Can high overall human papillomavirus vaccination coverage hide sociodemographic inequalities? An ecological analysis in Canada

BACKGROUND

Human papillomavirus (HPV) vaccination programs have been implemented in more than 50 countries. These programs offer tremendous promise of reducing HPV-related disease burden. However, failure to achieve high coverage among high-risk groups may mitigate program success and increase inequalities. We examined sociodemographic inequalities in HPV vaccination coverage in 4 Canadian provinces (Quebec (QC), Ontario (ON), Manitoba (MB), British Columbia (BC)).

METHODS

We obtained annual HPV vaccination coverage of pre-adolescent girls at provincial and regional levels, from the start of programs to 2012/2013. Regions refer to administrative areas responsible for vaccine implementation and monitoring (there are 18/36/10/16 regions in QC/ON/MB/BC). We obtained regions' sociodemographic characteristics from Statistics Canada Census. We used univariate weighted linear regression to examine the associations between regions' sociodemographic characteristics and HPV vaccination coverage.

RESULTS

Provincial HPV vaccination coverage is generally high (QC:78%; ON:80%; MB:64%, BC:69%, 2012/13). QC had the highest provincial vaccination coverage since the program start, but had the greatest inequalities. In QC, regional HPV vaccination coverage was lower in regions with higher proportions of socially deprived individuals, immigrants, and/or native English speakers (p<0.0001). These inequalities remained stable over time. Regional-level analysis did not reveal inequalities in ON, MB and BC.

CONCLUSION

School-based HPV vaccination programs have resulted in high vaccination coverage in four Canadian provinces. Nonetheless, high overall coverage did not necessarily translate into equality in coverage. Future work is needed to understand underlying causes of inequalities and how this could impact existing inequalities in HPV-related diseases and overall program success.

An evaluation of the feasibility and usability of a proof of concept mobile app for adverse event reporting post influenza vaccination

The Canadian National Vaccine Safety network (CANVAS) gathers and analyzes safety data on individuals receiving the influenza vaccine during the early stages of annual influenza vaccination campaigns with data collected via participant surveys through the Internet. We sought to examine whether it was feasible to use a mobile application (app) to facilitate AEFI reporting for the CANVAS network. To explore this, we developed a novel smartphone app, recruited participants from a hospital influenza immunization clinic and by word of mouth and instructed them to download and utilize the app. The app reminded participants to complete the CANVAS AEFI surveillance surveys ("AEFI surveys") on day 8 and 30, a survey capturing app usability metrics at day 30 ("usability survey") and provided a mechanism to report AEFI events spontaneously throughout the whole study period. All survey results and spontaneous reports were recorded on a privacy compliant, cloud server. A software plug-in, Lookback, was used to record the on-screen experience of the app sessions. Of the 76 participants who consented to participate, 48(63%) successfully downloaded the app and created a profile. In total, 38 unique participants completed all of the required surveillance surveys; transmitting 1104 data points (survey question responses and spontaneous reports) from 83 completed surveys, including 21 usability surveys and one spontaneous report. In total, we received information on new or worsening health conditions after receiving the influenza vaccine from 11(28%) participants. Of the usability survey responses, 86% agreed or strongly agreed that they would prefer to use a mobile app based reporting system instead of a web-based system. The single spontaneous report received was from a participant who had also reported using the Day 8 survey. Of Lookback observable sessions, an accurate transmission proportion of 100% (n=290) was reported for data points. We demonstrated that a mobile app can be used for AEFI reporting, although download and survey completion proportions suggest potential barriers to adoption. Future studies should examine implementation of mobile reporting in a broader audience and impact on the quality of reporting of adverse events following immunization.

The cost-utility of integrated cervical cancer prevention strategies in the Ontario setting - Can we do better?

INTRODUCTION

A universal, publicly funded, school-based human papillomavirus (HPV) vaccination program in grade eight girls was initiated in Ontario in 2007. We present a cost-utility analysis of integrated cervical cancer prevention programs from the healthcare payer perspective.

METHODS

Our analysis was based on linked HPV transmission and disease history models. We obtained data from the literature, provincial surveys and Ontario population-based linked health administrative datasets. We modeled combinations of vaccination and screening strategies. We considered vaccination based on the Ontario experience, as well as conservative and optimistic scenarios, varying coverage, vaccine effectiveness and duration of protection. We considered 900 screening scenarios (screening start age: 21-70 years, screening interval: 3-20 years; 1-year time steps). The current schedule screens every 3 years starting at age 21 years. We examined (1) first vaccinated cohort (low herd-immunity), and (2) steady state, i.e. all cohorts were vaccinated (high herd-immunity).

RESULTS

Adding vaccination to the current screening schedule was cost-effective (<C$10,000/quality-adjusted life year (QALY)) across all scenarios. Delaying screening start and/or extending screening intervals increased both expected QALYs and cost, and increased overall NHB for screening schedules with a start age of 25-35 years and 3-10-year intervals for most scenarios.

CONCLUSION

Delaying screening start age and/or extending screening intervals in vaccinated cohorts is likely to be cost-effective. Consideration should be given to both the short- and long-term implications of health policy decisions, particularly for infectious disease interventions that require long time intervals to reach steady state.

Vaccination attitudes and mobile readiness: A survey of expectant and new mothers

Sub-optimal vaccination coverage and recent outbreaks of vaccine-preventable diseases serve as a reminder that vaccine hesitancy remains a concern. ImmunizeCA, a new smartphone app to help track immunizations, may address several reasons for not vaccinating. We conducted a study to describe demographic variables, attitudes, beliefs and information sources regarding pediatric vaccination in a sample of childbearing women who were willing to download an immunization app. We also sought to measure their current mobile usage behaviors and determine if there is an association between participant demographics, attitudes, beliefs and information sources regarding pediatric vaccination and mobile usage. We recruited participants using a combination of passive and active methods at a tertiary care hospital in Ottawa, Canada. We used surveys to collect demographic information, examine attitudes, behavior, and information sources regarding immunization and self-reported mobile phone usage. A total of 54 women participated. The majority had positive attitudes toward vaccination (96%) and intended to vaccinate their children (98%). Participants were interested in information on pediatric vaccination (94%), and found information from public health the most reliable and accessible (78%). Participants also trusted immunization information from their doctor or nurse and public health (83%) more than other sources. There was variability in participant use of mobile apps for other purposes. The median participant mobile readiness score was 3.2. We found no significant associations between participant age, behavior and attitudes regarding vaccination and mobile readiness scores. This is the first evaluation of mobile readiness for a smartphone app to track immunizations. Our findings suggest that there exists an opportunity to provide reliable information on vaccination through mobile devices to better inform the public, however predictors of individual engagement with these technologies merits further study.

The Epidemiology of Invasive Haemophilus influenzae Non-Serotype B Disease in Ontario, Canada from 2004 to 2013

Background

Since the widespread use of Haemophilus influenzae (Hi) type b (Hib) vaccines among children aged <5 years, an increase in invasive non-Hib disease incidence has been reported internationally. We sought to describe the epidemiology of invasive non-Hib disease in Ontario, Canada (population ~13.5 million).

Methods

Confirmed invasive non-Hib cases (non-typeable [NTHi] and serotypes a, c, d, e, and f) were obtained from the provincial laboratory data system from 2004–2013. Data were deterministically linked to the provincial reportable disease system to provide further case information. Antibiotic resistance data were analysed separately from 2010–2014. Descriptive analyses included incidence rates, age group, serotype, site of specimen collection and resistance patterns; ethnicity data were not available. Temporal trends were evaluated by Poisson regression and p-values <0.05 were considered significant.

Results

A total of 1307 cases of invasive non-Hib disease were included, increasing from 0.67 cases to 1.60 cases /100,000 from 2004 to 2013. Significant increases in the incidence of NTHi (0.50 to 1.28 cases/100 000 population), Hia (0.02 to 0.08 cases/100, 000) and Hif (0.13 to 0.18 cases/100, 000 population) were seen. Among persons aged 40–64 years, 3 Hi strains significantly increased over time; NTHi (0.22 to 0.99 cases/100, 000), Hia (0.00 to 0.06 cases/100, 000) and Hif (0.05 to 0.21 cases/100, 000). Among persons aged 65–84 years, there was a significant increase of NTHi (1.62 to 3.14 cases/100, 000) and Hia (0.00 to 0.34 cases/100, 000). Among persons aged 85+ years, only NTHi significantly increased from 4.89 to 10.28 cases/100, 000). Antimicrobial resistance (AMR) to ampicillin and clarithromycin was seen in greater than 25% of isolates but AMR did not increase over the duration of this study.

Conclusions

The incidence of invasive non-Hib disease has increased over time; NTHi, Hif and Hia are emerging pathogens, and should be monitored.

Simulation study of the effect of influenza and influenza vaccination on risk of acquiring Guillain-Barré syndrome

Under typical conditions, such as influenza incidence rates of >5% and vaccine effectiveness >60%, vaccination reduced risk.

It is unclear whether seasonal influenza vaccination results in a net increase or decrease in the risk for Guillain-Barré syndrome (GBS). To assess the effect of seasonal influenza vaccination on the absolute risk of acquiring GBS, we used simulation models and published estimates of age- and sex-specific risks for GBS, influenza incidence, and vaccine effectiveness. For a hypothetical 45-year-old woman and 75-year-old man, excess GBS risk for influenza vaccination versus no vaccination was −0.36/1 million vaccinations (95% credible interval −1.22 to 0.28) and −0.42/1 million vaccinations (95% credible interval, –3.68 to 2.44), respectively. These numbers represent a small absolute reduction in GBS risk with vaccination. Under typical conditions (e.g. influenza incidence rates >5% and vaccine effectiveness >60%), vaccination reduced GBS risk. These findings should strengthen confidence in the safety of influenza vaccine and allow health professionals to better put GBS risk in context when discussing influenza vaccination with patients.

Importance of ICD-10 coding directive change for acute gastroenteritis (unspecified) for rotavirus vaccine impact studies: illustration from a population-based cohort study from Ontario, Canada

BACKGROUND

In Ontario, Canada, we conducted an evaluation of rotavirus (RV) vaccine on hospitalizations and Emergency Department (ED) visitations for acute gastroenteritis (AGE). In our original analysis, any one of the International Classification of Disease, Version 10 (ICD-10) codes was used for outcome ascertainment: RV-specific- (A08.0), viral- (A08.3, A08. 4, A08.5), and unspecified infectious- gastroenteritis (A09). Annual age-specific rates per 10,000 population were calculated.

FINDINGS

The average monthly rate of AGE hospitalization for children under age two increased from 0.82 per 10,000 from January 2003 to March 2009, to 2.35 over the period of April 2009 to March 31, 2013. Similar trends were found for ED consultations and in other age groups. A rise in events corresponding to the A09 code was found when the outcome definition was disaggregated by ICD-10 code. Documentation obtained from the World Health Organization confirmed that a change in directive for the classification of unspecified gastroenteritis occurred with the release of ICD-10 in April 2009. AGE events previously classified under the code K52.9, are now classified under code A09.9.

CONCLUSIONS

Based on change in the classification of unspecified gastroenteritis we modified our outcome definition to also include unspecified non-infectious-gastroenteritis (K52.9). We recommend other investigators consider using both A09.9 and K52.9 ICD-10 codes for outcome ascertainment in future rotavirus vaccine impact studies to ensure that all unspecified cases of AGE are captured, especially if the study period spans 2009.

Global travel patterns and risk of measles in Ontario and Quebec, Canada: 2007-2011

BACKGROUND

In 2011 the largest measles outbreak in North America in a decade occurred in Quebec, Canada with over 700 cases. In contrast, measles activity in neighbouring province Ontario remained low (8 cases). Our objective was to determine the extent to which the difference could be explained by differing travel patterns.

METHODS

We explored the relationship between measles cases over 2007-2011, by importation classification, in Quebec and Ontario in relation to global travel patterns to each province using an ecological approach. Global measles exposure was estimated by multiplying the monthly traveler volume for each country of origin into Quebec or Ontario by the yearly measles incidence rate for the corresponding country. Visual inspection of temporal figures and calculation of Pearson correlation coefficients were performed.

RESULTS

Global measles exposure was similar in Ontario and Quebec. In Quebec, there was a nearly perfectly linear relationship between annual measles cases and its global measles exposure index over 2007-2011 (r = 0.99, p = 0.001). In contrast, there was a non-significant association in Ontario. The 2011 rise in Quebec's index was largely driven by a dramatic increase in measles activity in France the same year.

CONCLUSIONS

Global measles activity was associated with measles epidemiology in Quebec. Global measles exposure risk is higher in Ontario than Quebec. Differences in measles epidemiology between Ontario and Quebec from 2007-2011 are not explained by greater exposure in Quebec. A combination of alternative factors may be responsible, including differences in population susceptibility.

Correlation of Real Time PCR Cycle Threshold Cut-Off with Bordetella pertussis Clinical Severity

Bordetella pertussis testing performed using real-time polymerase chain reaction (RT-PCR) is interpreted based on a cycle threshold (Ct) value. At Public Health Ontario Laboratories (PHOL), a Ct value <36 is reported as positive, and Ct values ≥36 and <40 are reported as indeterminate. PHOL reported indeterminate results to physicians and public health units until May 2012, after which these results were only reported to physicians. We investigated the association between Ct value and disease symptom and severity to examine the significance of indeterminate results clinically, epidemiologically and for public health reporting. B. pertussis positive and indeterminate RT-PCR results were linked to pertussis cases reported in the provincial Integrated Public Health Information System (iPHIS), using deterministic linkage. Patients with positive RT-PCR results had a lower median age of 10.8 years compared to 12.0 years for patients with indeterminate results (p = 0.24). Hospitalized patients had significantly lower Ct values than non-hospitalized patients (median Ct values of 20.7 vs. 31.6, p<0.001). The proportion of patients reporting the most indicative symptoms of pertussis did not differ between patients with positive vs. indeterminate RT-PCR results. Taking the most indicative symptoms of pertussis as the gold-standard, the positive predictive value of the RT-PCR test was 68.1%. RT-PCR test results should be interpreted in the context of the clinical symptoms, age, vaccination status, prevalence, and other factors. Further information on interpretation of indeterminate RT-PCR results may be needed, and the utility of reporting to public health practitioners should be re-evaluated.

Twenty Years of Medically-Attended Pediatric Varicella and Herpes Zoster in Ontario, Canada: A Population-Based Study

OBJECTIVE

To determine if reductions in medically-attended pediatric varicella and herpes zoster occurred in Ontario, Canada, after publicly-funded varicella immunization was implemented in 2004.

METHODS

For fiscal years (FY) 1992-2011, we examined data on varicella and herpes zoster physician office visits, emergency department (ED) visits, hospitalizations (including for varicella-associated skin and soft tissue infections [SSTI]), and intensive care unit (ICU) admissions, among those aged <18 years. The pre-vaccine, privately-available, and vaccine program eras were FY1992-1998, FY1999-2003, and FY2004-2011, respectively. We used Poisson regressionand Kruskal-Wallis tests (all at the p<0.05 level of significance), and compared rates using incidence rate ratios (IRRs) and 95% confidence intervals (CIs).

RESULTS

Incidence of varicella office visits declined over the study period from a high of 25.1/1,000 in FY1994 to a low of 3.2/1,000 in FY2011. ED visits and hospitalizations followed similar patterns of decreasing rates later in the study period. IRRs comparing the vaccine program versus pre-vaccine eras were 0.29 (95%CI: 0.26-0.32) for office visits, 0.29 (95%CI: 0.21-0.40) for ED visits, and 0.41 (95%CI: 0.10-1.69) for hospitalizations. Annual declines in varicella office visits were 7.7%, 9.1%, 8.4%, and 8.4% per year among children aged <1 year, 1-4 years, 5-11 years, and ≥12 years, respectively (all p<0.001). Age-specific rates of varicella-associated SSTI declined significantly among children <12 years (p<0.001) and rates of ICU admissions decreased significantly for children <1 year (p = 0.02). (p<0.001) over the study period. For children aged 5-17 years, herpes zoster office visits decreased whereas ED visits increased (both p<0.001) and there was a small, non-significant (p = 0.07), decrease in hospitalizations.

CONCLUSION

Medically-attended varicella decreased during the study period, particularly since varicella vaccine was publicly-funded. Results suggest immunization program-related changes in varicella epidemiology, including herd effects, demonstrated by reductions in varicella in program-ineligible age groups. We did not observe a consistent impact on herpes zoster.

Trends in medical and nonmedical immunization exemptions to measles-containing vaccine in Ontario: an annual cross-sectional assessment of students from school years 2002/03 to 2012/13

BACKGROUND

Under Ontario legislation, for select vaccine-preventable diseases nonimmunized or under-immunized students must undergo vaccination or provide a statement of exemption, or risk suspension from school. At the time of this assessment, these diseases included measles, mumps, rubella, diphtheria, tetanus and polio.

METHODS

Exemptions data for the school years 2002/03 to 2012/13 were obtained from the Immunization Records Information System used in Ontario. Temporal trends were expressed for 7- and 17-year-old students by exemption classification (medical, prior immunity, religious or conscientious belief, total) at the provincial level, by school year and by birth cohort. Regional analysis was conducted for the 2012/13 school year. A temporal trend analysis of exemptions for measles-containing vaccines was performed by using a Poisson distribution with a 2-sided test (α = 5%).

RESULTS

For both 7- and 17-year-old students, religious or conscientious exemptions for measles-containing vaccines significantly increased over the study period (p < 0.001 in both age groups), whereas medical exemptions decreased (p < 0.001 in both age groups). The trends were reproduced when examined by birth cohort. The percentage of Ontario students with any exemption classification (total exemptions) remained low (< 2.5%) during the study period, although considerable geographic variation was noted.

INTERPRETATION

Ontario data suggest that nonmedical exemptions have increased during the last 11 years, consistent with trends reported elsewhere. The trend toward increasing religious or conscientious exemptions coupled with declining medical exemptions explains why total exemptions have remained stable or decreased at the provincial level. The prominent geographic variability in exemptions suggests that targeted interventions may be suitable for consideration.

Improving vaccine registries through mobile technologies: a vision for mobile enhanced Immunization information systems

Immunization registries or information systems are critical to improving the quality and evaluating the ongoing success of immunization programs. However, the completeness of these systems is challenged by a myriad of factors including the fragmentation of vaccine administration, increasing mobility of individuals, new vaccine development, use of multiple products, and increasingly frequent changes in recommendations. Mobile technologies could offer a solution, which mitigates some of these challenges. Engaging individuals to have more control of their own immunization information using their mobile devices could improve the timeliness and accuracy of data in central immunization information systems. Other opportunities presented by mobile technologies that could be exploited to improve immunization information systems include mobile reporting of adverse events following immunization, the capacity to scan 2D barcodes, and enabling bidirectional communication between individuals and public health officials. Challenges to utilizing mobile solutions include ensuring privacy of data, access, and equity concerns, obtaining consent and ensuring adoption of technology at sufficiently high rates. By empowering individuals with their own health information, mobile technologies can also serve as a mechanism to transfer immunization information as individuals cross local, regional, and national borders. Ultimately, mobile enhanced immunization information systems can help realize the goal of the individual, the healthcare provider, and public health officials always having access to the same immunization information.

Understanding Public Perceptions of the HPV Vaccination Based on Online Comments to Canadian News Articles

BACKGROUND

Given the variation in human papillomavirus (HPV) vaccine coverage across Canada, and debate regarding delivery of HPV vaccines in Catholic schools, we studied online comments on Canadian news websites to understand public perceptions of HPV and HPV vaccine.

METHODS

We searched English- and French-language Canadian news websites for 2012 articles that contained the terms "HPV" or "human papillomavirus." Articles about HPV vaccinations that contained at least one comment were included. Two researchers independently coded comments, analyzing them for emerging themes.

RESULTS

We identified 3073 comments from 1198 individuals in response to 71 news articles; 630 (52.6%) individuals expressed positive sentiments about HPV vaccination (2.5 comments/individual), 404 (33.7%) were negative (3.0 comments/individual), 34 (2.8%) were mixed (1.5 comments/individual) and 130 (10.8%) were neutral (1.6 comments/individual). Vaccine-supportive commenters believed the vaccine is safe and effective. Common themes in negative comments included concerns regarding HPV vaccine safety and efficacy, distrust of pharmaceutical companies and government, and belief that school-age children are too young for HPV vaccine. Many comments focused on whether the Catholic Church has the right to inform health policy for students, and discussion often evolved into debates regarding HPV and sexual behaviour. We noted that many individuals doubted the credibility of vaccine safety information.

CONCLUSION

The majority of commenters do not appear to be against HPV vaccination, but public health messaging that focuses on both the vaccine's safety profile, and its use as a means to prevent cancer rather than sexually transmitted HPV infection may facilitate its acceptance.

Vaccine safety implications of Ontario, Canada's switch from DTaP-IPV to Tdap-IPV for the pre-school booster

Ontario, Canada, replaced the 4-6 year old diphtheria (D, d), tetanus (T), acellular pertussis (aP, ap) and polio (IPV) booster from DTaP-IPV to Tdap-IPV in May 2012. We assessed the impact of this replacement on the rate and types of reported adverse events following immunization (AEFIs). We used AEFIs reported among 4-6 years olds, through the provincial surveillance system, following administration of DTaP-IPV or Tdap-IPV from 2009 to 2013. Reporting rates per 100,000 doses distributed were calculated using publicly funded doses distributed as the denominator. A total of 204 AEFIs were reported (DTaP-IPV, n=182; Tdap-IPV, n=22). AEFI reporting rates were 33.1 and 6.3 per 100,000 doses distributed for DTaP-IPV and Tdap-IPV, respectively. Injection site reaction rate was lower for Tdap-IPV compared with DTaP-IPV (1.7 vs 20.6 per 100,000 doses). The replacement resulted in a decline in the number of reports and AEFI reporting rates, most notably a substantial decrease in injection site reactions.

Economic evaluation of meningococcal serogroup B childhood vaccination in Ontario, Canada

OBJECTIVE

Invasive Neisseria meningitidis serogroup B (MenB) disease is a low incidence but severe infection (mean annual incidence 0.19/100,000/year, case fatality 11%, major long-term sequelae 10%) in Ontario, Canada. This study assesses the cost-effectiveness of a novel MenB vaccine from the Ontario healthcare payer perspective.

METHODS

A Markov cohort model of invasive MenB disease based on high quality local data and data from the literature was developed. A 4-dose vaccination schedule, 97% coverage, 90% effectiveness, 66% strain coverage, 10-year duration of protection, and vaccine cost of C$75/dose were assumed. A hypothetical Ontario birth cohort (n=150,000) was simulated to estimate expected lifetime health outcomes, quality-adjusted life years (QALYs), and costs, discounted at 5%.

RESULTS

A MenB infant vaccination program is expected to prevent 4.6 invasive MenB disease cases over the lifetime of an Ontario birth cohort, equivalent to 10 QALYs gained. The estimated program cost of C$46.6 million per cohort (including C$318,383 for treatment of vaccine-associated adverse events) were not offset by healthcare cost savings of C$150,522 from preventing MenB cases, resulting in an incremental cost of C$4.76 million per QALY gained. Sensitivity analyses showed the findings to be robust.

CONCLUSIONS

An infant MenB vaccination program significantly exceeds commonly used cost-effectiveness thresholds and thus is unlikely to be considered economically attractive in Ontario and comparable jurisdictions.

A cocoon immunisation strategy against pertussis for infants: does it make sense for Ontario?

Pertussis deaths occur primarily among infants who have not been fully immunised. In Ontario, Canada, an adult booster dose was recently added to the publicly funded immunisation programme. We applied number-needed-to-treat analyses to estimate the number of adults that would need to be vaccinated (NNV) to prevent pertussis disease, hospitalisation and death among infants if a cocoon strategy were implemented. NNV=1/(P(M) X R) + 1/(P(F) X R), where P(M),P(F) (proportion of infants infected by mothers, fathers) were sourced from several studies. Rates of disease, hospitalisation or death (R) were derived from Ontario's reportable disease data and Discharge Abstract Database. After adjusting for under-reporting, the NNV to prevent one case, hospitalisation or death from pertussis was between 500-6,400, 12,000-63,000 and 1.1-12.8 million, respectively. Without adjustment, NNV increased to 5,000-60,000, 55,000-297,000 and 2.5-30.2 million, respectively. Rarer outcomes were associated with higher NNV. These analyses demonstrate the relative inefficiency of a cocoon strategy in Ontario, which has a well-established universal immunisation programme with relatively high coverage and low disease incidence. Other jurisdictions considering a cocoon programme should consider their local epidemiology.

Adverse events following immunization in Ontario's female school-based HPV program

BACKGROUND

In September 2007, a school-based human papillomavirus (HPV) vaccination program targeting grade 8 girls (approximately 13 years old) and delivered by public health was implemented in Ontario, Canada. We assessed reports of adverse events following immunization (AEFI) from the school-based program as part of quadrivalent HPV (HPV4) vaccine safety surveillance and to contribute to a comprehensive HPV vaccine program evaluation.

METHODS

AEFIs following HPV4 vaccine (Gardasil(®)) administered between September 1, 2007 and December 31, 2011 were extracted from the province's reportable disease system. Confirmed AEFI reports among females 12-15 years old (i.e. assumed to have received vaccine through the program) were included. Events were grouped according to provincial AEFI case definitions. Rates were calculated using doses distributed as the denominator.

RESULTS

Between 2007 and 2011, 133 confirmed AEFIs were reported while 691,994 HPV4 vaccine doses were distributed in the school-based program. The overall reporting rate was 19.2 HPV4 AEFI per 100,000 doses distributed. Annual reporting rates decreased from 30.0 to 18.3 per 100,000 doses distributed. Frequently reported events included 'allergic reaction-dermatologic/mucosa' (25%), 'rash' (22%), and 'local/injection site reaction' (20%); 26% of reports had a non-specific event of 'other severe/unusual events' selected. Ten serious AEFIs were reported (7.5% of reports) including 2 anaphylaxis, 2 seizures, 1 thrombocytopenia and 1 death. Further review found that the reports of anaphylaxis did not meet the Brighton anaphylaxis definition and the death was attributed to a preexisting cardiac condition.

CONCLUSIONS

Overall these findings are consistent with the safety profile of HPV4 vaccine from pre-licensure clinical trials and post-marketing surveillance reports and importantly, no new safety signals were identified, especially no reports of VTE in this younger female population. Continued assessment of HPV4 AEFI surveillance data may be important to detect and investigate safety signals.

Electronic immunization data collection systems: application of an evaluation framework

Background

Evaluating the features and performance of health information systems can serve to strengthen the systems themselves as well as to guide other organizations in the process of designing and implementing surveillance tools. We adapted an evaluation framework in order to assess electronic immunization data collection systems, and applied it in two Ontario public health units.

Methods

The Centers for Disease Control and Prevention’s Guidelines for Evaluating Public Health Surveillance Systems are broad in nature and serve as an organizational tool to guide the development of comprehensive evaluation materials. Based on these Guidelines, and informed by other evaluation resources and input from stakeholders in the public health community, we applied an evaluation framework to two examples of immunization data collection and examined several system attributes: simplicity, flexibility, data quality, timeliness, and acceptability. Data collection approaches included key informant interviews, logic and completeness assessments, client surveys, and on-site observations.

Results

Both evaluated systems allow high-quality immunization data to be collected, analyzed, and applied in a rapid fashion. However, neither system is currently able to link to other providers’ immunization data or provincial data sources, limiting the comprehensiveness of coverage assessments. We recommended that both organizations explore possibilities for external data linkage and collaborate with other jurisdictions to promote a provincial immunization repository or data sharing platform.

Conclusions

Electronic systems such as the ones described in this paper allow immunization data to be collected, analyzed, and applied in a rapid fashion, and represent the infostructure required to establish a population-based immunization registry, critical for comprehensively assessing vaccine coverage.

Association between birth order and emergency room visits and acute hospital admissions following pediatric vaccination: a self-controlled study

Objective

We investigated the association between a child's birth order and emergency room (ER) visits and hospital admissions following 2-,4-,6- and 12-month pediatric vaccinations.

Methods

We included all children born in Ontario between April 1^st, 2006 and March 31^st, 2009 who received a qualifying vaccination. We identified vaccinations, ER visits and admissions using health administrative data housed at the Institute for Clinical Evaluative Sciences. We used the self-controlled case series design to compare the relative incidence (RI) of events among 1^st-born and later-born children using relative incidence ratios (RIR).

Results

For the 2-month vaccination, the RIR for 1^st-borns versus later-born children was 1.37 (95% CI: 1.19–1.57), which translates to 112 additional events/100,000 vaccinated. For the 4-month vaccination, the RIR for 1^st-borns vs. later-borns was 1.70 (95% CI: 1.45–1.99), representing 157 additional events/100,000 vaccinated. At 6 months, the RIR for 1^st vs. later-borns was 1.27 (95% CI: 1.09–1.48), or 77 excess events/100,000 vaccinated. At the 12-month vaccination, the RIR was 1.11 (95% CI: 1.02–1.21), or 249 excess events/100,000 vaccinated.

Conclusions

Birth order is associated with increased incidence of ER visits and hospitalizations following vaccination in infancy. 1^st-born children had significantly higher relative incidence of events compared to later-born children.

Sociodemographic inequalities in sexual activity and cervical cancer screening: implications for the success of human papillomavirus vaccination

BACKGROUND

Papanicolaou smear screening has significantly reduced cervical cancer morbidity and mortality. However, inequalities still persist across different socioeconomic status (SES) groups. These inequalities have been associated with differential participation in screening. However, even with equal participation to screening, some women may still have greater risk of cervical cancer because of sexual behavior. We aim to identify the sociodemographic characteristics of women who reported greater sexual activity and/or screening underuse.

METHODS

We used data from (i) the Canadian Community Health Survey-2005, a population-based survey of 130,000 Canadians, and (ii) a multicenter study including 952 women screened for cervical cancer.

RESULTS

Aboriginals and women with lower SES reported greater sexual activity and lower screening participation, which may produce synergetic effects toward higher cervical cancer risk. Women who did not complete high school and aboriginals were, respectively, 3.6 and 2.5 times more likely to report sexual debut before 15 years old compared with women with university degree and Caucasians. Women who did not complete high school were 2.2 times more likely to have never been screened compared with women with university degree. East and South Asian women were, respectively, 4.3 and 3.1 times more likely to have never been screened than Canadian-born women but reported lower levels of sexual activity and were adherent to screening guidelines when screened at least once.

CONCLUSIONS

The success of human papillomavirus vaccination at reducing cervical cancer and inequalities will depend on achieving high coverage among high-risk subpopulations.

IMPACT

These groups must be monitored closely, and if need be, targeted for additional interventions.

Controlling serogroup B invasive meningococcal disease: the Canadian perspective

With publically funded meningococcal immunization programs established in infants, children and adolescents, Canada is at the forefront of invasive meningococcal disease prevention. The advent of two new serogroup B vaccines that may protect against multiple disease-causing strains offers the potential to reduce endemic disease to very low levels in Canada. Canada likely will be one of the first countries with approval to use recombinant serogroup B vaccine. However, inclusion of these new vaccines into public immunization programs will be decided at the provincial/territorial level, rather than nationally, and may result initially in different immunization schedules throughout the country as we have seen with conjugate meningococcal vaccines. Such heterogeneous use and adoption of new vaccines complicates disease control, but may assist in evaluation of effectiveness. Minimally, it requires regionally specific information. In this article, the authors provide an overview of the Canadian epidemiology, serogroup B vaccine characteristics, potential strain coverage, immunization strategies and remaining postmarketing research questions.