Neighborhood determinants of 2009 pandemic A/H1N1 influenza vaccination in Montreal, Quebec, Canada

Immunization information systems' implementation and characteristics across the world: a systematic review of the literature

INTRODUCTION

Immunization Information Systems (IISs) are essential public health tools, supporting the management and analysis of vaccination data to aid clinical and strategic decision-making.

METHODS

Following PRISMA guidelines, this systematic review investigated global state and operational characteristics of IISs. A comprehensive search across multiple databases up to 6 June 2023, identified 2,612 articles, with 238 included.

RESULTS

A significant increase in IIS research was observed in recent years, with a strong preference (84.5%) for electronic immunization registries (EIRs). Notably, 36% of IISs operate at the national level, and 47.7% meet the U.S. CDC definition, 17.0% are interoperable with personal health records, and 11.7% provide direct access to vaccination data for vaccinees or their guardians. Other key features include automated reminder systems for recipients and providers (12.1%), near real-time or real-time data entry (11.0%), the inclusion of demographic and socioeconomic data (16.7%), and the capacity to document vaccine refusal or hesitancy (10.2%).

CONCLUSIONS

IISs contribute to improving population-level surveillance of vaccine-preventable diseases. Persistent limitations related to data standardization, interoperability, and cost-effectiveness evaluation must be addressed. Strengthening these aspects is crucial to fully harness the potential of IISs in various healthcare settings, where enhanced vaccination tracking and targeting are most urgently needed.

Supply, then demand? Health expenditure, political leanings, cost obstacles to care, and vaccine hesitancy predict state-level COVID-19 vaccination rates

OBJECTIVES

To examine predictors of state-level COVID-19 vaccination rates during the first nine months of 2021.

METHODS

Using publicly available data, we employ a robust, iteratively re-weighted least squares multivariable regression with state characteristics as the independent variables and vaccinations per capita as the outcome. We run this regression for each day between February 1 and September 21, the last day before vaccine booster rollout.

RESULTS

We identify associations between vaccination rates and several state characteristics, including health expenditure, vaccine hesitancy, cost obstacles to care, Democratic voting, and elderly population share. We show that the determinants of vaccination rates have evolved: while supply-side factors were most clearly associated with early vaccination uptake, demand-side factors have become increasingly salient over time. We find that our results are generally robust to a range of alternative specifications.

CONCLUSIONS

Both supply and demand-side factors relate to vaccination coverage and the determinants of success have changed over time.

POLICY IMPLICATIONS

Investing in health capacity may improve early vaccine distribution and administration, while overcoming vaccine hesitancy and cost obstacles to care may be crucial for later immunisation campaign stages.

An equity-based assessment of immunization-related responses in urban Alberta during the 2014 measles outbreak: a comparative analysis between Calgary and Edmonton

OBJECTIVES

This study investigates measles, mumps, and rubella (MMR) immunization rates during the measles outbreak in Calgary and Edmonton of 2014 stratified by four area-level socio-demographic indicators. This study also leverages this epidemiological data to assess the equity aspect of emergency measures instituted regarding immunization in those two cities.

METHODS

A mixed-methods comparative case study analysis methodology was employed to assess the neighbourhood-level immunization statuses before (2013), during (2014), and after (2015) an active measles outbreak in Calgary and Edmonton, Alberta, Canada. The epidemiological one-dose by age-2 MMR coverage data were stratified using four socio-demographic indicators: median household income, %-homeownership, %-Aboriginal population, and %-immigrant population. Document and content analysis was utilized to investigate the outbreak mitigation strategies deployed in each city.

RESULTS

The measles outbreak of 2013/2014 involved the entirety of Alberta and led to both provincial and city-specific interventions in which Calgary deployed three mass immunization clinics in 2014, where Edmonton did not. The Calgary coverage data showed an increase in coverage inequalities across all indicators and the Edmonton data showed mixed results in terms of equity gains/losses. Calgary's additive intervention of three mass immunization clinics in 2014 appears to have contributed to both the higher gross immunization rates in Calgary (90.77%) and an inequitable increase in coverage rates as compared with Edmonton (88.96%), in most cases.

CONCLUSION

Public health policy-makers must be cognizant that large-scale public health efforts must be optimized for accessibility across all socio-economic levels to ensure public and population health gains are realized equitably.

Sidek Ahmad Z, Zarkasi K, Ramli N, Che Jamaludin F. Pretravelling health-seeking behavior, knowledge of vaccines, and attitudes toward travel health among malaysian travelers

Background:

Travelers are at higher risk of developing health-related problems, especially travel-related diseases, and this remains a major public health burden.

Aims:

To assess pretravel health behavior-seeking factors, knowledge of vaccine, and travel health attitudes. A cross-sectional design among Malaysian travelers.

Methods:

An online survey was conducted from December 2017 till March 2018 among 226 participants. Demographic data, pretraveling health behaviors, knowledge of vaccine-preventable diseases, and travel health were asked. Independent t-test and ANOVA were performed using SPSS version 20.

Results:

Among travelers, 51.3% and 63.7% used health-related information on their destination before departure and collected information on possible travel hazards at their destination. Participant age (P = 0.02), monthly income (P = 0.01), predeparture health information (P = 0.03), information on possible hazards (P = 0.04), and travel health advice from medical professionals (P = 0.03) have been reported as a major predictor of knowledge of vaccine-preventable disease. Travelers’ gender (P = 0.01), household income (P = 0.01), and travel health advice from professionals (P = 0.002) were significantly associated with travel health attitude.

Conclusions:

Sociodemographic and pretravel health-seeking behavior influence knowledge of vaccine-preventable disease and attitudes towards travel health which requires a public health need for community outreach programs targeting this group.

Identifying people at risk for influenza with low vaccine uptake based on deprivation status: a systematic review

BACKGROUND

Influenza vaccination is an important public health intervention for controlling disease burden, but coverage rates are still low also in risk groups. In order to identify non-vaccinating subgroups, deprivation and socio-economic indices, i.e. measures used to synthetically describe people's socio-economic status while taking into account several dimensions, may be used. We aimed to synthetize evidence from studies investigating association between deprivation/socio-economic indices and influenza vaccination coverage in population at risk-persons ≥65 years of age, individuals with comorbidities, pregnant women and health-care workers.

METHODS

We searched PubMed, ISI WoS, CINAHL and Scopus to identify observational studies published up to October 10th 2017 in English or Italian. Studies reporting quantitative estimates of the association between deprivation/socio-economic indices and influenza vaccination coverage in populations at risk were included.

RESULTS

A total of 1474 articles were identified and 12 were eventually included in the final review. Studies were mostly cross-sectional, performed in European countries, from 2004 to 2017. Seven studies focussed on deprivation and five on socio-economic indices. Studies on deprivation indices and vaccination coverage showed that people from the most deprived areas had lower coverage. Regarding socio-economic condition, results were contrasting, even though it may also be concluded that people from lower groups have lower vaccination coverage.

CONCLUSIONS

Our work supports the possibility to identify people likely to have lower influenza vaccination coverage based on deprivation/socio-economic indices. Efforts should be performed in order to further strengthen robustness, transferability and suitability of these indices in addressing public health problems.

An exploration of the impact of SARS-CoV-2 (COVID-19) restrictions on marginalised groups in the UK

Background

To contain the spread of COVID-19 within the UK over the past year, there have been a series of local and national lockdowns. These restrictions are likely to have impacted upon the health and well-being of marginalised groups who rely on now closed social and community support services to stay healthy. An understanding of the experiences of marginalised people is important; therefore, this study aimed to explore the impact of the COVID-19 restrictions on the health and well-being of marginalised groups in the UK.

Methods

In summer 2020, a rapid telephone survey was conducted by trained, trusted volunteers with 76 participants who were from marginalised groups. As part of this survey, 64 participants consented to describe their experience of lockdown. These case studies were thematically analysed to identify patterns of meaning.

Results

Findings indicate that lockdown led to the deterioration of health of participants, impacted adversely on their socio-economic positions and affected access to food and essential supplies. In addition, government public health messaging was considered confusing and inadequate.

Conclusions

This study highlights the need for pathways into services which support marginalised groups to remain accessible during periods of restrictions and essential supplies and food to be mapped and protected for marginalised individuals within our local communities.

Transforming public health using value lens and extended partner networks

INTRODUCTION

Organizational transformations have focused on creating and fulfilling value for customers, leveraging advanced technologies. Transforming public health (PH) faces an interesting challenge. The value created (preventive practices) to fulfill policy makers' desire to reduce healthcare costs is realized by several external partners with varying goals and is practiced by the public (value in use), which often places low priority on prevention.

METHODS

This paper uses value lens to argue that PH transformation strategy must align the goals of all stakeholders involved. This may include allowing partners and the public to contextualize the preventive practices to see the value in near term and as relevant. It also means extending the number of partners PH uses and helping them connect with the public to seek shared alignment in shared goals of value fulfillment and value-in-use.

RESULTS

Using lessons from Covid-19 and PH experience with partners in four different sectors: business, healthcare, public and community, the paper illustrates how PH transformation strategy can be implemented going forward.

CONCLUSIONS

We conclude the paper with five distinct directions for future research to create and sustain value using the framework of learning health systems.

The association between influenza vaccination and socioeconomic status in high income countries varies by the measure used: a systematic review

Background

The purpose of this paper is to systematically review the literature on the relationship between socioeconomic status (SES) and influenza immunization and to examine how certain measures of SES may influence interpretations of this relationship.

Methods

We conducted a systematic review of existing peer-reviewed literature to evaluate the above relationship in the general population. Electronic databases (MEDLINE and EMBASE) were searched from January 2012 to May 2017 to identify English-language studies relevant to this review. Studies were included where influenza vaccination was explicitly reported as the dependent variable and SES as the independent variable. We limited our review to measures of SES that focus on education, income, social class, occupation, and deprivation. Studies that measured SES using other variables (e.g., race, ethnicity, geographic location, rural or urban status, or insurance status) were excluded. Studies were also excluded if they did not report on the human population or did not analyze original data. The population of interest included all age groups, levels of health status, and sociodemographic backgrounds. The review was also limited to World Bank high-income countries. Two authors independently screened full-text articles after obtaining a Kappa score of K = 0.867. The methodological quality of manuscripts was assessed using the appraisal tools developed by the Joanna Briggs Institute. Results were qualitatively reported and synthesized.

Results

Of the 42 articles included in this review, 52.4% (n = 22) found that higher levels of SES resulted in higher levels of influenza vaccination; 4.5% (n = 2) reported a negative association; and 14.3% (n = 6) found no association. Just over a quarter (26.2%, n = 12) of articles reported mixed results.

Conclusions

There was consistently a relationship between SES and influenza immunization, which varied according to how SES was measured. It is recommended that authors be explicit in defining the SES concept they are trying to capture and that they utilize multiple measures of SES (e.g., education, income, class).

Electronic supplementary material

The online version of this article (10.1186/s12874-019-0801-1) contains supplementary material, which is available to authorized users.

Countering vaccine hesitancy through immunization information systems, a narrative review

Immunization is one of the most important public health interventions to contrast infectious disease; however, many people nowadays refuse vaccination. Vaccine hesitancy (VH) is due to several factors that influence the complex decision-making process. Information technology tools might play an important role in vaccination programs. In particular, immunization information systems (IISs) have the potential to improve performance of vaccination programs and to increase vaccine uptake. This review aimed to present IIS functionalities in order to counter VH. In detail, we analyzed the automatic reminder/recall system, the interoperability of the system, the decision support system, the web page interface and the possibility to record adverse events following immunization. IIS could concretely represent a valid instrument to increase vaccine confidence, especially trust in both health-care workers and decision makers. There are not enough trials aimed to evaluate the efficacy of IIS to counter VH. Further researches might focalize on this aspect.

A Systematic Review of Barriers to Vaccination During Pregnancy in the Canadian Context

OBJECTIVE

Although vaccination in pregnancy has the potential to affect maternal and infant morbidity and mortality dramatically, uptake of recommended vaccinations in pregnancy remains low. The objective of this study was to identify barriers and facilitators of vaccination during pregnancy in Canada.

METHODS

The Medline database and the tables of contents of four relevant Canadian journals were screened to identify all studies that considered barriers and/or facilitators to vaccination during pregnancy, specifically in Canadian settings. Citations were screened, and a narrative synthesis of findings was undertaken given the heterogeneity of study design.

RESULTS

In total, 17 studies met inclusion criteria, most with a focus on the seasonal and pandemic influenza vaccines. Facilitators and barriers were identified at the level of the patient and the provider. At both levels, knowledge was an important facilitator of vaccine acceptance during pregnancy and was notably improved in studies following the 2009 pandemic H1N1 influenza outbreak compared with earlier studies. Vaccine endorsement by a prenatal care provider and clear messages of safety for the fetus emerged as key motivators. Few studies addressed system-level barriers or interventions for improving vaccine uptake during pregnancy in the Canadian setting.

CONCLUSION

Common themes have emerged from the Canadian literature addressing barriers and facilitators of vaccination during pregnancy. However, there is a paucity of literature to suggest strategies to improve the uptake of vaccination during pregnancy in Canadian settings. Further research is urgently needed given the expanding role of vaccination during routine prenatal care.

Predictors of coverage of the national maternal pertussis and infant rotavirus vaccination programmes in England

This study assessed variation in coverage of maternal pertussis vaccination, introduced in England in October 2012 in response to a national outbreak, and a new infant rotavirus vaccination programme, implemented in July 2013. Vaccine eligible patients were included from national vaccine coverage datasets and covered April 2014 to March 2015 for pertussis and January 2014 to June 2016 for rotavirus. Vaccine coverage (%) was calculated overall and by NHS England Local Team (LT), ethnicity and Index of Multiple Deprivation (IMD) quintile, and compared using binomial regression. Compared with white-British infants, the largest differences in rotavirus coverage were in ‘other’, white-Irish and black-Caribbean infants (−13·9%, −12·1% and −10·7%, respectively), after adjusting for IMD and LT. The largest differences in maternal pertussis coverage were in black-other and black-Caribbean women (−16·3% and −15·4%, respectively). Coverage was lowest in London LT for both programmes. Coverage decreased with increasing deprivation and was 14·0% lower in the most deprived quintile compared with the least deprived for the pertussis programme and 4·4% lower for rotavirus. Patients’ ethnicity and deprivation were therefore predictors of coverage which contributed to, but did not wholly account for, geographical variation in coverage in England.

Pandemic influenza 2009: Impact of vaccination coverage on critical illness in children, a Canada and France observational study

AIM

To study the impact of vaccination critical illness due to H1N1pdm09, we compared the incidence and severity of H1N1pdm09 infection in Canada and France.

METHODS

We studied two national cohorts that included children with documented H1N1pdm09 infection, admitted to a pediatric intensive care unit (PICU) in Canada and in France between October 1, 2009 and January 31, 2010.

RESULTS

Vaccination coverage prior to admission to PICUs was higher in Canada than in France (21% vs 2% of children respectively, P < 0.001), and in both countries, vaccination coverage prior to admission of these critically ill patients was substantially lower than in the general pediatric population (P < 0.001). In Canada, 160 children (incidence = 2.6/100000 children) were hospitalized in PICU compared to 125 children (incidence = 1.1/100000) in France (P < 0.001). Mortality rates were similar in Canada and France (4.4% vs 6.5%, P = 0.45, respectively), median invasive mechanical ventilation duration and mean PICU length of stay were shorter in Canada (4 d vs 6 d, P = 0.02 and 5.7 d vs 8.2 d, P = 0.03, respectively). H1N1pdm09 vaccination prior to PICU admission was associated with a decreased risk of requiring invasive mechanical ventilation (OR = 0.30, 95%CI: 0.11-0.83, P = 0.02).

CONCLUSION

The critical illness due to H1N1pdm09 had a higher incidence in Canada than in France. Critically ill children were less likely to have received vaccination prior to hospitalization in comparison to general population and children vaccinated had lower risk of ventilation.

A Meta-Analysis of the Association between Gender and Protective Behaviors in Response to Respiratory Epidemics and Pandemics

Respiratory infectious disease epidemics and pandemics are recurring events that levy a high cost on individuals and society. The health-protective behavioral response of the public plays an important role in limiting respiratory infectious disease spread. Health-protective behaviors take several forms. Behaviors can be categorized as pharmaceutical (e.g., vaccination uptake, antiviral use) or non-pharmaceutical (e.g., hand washing, face mask use, avoidance of public transport). Due to the limitations of pharmaceutical interventions during respiratory epidemics and pandemics, public health campaigns aimed at limiting disease spread often emphasize both non-pharmaceutical and pharmaceutical behavioral interventions. Understanding the determinants of the public’s behavioral response is crucial for devising public health campaigns, providing information to parametrize mathematical models, and ultimately limiting disease spread. While other reviews have qualitatively analyzed the body of work on demographic determinants of health-protective behavior, this meta-analysis quantitatively combines the results from 85 publications to determine the global relationship between gender and health-protective behavioral response. The results show that women in the general population are about 50% more likely than men to adopt/practice non-pharmaceutical behaviors. Conversely, men in the general population are marginally (about 12%) more likely than women to adopt/practice pharmaceutical behaviors. It is possible that factors other than pharmaceutical/non-pharmaceutical status not included in this analysis act as moderators of this relationship. These results suggest an inherent difference in how men and women respond to epidemic and pandemic respiratory infectious diseases. This information can be used to target specific groups when developing non-pharmaceutical public health campaigns and to parameterize epidemic models incorporating demographic information.

Influenza immunization among Canadian health care personnel: a cross-sectional study

BACKGROUND

Influenza immunization coverage among Canadian health care personnel remains below national targets. Targeting this group is of particular importance given their elevated risk of influenza infection, role in transmission and influence on patients' immunization status. We examined influenza immunization coverage in health care personnel in Canada, reasons for not being immunized and the impact of "vaccinate-or-mask" influenza prevention policies.

METHODS

In this national cross-sectional study, we pooled data from the 2007 to 2014 cycles of the Canadian Community Health Survey and restricted it to respondents who reported a health care occupation. Using bootstrapped survey weights, we examined immunization coverage by occupation and by presence of vaccinate-or-mask policies, and reasons for not being immunized. We used modified Poisson regression to estimate the prevalence ratio (PR) of influenza immunization for health care occupations compared with the general working population.

RESULTS

For all survey cycles combined, 50% of 18 446 health care personnel reported receiving seasonal influenza immunization during the previous 12 months, although this varied by occupation type (range 4%-72%). Compared with the general working population, family physicians and general practitioners were most likely to be immunized (PR 3.15, 95% confidence interval [CI] 2.76-3.59), whereas chiropractors, midwives and practitioners of natural healing were least likely (PR 0.17, 95% CI 0.10-0.30). Among those who were not immunized, the most frequently cited reason was the belief that influenza immunization is unnecessary. Introduction of vaccinate-or-mask policies was associated with increased influenza immunization among health care personnel.

INTERPRETATION

Health care personnel are more likely to be immunized against influenza than the general working population, but coverage remains suboptimal overall, and we observed wide variation by occupation type. More efforts are needed to target specific health care occupations with low immunization coverage.

Neighborhood Influences on Seasonal Influenza Vaccination among Older African Americans in Atlanta, Georgia

BACKGROUND

Influenza vaccination coverage in the US is lower than the recommended Healthy People 2020 threshold, especially among older African Americans. This analysis explores the complex relationship among neighborhood-level factors, socio behavioral influences, and influenza vaccination outcomes among older African Americans.

METHODS

We analyzed data from 221 Black/African American participants' age ≥50 years living in Atlanta, Georgia. Generalized Estimating Equations for linear and logistic models assessed associations among socio demographic factors, census-tract neighborhood characteristics, and reported 2012-2013 seasonal influenza vaccination receipt, controlling for correlations among individuals within the same census tracts. Evaluated environmental factors included neighborhood deprivation indicators such as vacant housing percentage, vehicle availability, area violent crimes, and racial/ethnic composition.

RESULTS

Reported greater influenza immunization uptake was significantly associated with older age ≥65 years [OR=1.05, p=0.04], positive vaccination attitudes [OR=5.30, p<0.01], having health insurance [OR=14.37, p=0.03], lower perceived neighborhood security [OR=0.51, p=0.02], and lower neighborhood vehicle ownership [OR=1.07, p=0.04], a proxy for neighborhood affluence and transportation ease. Having a post-secondary education was significantly associated with both positive perceived neighborhood security [β=0.28, p=0.02] and positive vaccination attitudes [β=0.27, p=0.02].

CONCLUSION

The findings provide evidence for distal neighborhood-level influences on influenza vaccination uptake among older African Americans. Lower vehicle ownership and lower perceived neighborhood security influenced seasonal influenza immunizations. Those who perceived personal risk, based on reported neighborhood security, displayed intent to obtain the seasonal influenza vaccine. Further investigation of multilevel, socio geographic factors is therefore warranted to more effectively address suboptimal influenza vaccine coverage among this population.

Geospatial patterns in influenza vaccination: evidence from uninsured and publicly insured children in North Carolina

BACKGROUND

The purpose of this study was to explore geospatial patterns in influenza vaccination.

METHODS

We conducted an ecological analysis of publicly funded influenza vaccinations at the ZIP code tabulation area (ZCTA) level using secondary data for publicly funded influenza vaccinations among eligible school-aged children (age range, 5-17 years) for the 2010-2011 and 2011-2012 influenza seasons from the North Carolina Immunization Registry (NCIR). NCIR data were merged by ZCTA with other publicly available data. We tested for spatial autocorrelation in unadjusted influenza vaccination rates using choropleth maps and Moran's I. We estimated nonspatial and spatial negative binomial models with spatially correlated random effects adjusted for demographic, economic, and health care variables. The study was conducted at the University of North Carolina at Chapel Hill in the spring of 2014.

RESULTS

The NCIR demonstrated spatial autocorrelation in publicly funded influenza vaccinations among uninsured and means-tested, publicly insured school-aged children; ZCTAs tended to have influenza vaccination rates that were similar to their neighbors. This result was partially explained by included ZCTA characteristics, but not wholly.

CONCLUSION

To the extent that the geospatial clustering of vaccination rates is the result of social influences, targeting interventions to increase influenza vaccination among school-aged children in one area could also lead to increases in neighboring areas.

Relationship between local family physician supply and influenza vaccination after controlling for individual and neighborhood effects

BACKGROUND

Family physicians (FPs) play an important role in influenza vaccination. We investigated how local FP supply is associated with influenza vaccination, controlling for both individual-level and county-level characteristics.

METHODS

The 2008-2010 individual-level data from the Behavioral Risk Factor Surveillance System were merged with county-level data from the Area Resource File (n = 985,157). Multivariate logistic analyses were performed to predict influenza vaccination using the number of FPs per 1000 population as the key predictor, adjusting for individual-level demographic, socioeconomic, and health information, as well as county-level racial composition and income level. Additional analyses were performed across racial/ethnic and employment status categories.

RESULTS

Increasing local FP supply was associated with higher odds (adjusted odds ratio [aOR], 1.58; 95% confidence interval [CI], 1.49-1.67) and varied across racial/ethnic groups (Hispanic: aOR, 2.05, 95% CI, 1.55-2.72; non-Hispanic white: aOR, 1.57, 95% CI, 1.48-1.66; non-Hispanic black: aOR, 1.49, 95% CI, 1.18-1.89), employment status categories, and county types.

CONCLUSIONS

FP supply was significantly associated with influenza vaccination. The association was greatest among those who were Hispanic, residing in a rural area, or out of work. Our findings lend support to initiatives aimed at increasing the FP supply, particularly among disadvantaged populations.

H1N1 pandemic: clinical and epidemiologic characteristics of the Canadian pediatric outbreak

Canada was one of the first countries affected by the 2009 influenza H1N1 pandemic with two waves - one from May to June and one from October to December. The 2009 influenza H1N1 pandemic had many unique features when compared with seasonal influenza, including the following: more than half of the affected people were children; asthma was the most significant risk factor for hospital admission; and Aboriginal and pregnant women had a higher risk of hospital admission and complications. Antiviral therapy was widely used but data did not show any effect on the pediatric population. Outbreak spread was possibly promoted from child-child and child-adult contact, and therefore the vaccination campaign targeted the pediatric population and achieved good coverage among young children (57%). Vaccination efficacy was difficult to test because of the vaccination delay. Improvement in models of prevention and treatment are urgently needed to prepare for the possible future pandemics.

Clinic accessibility and clinic-level predictors of the geographic variation in 2009 pandemic influenza vaccine coverage in Montreal, Canada

Background

Nineteen mass vaccination clinics were established in Montreal, Canada, as part of the 2009 influenza A/H1N1p vaccination campaign. Although approximately 50% of the population was vaccinated, there was a considerable variation in clinic performance and community vaccine coverage.

Objective

To identify community- and clinic-level predictors of vaccine uptake, while accounting for the accessibility of clinics from the community of residence.

Methods

All records of influenza A/H1N1p vaccinations administered in Montreal were obtained from a vaccine registry. Multivariable regression models, specifically Bayesian gravity models, were used to assess the relationship between vaccination rates and clinic accessibility, clinic-level factors, and community-level factors.

Results

Relative risks compare the vaccination rates at the variable's upper quartile to the lower quartile. All else being equal, clinics in areas with high violent crime rates, high residential density, and high levels of material deprivation tended to perform poorly (adjusted relative risk [ARR]: 0·917, 95% CI [credible interval]: 0·915, 0·918; ARR: 0·663, 95% CI: 0·660, 0·666, ARR: 0·649, 95% CI: 0·645, 0·654, respectively). Even after controlling for accessibility and clinic-level predictors, communities with a greater proportion of new immigrants and families living below the poverty level tended to have lower rates (ARR: 0·936, 95% CI: 0·913, 0·959; ARR: 0·918, 95% CI: 0·893, 0·946, respectively), while communities with a higher proportion speaking English or French tended to have higher rates (ARR: 1·034, 95% CI: 1·012, 1·059).

Conclusion

In planning future mass vaccination campaigns, the gravity model could be used to compare expected vaccine uptake for different clinic location strategies.