective vaccination programs organized by the school (71.3%). The desired vaccine protection period was 5-10 years (42.1%). The top three reasons for refusing the vaccine or vaccine hesitancy were as follows: concern about the side effects of vaccine (44.8%), lack of information about vaccine (31.0%), and concern about the efficacy of vaccine (29.3%). In general, most of the participants had relatively high level of positive attitude to receive the COVID-19 vaccine. Nevertheless, more attention should be paid to postgraduate students, non-medical students, those living alone, those with chronic disease, those have not received the COVID-19 vaccine, and those living far away from the vaccination medical units. Findings of this study can help educational institutions in developing effective interventions to improve the vaccination rate in the university student population.

Factors Associated With Coronavirus Disease 2019 Vaccine Uptake Among Pregnant Women and Nonpregnant Women of Reproductive Age in Jamaica.

Despite high rates of coronavirus disease 2019 (COVID-19)-related maternal mortality, Jamaica currently has little data on COVID-19 vaccine uptake among pregnant women. We conducted a cross-sectional, web-based survey of 192 reproductive-aged women in Jamaica from February 1 to 8, 2022. Participants were recruited from a convenience sample of patients, providers, and staff at a teaching hospital. We assessed self-reported COVID-19 vaccination status and COVID-19-related medical mistrust (operationalized as vaccine confidence, government mistrust, and race-based mistrust). We used multivariable modified Poisson regression to test the association between vaccine uptake and pregnancy. Of 192 respondents, 72 (38%) were pregnant. Most (93%) were Black. Vaccine uptake was 35% in pregnant women versus 75% in nonpregnant women. Pregnant women were more likely to cite healthcare providers versus the government as trustworthy sources of COVID-19 vaccine information (65% vs 28%). Pregnancy, low vaccine confidence, and government mistrust were associated with a lower likelihood of COVID-19 vaccination (adjusted prevalence ratio [aPR] = 0.68 [95% confidence interval {CI}, .49-.95], aPR = 0.61 [95% CI, .40-.95], and aPR = 0.68 [95% CI, .52-.89], respectively). Race-based mistrust was not associated with COVID-19 vaccination in the final model. Pregnancy, low vaccine confidence, and government mistrust were associated with a lower likelihood of COVID-19 vaccination among reproductive-aged women in Jamaica. Future studies should evaluate the efficacy of strategies proven to improve maternal vaccination coverage, including standing "opt-out" vaccination orders and collaborative provider and patient-led educational videos tailored for pregnant individuals. Strategies that decouple vaccine messaging from government agencies also warrant evaluation.

Validation of the Vaccination Trust Indicator (VTI) in a multi-country survey of adult vaccination attitudes.

Improved uptake of adult vaccinations could substantially reduce the burden of infectious disease worldwide, however very few countries achieve high coverage of recommended adult vaccinations. Vaccine hesitancy is an important driver of low vaccine uptake among adults but no measure currently exists to capture general vaccination attitudes in this population accurately and efficiently. We utilize data from two surveys of adult vaccine attitudes and uptake conducted in fifteen countries to evaluate the Vaccination Trust Indicator (VTI). The VTI is a six-item measure intended to capture general vaccine attitudes. We utilized multivariable logistic regression to examine the association between VTI scores and self-reported receipt of the seasonal influenza vaccine, receipt of a tetanus toxoid-containing vaccine and intent to receive the flu vaccine in the next season. In the five countries with self-reported vaccine receipt data, we found that a ten-point increase in VTI score was associated with a 50% increase in odds of influenza vaccine receipt (OR = 1.55, 95% CI = 1.48, 1.62) and 25% increase in the odds of tetanus vaccine receipt (OR = 1.26, 95% CI = 1.21, 1.30). Strong associations between VTI score and vaccine receipt were found in each country except China. A strong association between VTI score and intent to receive the influenza vaccine was found in all fifteen countries. The VTI is a promising tool for assessing adult immunization attitudes with clear and immediate uses for immunization programs globally.

Incentivizing COVID-19 Vaccination in a Polarized and Partisan United States.

As COVID-19 vaccines were rolled out in early 2011, governments at all levels in the US faced significant difficulty in consistently and efficiently administering injections in the face of vaccination resistance among a public increasingly political polarized on vaccination preferences prior to the beginning of the mass vaccinations. Using an original conjoint experiment fielded to a nationally representative sample prior to the mass proliferation of COVID-19 vaccines, we examine how different incentives (e.g., employer mandates, state-organized or health care provider-organized vaccination clinics, or financial incentives) affect the public's preference to get vaccinated. We also test how financial incentive preferences correlate with self-reported vaccination intention using observational data from the Kaiser Family Foundation June 2021 Health Tracking Poll. We find financial incentives positively influence vaccine preferences among the mass public and all partisan groups, including Republicans initially "unlikely" to be vaccinated. Using the observational data, we replicate our experimental findings showing positive financial incentive attitudes positively correlate with self-reported vaccination disclosures. Our results provide support for direct financial incentives, rather than other incentives, as being a valuable tool for policymakers tasked with alleviating vaccination resistance among a US mass public increasingly polarized along partisan lines.

Real-world uptake of COVID-19 vaccination among individuals expressing vaccine hesitancy: A registry-linkage study.

Uptake of COVID-19 vaccination remains suboptimal in the United States and other settings. Though early reports indicated that a strong majority of people were interested in receiving the COVID-19 vaccine, the association between vaccine intention and uptake is not yet fully understood. Ourobjective was todescribe predictors of vaccine uptake, and estimate the sensitivity, specificity, and predictive values of self-reported COVID-19 vaccine status compared to a comprehensive statewide COVID-19 vaccine registry. A cohort of California residents that received a molecular test for SARS-CoV-2 infection during 24 February-5 December 2021 were enrolled in a telephone-administered survey. Survey participants were matched with records in a statewide immunization registry. Cox proportional hazards model were used to compare time to vaccination among those unvaccinated at survey enrollment by self-reported COVID-19 vaccination intention. Among 864 participants who were unvaccinated at the time of interview, 272 (31%) had documentation of receipt of COVID-19 vaccination at a later date; including 194/423 (45.9%) who had initially reported being willing to receive vaccination, 41/185 (22.2%) who reported being unsure about vaccination, and 37/278 (13.3%) who reported unwillingness to receive vaccination.Adjusted hazard ratios (aHRs) for registry-confirmed COVID-19 vaccination were 0.49 (95% confidence interval: 0.32-0.76) and 0.21 (0.12-0.36) for participants expressing uncertainty and unwillingness to receive vaccination, respectively, as compared with participants who reported being willing to receive vaccination. Time to vaccination was shorter among participants from higher-income households (aHR=3.30 [2.02-5.39]) and who reported co-morbidities or immunocompromising conditions (aHR=1.54 [1.01-2.36]).Sensitivity of self-reported COVID-19 vaccination status was 82% (80-85%) overall, and 98% (97-99%) among those referencing vaccination records; specificity was 87% (86-89%). Willingness to receive COVID-19 vaccination was an imperfect predictor of real-world vaccine uptake. Improved messaging about COVID-19 vaccination regardless of previous SARS-CoV-2 infection status may help improve uptake.

Pharmacists’ attitudes toward influenza vaccination: does the COVID-19 pandemic make a difference?

BackgroundInfluenza vaccine uptake in most European countries remains low, despite the World Health Organization's target of 75%. Community pharmacists play a vital role in promoting vaccination; however, they have been reported to be vaccine-hesitant. This study aimed to investigate changes in pharmacists' attitudes toward influenza vaccination since the onset of the COVID-19 pandemic, as well as their COVID-19 vaccination intentions. MethodsIn December 2020, all members of the Swiss Association of Pharmacists were invited to participate in an online, cross-sectional survey. This study assessed pharmacists' attitudes toward influenza vaccination by surveying influenza vaccine uptake during the 2019–20 influenza season and possible reasons for their decision(s), in addition to their intention to receive COVID-19 and seasonal influenza vaccination(s) during the 2020–21 influenza season. Descriptive analysis and multinomial logistic regression were used to assess predictors of vaccine uptake and intention. ResultsOf 5900 Swiss pharmacists, 569 (9.6%) completed the survey. The self-reported influenza vaccination coverage among pharmacists during the 2019–20 season was 48.0%. The primary reason for vaccine uptake was the belief that all healthcare workers should be vaccinated, whereas the main reason for refusal was a lack of concern about contracting influenza. The proportions of participants who intend to accept influenza and COVID-19 vaccinations in the 2020–2021 season, when available, were 63.3% and 66.5%, respectively. The most important predictor of high willingness to be vaccinated against influenza in 2020–21 was vaccination history (OR = 3.73; 95% CI = 1.47–9.50), while the most critical predictor of willingness to be vaccinated against COVID-19 was the intention to be vaccinated against influenza (OR = 3.45; 95% CI = 1.74–6.84). ConclusionsFindings indicated that although pharmacists' readiness to accept seasonal influenza vaccination significantly increased during the COVID-19 pandemic, influenza vaccine uptake among them remains suboptimal. This is consistent with what has been reported in the literature.

Barriers to COVID-19 vaccine uptake among resource-limited adults diagnosed with chronic illness.

Despite the use of interventions (e.g., monetary incentives, educational campaigns, on-site workplace vaccination) to increase COVID-19 vaccination, differences in uptake persist by poverty level, insurance status, geography, race, and ethnicity, suggesting that these interventions may not be adequately addressing the barriers faced by these populations. Among a sample of resource-limited individuals with chronic illnesses, we (1) described the prevalence of different types of barriers to the COVID-19 vaccination and (2) identified associations between patients' sociodemographic characteristics and barriers to vaccination. We surveyed a national sample of patients with chronic illness and demonstrated healthcare affordability and/or access challenges about barriers to COVID-19 vaccination in July 2021. We categorized participant responses into cost, transportation, informational, and attitudinal barrier domains and assessed the prevalence of each domain, both overall and by self-reported vaccination status. Using logistic regression models, we examined unadjusted and adjusted associations between respondent characteristics (sociodemographic, geographic, and healthcare access) and self-reported barriers to vaccination. Of 1,342 respondents in the analytic sample, 20% (264/1,342) reported informational barriers and 9% (126/1,342) reported attitudinal barriers to COVID-19 vaccination. Transportation and cost barriers were reported much less commonly, by only 1.1% (15/1,342) and 0.7% (10/1,342) of the sample, respectively. Controlling for all other characteristics, respondents with either a specialist as their usual source of care or no usual source of care had an 8.4 (95% CI: 1.7-15.1) and 18.1 (95% CI: 4.3-32.0) percentage point higher predicted probability, respectively, of reporting informational barriers to care. Compared to females, males had an 8.4% point (95% CI: 5.5-11.4) lower predicted probability of reporting attitudinal barriers. Only attitudinal barriers were associated with COVID-19 vaccine uptake. Among a sample of adults with chronic illnesses who had received financial assistance and case management services from a national non-profit, informational and attitudinal barriers were more commonly reported than logistical or structural access barriers (i.e., transportation and cost barriers). Interventions should target attitudinal barriers among patients with chronic illness, who may have particular concerns about the interaction of the vaccine with ongoing medical care. Additionally, interventions targeting informational barriers are particularly needed among individuals without a usual source of care.

Modelling COVID-19 vaccination status and adherence to public health and social measures, Eastern Mediterranean Region and Algeria.

To study the link between coronavirus disease 2019 (COVID-19) vaccination status and adherence to public health and social measures in Members of the Eastern Mediterranean Region and Algeria. We analysed two rounds of a large, cross-country, repeated cross-sectional mobile phone survey in June-July 2021 and October-November 2021. The rounds included 14 287 and 14 131 respondents, respectively, from 23 countries and territories. Questions covered knowledge, attitudes and practices around COVID-19, and demographic, employment, health and vaccination status. We used logit modelling to analyse the link between self-reported vaccination status and individuals' practice of mask wearing, physical distancing and handwashing. We used propensity score matching as a robustness check. Overall, vaccinated respondents (8766 respondents in round 2) were significantly more likely to adhere to preventive measures than those who were unvaccinated (5297 respondents in round 2). Odds ratios were 1.5 (95% confidence interval, CI: 1.3-1.8) for mask wearing; 1.5 (95% CI: 1.3-1.7) for physical distancing; and 1.2 (95% CI: 1.0-1.4) for handwashing. Similar results were found on analysing subsamples of low- and middle-income countries. However, in high-income countries, where vaccination coverage is high, there was no significant link between vaccination and preventive practices. The association between vaccination status and adherence to public health advice was sustained over time, even though self-reported vaccination coverage tripled over 5months (19.4% to 62.3%; weighted percentages). Individuals vaccinated against COVID-19 maintained their adherence to preventive health measures. Nevertheless, reinforcement of public health messages is important for the public's continued compliance with preventive measures.

COVID-19 vaccine hesitancy scale and its association with actual COVID-19 vaccine uptake in Israel.

The public's willingness to get vaccinated continues to be a source of concern. In this study we assessed the psychometric properties of the COVID-19 vaccine hesitancy scale (C19-VHS) as well as the association between the scale and self-reported past COVID-19 vaccination, approximately two weeks after the national vaccine distribution plan was launched in Israel. Participants were recruited via an online survey distributed through social media platforms and mailing lists. A total of 650 individuals completed the C19-VHS, the general vaccine hesitancy scale, and the fear of COVID-19 scale, and reported on demographic and pandemic-related characteristics. Principal component and Cronbach's alpha analyses were performed to assess the factor structure and reliability of the scale. Logistic regressions were employed to assess the scale's convergent and discriminative validity. Two factors pertaining to "lack of confidence" (Factor 1) and "risk perception" (Factor 2) emerged. Cronbach's alpha indicated good reliability of Factor 1 (0.93), with lower reliability of Factor 2 (0.72). Younger age was associated with higher risk perception, with women showing less confidence and perceiving greater risks. Lower hesitancy significantly predicted actual COVID-19 vaccine uptake after adjusting for demographic and pandemic-related factors (OR=1.16, 95%CI 1.11-1.21, p<.001). Older age, being a woman, and receiving the flu vaccine in the past year were also predictive of COVID-19 vaccine uptake. The C19-VHS measure shows robust psychometric properties and is associated with actual vaccine uptake. Future studies assessing COVID-19 vaccination attitudes may utilize this scale to assess current COVID-19 vaccine hesitancy in different contexts and cultures.

Self-reported Human Papillomavirus Vaccination and Vaccine Effectiveness Among Men Who Have Sex with Men: A Quantitative Bias Analysis.

Self-report of human papillomavirus (HPV) vaccination has ~80-90% sensitivity and ~75-85% specificity. We measured the effect of nondifferential exposure misclassification associated with self-reported vaccination on vaccine effectiveness (VE) estimates. Between 2017-2019, we recruited sexually active gay, bisexual, and other men who have sex with men aged 16-30 years in Canada. VE was derived as 1-prevalence ratio × 100% for prevalent anal HPV infection comparing vaccinated (≥1 dose) to unvaccinated men using a multivariable modified Poisson regression. We conducted a multidimensional and probabilistic quantitative bias analysis to correct VE estimates. Bias-corrected VE estimates were relatively stable across sensitivity values but differed from the uncorrected estimate at lower values of specificity. The median adjusted VE was 27% (2.5-97.5th simulation interval = -5-49%) in the uncorrected analysis, increasing to 39% (2.5-97.5th simulation interval = 2-65%) in the bias-corrected analysis. A large proportion of participants erroneously reporting HPV vaccination would be required to meaningfully change VE estimates.

Behavioral and Social Drivers of COVID-19 Vaccination in the United States, August–November 2021

COVID-19 vaccines are safe, effective, and widely available, but many adults in the U.S. have not been vaccinated for COVID-19. This study examined the associations between behavioral and social drivers of vaccination with COVID-19 vaccine uptake in the U.S. adults and their prevalence by region. A nationally representative sample of U.S. adults participated in a cross-sectional telephone survey in August-November 2021; the analysis was conducted in January 2022. Survey questions assessed self-reported COVID-19 vaccine initiation, demographics, and behavioral and social drivers of vaccination. Among the 255,763 respondents, 76% received their first dose of COVID-19 vaccine. Vaccine uptake was higher among respondents aged ≥75 years (94%), females (78%), and Asian non-Hispanic people (94%). The drivers of vaccination most strongly associated with uptake included higher anticipated regret from nonvaccination, risk perception, and confidence in vaccine safety and importance, followed by work- or school-related vaccination requirements, social norms, and provider recommendation (all p<0.05). The direction of association with uptake varied by reported level of difficulty in accessing vaccines. The prevalence of all of these behavioral and social drivers of vaccination was highest in the Northeast region and lowest in the Midwest and South. This nationally representative survey found that COVID-19 vaccine uptake was most strongly associated with greater anticipated regret, risk perception, and confidence in vaccine safety and importance, followed by vaccination requirements and social norms. Interventions that leverage these social and behavioral drivers of vaccination have the potential to increase COVID-19 vaccine uptake and could be considered for other vaccine introductions.

Vaccine Effectiveness Against 12-Month Incident and Persistent Anal Human Papillomavirus Infection Among Gay, Bisexual, and Other Men Who Have Sex With Men.

Real-world evidence of human papillomavirus (HPV) vaccine effectiveness (VE) against longitudinal outcomes is lacking among gay, bisexual, and other men who have sex with men (GBM). We compared 12-month incidence and persistence of anal HPV infection between vaccinated and unvaccinated GBM. We recruited GBM aged 16-30 years in Montreal, Toronto, and Vancouver, Canada, from 2017 to 2019. Participants were followed over a median of 12 months (interquartile range, 12-13 months). Participants self-reported HPV vaccination and self-collected anal specimens for HPV DNA testing. We calculated prevalence ratios (PR) for 12-month cumulative incidence and persistence with ≥1 quadrivalent vaccine type (HPV 6/11/16/18) between vaccinated (≥1 dose at baseline) and unvaccinated participants using a propensity score-weighted, modified Poisson regression. Among 248 participants, 109 (44.0%) were vaccinated at baseline, of whom 62.6% received 3 doses. PRs for HPV 6/11/16/18 were 0.56 (95% confidence interval [CI], .24-1.31) for cumulative incidence and 0.53 (95% CI, .25-1.14) for persistence. PRs were 0.23 (95% CI, .05-1.03) and 0.08 (95% CI, .01-.59) for incidence and persistence, respectively, among participants who received their first dose at age ≤23 years and 0.15 (95% CI, .03-.68) and 0.12 (95% CI, .03-.54) among participants who were sexually active for ≤5 years before vaccination. Findings support national recommendations for HPV vaccination at younger ages or soon after sexual debut.