IMPACT after 17 years: Lessons learned about successful networking

A narrative review of vaccine pharmacovigilance during mass vaccination campaigns: Focus on myocarditis and pericarditis after COVID-19 mRNA vaccination

Vaccines have had a tremendous impact on reducing the burden of infectious diseases; however, they have the potential to cause adverse events following immunization (AEFIs). Prelicensure clinical trials are limited in their ability to detect rare AEFIs that may occur in less than one per thousand individuals. While postmarketing surveillance systems have shown COVID-19 mRNA vaccines to be safe, they led to the identification of rare cases of myocarditis and pericarditis after COVID-19 vaccination that were not initially detected in clinical trials. In this narrative review, we highlight concepts of vaccine pharmacovigilance during mass vaccination campaigns and compare the approaches used in the context of myocarditis and pericarditis following COVID-19 vaccination to historical examples. We describe mechanisms of passive and active surveillance, their strengths and limitations, and how they interacted to identify and characterize the safety signal of myocarditis and pericarditis after COVID-19 mRNA vaccination. Articles were synthesized from a PubMed search using relevant keywords for articles published on vaccine surveillance systems and myocarditis and pericarditis after COVID-19 vaccination, as well as the authors' collections of relevant publications and grey literature reports. The global experience around the identification and monitoring of myocarditis and pericarditis after COVID-19 mRNA vaccination has provided important lessons for vaccine safety surveillance and highlighted its importance in maintaining public trust in mass vaccination programmes in a pandemic context.

Comparing the Use of a Mobile App for Surveillance of Adverse Events Following Influenza Immunization to a Web-Based platform: a Randomized Controlled Trial (Preprint)

BACKGROUND

Vaccine safety surveillance is a core component of vaccine pharmacovigilance. In Canada, active, participant-centered vaccine surveillance is available for influenza vaccines and has been used for COVID-19 vaccines.

OBJECTIVE

The objective of this study is to evaluate the effectiveness and feasibility of using a mobile app for reporting participant-centered seasonal influenza adverse events following immunization (AEFIs) compared to a web-based notification system.

METHODS

Participants were randomized to influenza vaccine safety reporting via a mobile app or a web-based notification platform. All participants were invited to complete a user experience survey.

RESULTS

Among the 2408 randomized participants, 1319 (54%) completed their safety survey 1 week after vaccination, with a higher completion rate among the web-based notification platform users (767/1196, 64%) than among mobile app users (552/1212, 45%; P<.001). Ease-of-use ratings were high for the web-based notification platform users (99% strongly agree or agree) and 88.8% of them strongly agreed or agreed that the system made reporting AEFIs easier. Web-based notification platform users supported the statement that a web-based notification-only approach would make it easier for public health professionals to detect vaccine safety signals (91.4%, agreed or strongly agreed).

CONCLUSIONS

Participants in this study were significantly more likely to respond to a web-based safety survey rather than within a mobile app. These results suggest that mobile apps present an additional barrier for use compared to the web-based notification-only approach.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05794113; https://clinicaltrials.gov/show/NCT05794113.

The Canadian National Vaccine Safety Network: surveillance of adverse events following immunisation among individuals immunised with the COVID-19 vaccine, a cohort study in Canada

INTRODUCTION

COVID-19 vaccines require enhanced safety monitoring after emergency approval. The Canadian National Vaccine Safety Network monitors the safety of COVID-19 vaccines and provides enhanced monitoring for healthy, auto-immune, immunocompromised, pregnant and breastfeeding populations and allows for the detection of safety signals.

METHODS AND ANALYSIS

Online participant reporting of health events in vaccinated and unvaccinated individuals 12 years of age and older is captured in three surveys: 1 week after dose 1, 1 week after dose 2 and 7 months after dose 1. Medically attended events are followed up by telephone. The number, percentage, rate per 10 000 and incident rate ratios with 95% CIs are calculated by health event, vaccine type, sex and in 10-year age groups.

ETHICS AND DISSEMINATION

Each study site has Research Ethics Board approvals for the project (UBC Children's & Women's, CIUSSS de l'Estrie-CHUS, Health PEI, Conjoint Health Research Ethics Board, University of Calgary and Alberta Health Services, IWK Health, Unity Health Toronto and CHU de Québec-Université Laval Research Ethics Boards). Individuals are invited to participate in this active surveillance and electronic consent is given before proceeding to each survey. Weekly reports are shared with public health and posted on the study website. At least one peer-reviewed manuscript is produced.

2017/18 and 2018/19 seasonal influenza vaccine safety surveillance, Canadian National Vaccine Safety (CANVAS) Network

Background

The Canadian National Vaccine Safety (CANVAS) network monitors the safety of seasonal influenza vaccines in Canada.

Aim

To provide enhanced surveillance for seasonal influenza and pandemic influenza vaccines.

Methods

In 2017/18 and 2018/19 influenza seasons, adults (≥ 15 years of age) and parents of children vaccinated with the seasonal influenza vaccine participated in an observational study using web-based active surveillance. Participants completed an online survey for health events occurring in the first 7 days after vaccination. Participants who received the influenza vaccine in the previous season, but had not yet been vaccinated for the current season, were unvaccinated controls.

Results

In 2017/18, 43,751 participants and in 2018/19, 47,798 completed the online safety survey. In total, 957 of 30,173 participants vaccinated in 2017/18 (3.2%; 95% confidence interval (CI): 3.0–3.4) and 857 of 25,799 participants vaccinated in 2018/19 (3.3%; 95% CI: 3.1–3.5) reported a health problem of sufficient intensity to prevent their normal daily activities and/or cause them to seek medical care (including hospitalisation). This compared to 323 of 13,578 (2.4%; 95% CI: 2.1–2.6) and 544 of 21,999 (2.5%; 95% CI: 2.3–2.7) controls in each respective season. The event rate in vaccinated adults and children was higher than the background rate and was associated with specific influenza vaccines. The higher rate of events was associated with systemic symptoms and migraines/headaches.

Conclusion

In 2017/18 and 2018/19, higher rates of events were reported following seasonal influenza vaccination than in the pre-vaccination period. This signal was associated with several seasonal influenza vaccine products.

Estimated susceptibility of Canadian meningococcal B isolates to a meningococcal serogroup B vaccine (MenB-FHbp)

BACKGROUND

Invasive meningococcal disease caused by Neisseria meningitidis serogroup B (MenB) remains a health risk in Canada and globally. Two MenB vaccines are now approved for use. An understanding of the genotype of Canadian strains and the potential strain coverage conferred by the MenB-FHbp vaccine is needed to inform immunization policies.

METHODS

Serogroup B Neisseria meningitidis strains responsible for meningococcal disease in Canada from 2006 to 2012 were collected as part of the Canadian Immunization Monitoring Program Active surveillance network. Genotypic analysis was done on MenB isolates from 2006 to 2012 with determination of fHbp surface expression for a subset of isolates: those occurring from 2010 to 2012.

RESULTS

Two clonal complexes (cc269 and cc41/44) were observed in 68.8% of the 276 isolates. A total of 50 different fHbp peptides were identified among isolates from 2006 to 2012. Surface expression of fHbp was detected on 95% of MenB isolates from 2010 to 2012 and 91% of isolates expressed fHbp at levels that are predicted to be susceptible to the bactericidal immune response elicited by the MenB-FHbp vaccine. Some regional differences were observed, particularly in isolates from British Columbia and Quebec.

CONCLUSION

The majority of MenB isolates responsible for meningococcal disease in Canada expressed fHbp at levels predicted to be sufficient for complement mediated bactericidal activity in the presence of MenB-FHbp induced serum antibodies.

Proceedings of the Canadian Association for HIV Research: Canadian Foundation for Infectious Diseases Professional Development Workshop for Viral Researchers

In March 2018, the Canadian Association for HIV Research (CAHR) and Canadian Foundation for Infectious Diseases (CFID) collaborated to conduct a workshop targeted to mid-career virology researchers. Key objectives of the workshop included 1) sharing knowledge and expertise cutting across various viral diseases, 2) developing collaborations as we anticipate the next wave of suppressive and curative treatment for HIV, HBV, CMV, and other viral diseases, and 3) providing insights, advice, and "food for thought" as participants advance to mid- and later phases of their research careers. This article reports on the key topics contemplated including scientific misinformation within the public realm, network building, interdisciplinary collaboration, mentorship, and communicating with decision makers. Given the focus on virology, the Canadian Society for Virology was invited to highlight their efforts to build a cohesive network that is impactful in facilitating viral research in Canada including advocating for appropriate levels of peer-reviewed research funding. Many key pearls of wisdom are contained within this document which are of value to all researchers aiming for success in a continually evolving, complex, and challenging Canadian research and academic environment.

Building capacity for active surveillance of vaccine adverse events in the Americas: A hospital-based multi-country network

New vaccines designed to prevent diseases endemic in low and middle-income countries are being introduced without prior utilization in countries with robust vaccine pharmacovigilance systems. Our aim was to build capacity for active surveillance of vaccine adverse events in the Americas. We describe the implementation of a proof-of-concept study for the feasibility of an international collaborative hospital-based active surveillance system for vaccine safety. The study was developed and implemented in 15 sentinel sites located in seven countries of the region of the Americas, under the umbrella of the World Health Organization (WHO) Global Vaccine Safety Initiative. The study evaluated the associations between measles-mumps-rubella vaccines and two well-recognized adverse events: Immune thrombocytopenic purpura (ITP) and aseptic meningitis. The regional network contributed 63 confirmed ITP and 16 confirmed aseptic meningitis eligible cases to the global study, representing, respectively, 33% and 19% of the total cases. To ensure long-term sustainability and usefulness to investigate adverse events following new vaccine introductions in low and middle-income countries, the network needs to be strengthened with additional sites and integrated into national health systems.

Operational lessons learned in conducting a multi-country collaboration for vaccine safety signal verification and hypothesis testing: The global vaccine safety multi country collaboration initiative

Timely and effective evaluation of vaccine safety signals for newly developed vaccines introduced in low and middle- income countries (LMICs) is essential. The study tested the development of a global network of hospital-based sentinel sites for vaccine safety signal verification and hypothesis testing. Twenty-six sentinel sites in sixteen countries across all WHO regions participated, and 65% of the sites were from LMIC. We describe the process for the establishment and operationalization of such a network and the lessons learned in conducting a multi-country collaborative initiative. 24 out of the 26 sites successfully contributed data for the global analysis using standardised tools and procedures. Our study successfully confirmed the well-known risk estimates for the outcomes of interest. The main challenges faced by investigators were lack of adequate information in the medical records for case ascertainment and classification, and access to immunization data. The results suggest that sentinel hospitals intending to participate in vaccine safety studies strengthen their systems for discharge diagnosis coding, medical records and linkage to vaccination data. Our study confirms that a multi-country hospital-based network initiative for vaccine safety monitoring is feasible and demonstrates the validity and utility of large collaborative international studies to monitor the safety of new vaccines introduced in LMICs.

Canada's eight-component vaccine safety system: A primer for health care workers

Concerns about vaccine safety make some parents hesitant about immunization. Health care providers are pivotal in helping parents understand that Canada is a leader in vaccine safety. The present practice point provides an update on the eight components of Canada's vaccine safety system: (1) an evidence-based pre-license review and approval process; (2) strong regulations for manufacturers; (3) independent evidence-based vaccine use recommendations; (4) immunization competency training and standards for health care providers; (5) pharmacovigilance programs to detect and (6) determine causality of adverse events following immunization (AEFIs); (7) a program for vaccine safety and efficacy signal detection; and (8) the Canadian Immunization Research Network's special immunization clinics for children who have experienced serious AEFIs.

Hospitalization for Influenza A Versus B

BACKGROUND

The extent to which influenza A and B infection differs remains uncertain.

METHODS

Using active surveillance data from the Canadian Immunization Monitoring Program Active at 12 pediatric hospitals, we compared clinical characteristics and outcomes of children ≤16 years admitted with laboratory-confirmed influenza B or seasonal influenza A. We also examined factors associated with ICU admission in children hospitalized with influenza B.

RESULTS

Over 8 nonpandemic influenza seasons (2004-2013), we identified 1510 influenza B and 2645 influenza A cases; median ages were 3.9 and 2.0 years, respectively (P < .0001). Compared with influenza A patients, influenza B patients were more likely to have a vaccine-indicated condition (odds ratio [OR] = 1.30; 95% confidence interval [CI] = 1.14-1.47). Symptoms more often associated with influenza B were headache, abdominal pain, and myalgia (P < .0001 for all symptoms after adjustment for age and health status). The proportion of deaths attributable to influenza was significantly greater for influenza B (1.1%) than influenza A (0.4%); adjusted for age and health status, OR was 2.65 (95% CI = 1.18-5.94). A similar adjusted OR was obtained for all-cause mortality (OR = 2.95; 95% CI = 1.34-6.49). Among healthy children with influenza B, age ≥10 years (relative to <6 months) was associated with the greatest odds of ICU admission (OR = 5.79; 95% CI = 1.91-17.57).

CONCLUSIONS

Mortality associated with pediatric influenza B infection was greater than that of influenza A. Among healthy children hosptialized with influenza B, those 10 years and older had a significant risk of ICU admission.

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 Canadian Immunization Monitoring Program, ACTive (IMPACT): Active surveillance for vaccine adverse events and vaccine-preventable diseases

For almost 25 years the Canadian Immunization Monitoring Program, ACTive (IMPACT) has been conducting active surveillance for severe adverse events following immunization (AEFIs) and vaccine-preventable diseases in children. The network, which consists of volunteer paediatric infectious diseases investigators at 12 tertiary care paediatric hospitals, is an important component of Canada's AEFI monitoring. The network employs nurses at each of the sites to search for and report possible AEFIs to local, provincial and national public health authorities. The active nature of the surveillance ensures a high level of vigilance for severe AEFIs in children.

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.

Paediatric active enhanced disease surveillance: a new surveillance system for Australia

AIM

The Paediatric Active Enhanced Disease Surveillance (PAEDS) is described. PAEDS is active in four tertiary children's hospitals in four states of Australia and aims to address gaps in surveillance for severe vaccine-preventable diseases and adverse events following immunisation.

METHODS

From August 2007 to December 2010, surveillance nurses actively identified and recruited children admitted with: acute flaccid paralysis, varicella infection, intussusception, seizures in infants and pandemic influenza (June-October 2009). Details of presentation, medical and immunisation history, outcome and laboratory results were collected. Completeness of ascertainment was estimated through audits of International Classification of Diseases 10th edition-coded medical records where possible.

RESULTS

Seven hundred thirty-three cases matching case definition criteria for the four conditions were recruited. In addition, 601 cases of influenza were recruited during the 2009 pandemic. PAEDS enhanced acute flaccid paralysis surveillance by the Australian Paediatric Surveillance Unit; the World Health Organization surveillance target was met when Australian Paediatric Surveillance Unit and PAEDS cases were combined. Among 133 children hospitalised for varicella, only 16 were vaccinated; samples of vesicle scrapings were collected in 57% for genotyping. Of 122 infants presenting with seizures, only six (12%) had received a vaccine in the last 7 days. Intussusception was more frequent among infants receiving their first dose of either of the rotavirus vaccines. Results informed policy and education for parents and health professionals. Preliminary audits of medical records suggest excellent ascertainment through PAEDS.

CONCLUSIONS

PAEDS provides important, previously unavailable data to inform public health policy, clinical practice and community confidence. It has potential to respond quickly during outbreaks and epidemics.

Cost effectiveness of infant vaccination for rotavirus in Canada

INTRODUCTION

Rotavirus is the main cause of gastroenteritis in Canadian children younger than five years of age, resulting in significant morbidity and cost. The present study provides evidence on the cost effectiveness of two alternative rotavirus vaccinations (RotaTeq [Merck Frosst Canada Ltd, Canada] and Rotarix [GlaxoSmithKline, Canada]) available in Canada.

METHODS

Analysis was conducted through a Markov model that followed a cohort of children from birth to five years of age. Analysis used pertinent data on the natural history of rotavirus and the effects of vaccination. Estimates of heath care costs for children requiring hospitalizations and emergency department visits were derived from the Canadian Immunization Monitoring Program, Active (IMPACT) surveillance, emergency department studies, as well as other Canadian studies. The model estimated the effect of vaccination on costs and quality-adjusted life years (QALYs).

RESULTS

The incremental cost per QALY gained from the health care system perspective was $122,000 for RotaTeq and $108,000 for Rotarix. From the societal perspective, both vaccination strategies were dominant - both cost saving and more effective. The cost-effectiveness of vaccination is dependent on the mode of administration, the perspective adopted and the cost of the vaccine.

CONCLUSIONS

From a societal perspective, a universal vaccination program against rotavirus will be both cost saving and more effective than no vaccination. Becasue the majority of rotavirus infections do not require emergency department visits or hospital admission, from a health care system perspective, a program would not be considered cost effective.

The disease burden of invasive meningococcal serogroup B disease in Canada

BACKGROUND

Invasive meningococcal disease remains a rare but deadly infection in Canada. New serogroup B vaccines may offer the potential for prevention and control. This report examines the disease burden caused by serogroup B invasive meningococcal infections.

METHODS

From 2002 to 2011, active, population-based metropolitan area surveillance for adult and pediatric hospital admissions for adult and pediatric hospital admissions for laboratory-confirmed infection with Neisseria meningitidis, was conducted by the 12 centers of the Canadian Immunization Monitoring Program, Active.

RESULTS

A total of 769 invasive meningococcal cases occurred from 2002 to 2011; 54% (n = 413) in children with a peak incidence of 6.16 (95% confidence interval: 3.18-10.76) per 100,000 in children aged <1 year in 2009. Serogroup B accounted for the largest proportion of cases and had the highest incidence of all serogroups across all ages, with a peak incidence of 0.31 (0.23-0.40) per 100,000 in 2007. Serogroup B case fatality rate was 4.3% in children, and 21% of pediatric survivors had sequelae. B:17:P1.19 ST-269 was the most frequently detected antigenic type.

CONCLUSIONS

Serogroup B invasive meningococcal infections caused substantial morbidity and mortality and are the leading cause of invasive meningococcal disease in Canada. The proportion of cases potentially preventable with the new serogroup B vaccines should be evaluated to determine whether universal immunization programs are warranted.

Comparison of children hospitalized with seasonal versus pandemic influenza A, 2004-2009

BACKGROUND

The extent to which pandemic H1N1 influenza (pH1N1) differed from seasonal influenza remains uncertain.

METHODS

By using active surveillance data collected by the Immunization Monitoring Program, Active at 12 Canadian pediatric hospitals, we compared characteristics of hospitalized children with pH1N1 with those with seasonal influenza A. We compared demographics, underlying health status, ICU admission, and mortality during both pandemic waves versus the 2004/2005 through the 2008/2009 seasons; influenza-related complications and hospitalization duration during pH1N1 wave 1 versus the 2004/2005 through the 2008/2009 seasons; and presenting signs and symptoms during both pH1N1 waves versus the 2006/2007 through the 2008/2009 seasons.

RESULTS

We identified 1265 pH1N1 cases (351 in wave 1, 914 in wave 2) and 1319 seasonal influenza A cases (816 from 2006/2007 through 2008/2009). Median ages were 4.8 (pH1N1) and 1.7 years (seasonal influenza A); P < .0001. Preexisting asthma was overrepresented in pH1N1 relative to seasonal influenza A (13.8% vs 5.5%; adjusted P < .0001). Symptoms more often associated with pH1N1 wave 1 versus seasonal influenza A were cough, headache, and gastrointestinal symptoms (adjusted P < .01 for each symptom). pH1N1 wave 1 cases were more likely to have radiologically confirmed pneumonia (adjusted odds ratio = 2.1; 95% confidence interval = 1.1-3.8) and longer median length of hospital stay (4 vs 3 days; adjusted P = .003) than seasonal influenza A. Proportions of children requiring intensive care and deaths in both pH1N1 waves (14.6% and 0.6%, respectively) were not significantly different from the seasonal influenza A group (12.7% and 0.5%, respectively).

CONCLUSIONS

pH1N1 in children differed from seasonal influenza A in risk factors, clinical presentation, and length of hospital stay, but not ICU admission or mortality.

The effect of funded varicella immunization programs on varicella-related hospitalizations in IMPACT centers, Canada, 2000-2008

BACKGROUND

The 12 Immunization Monitoring Program, Active (IMPACT) centers that represent 90% of pediatric tertiary care beds in Canada conducted active surveillance for varicella-related hospitalizations and complications from 1999 onward, after varicella vaccine was authorized. Publicly funded routine immunization programs at 12 or 15 months of age were introduced by 5 provinces and territories (prov/terr) in 2000 to 2002 (earlier programs, EP) and by 8 prov/terr in 2004 to 2007 (later programs, LP).

OBJECTIVE

To determine whether the number of varicella-related hospitalized cases had declined by 2008 at 12 IMPACT centers after the sequential introduction of publicly funded varicella immunization programs in Canada.

METHODS

Varicella-related hospitalizations from 2000 to 2008 in the prov/terr with EP were under surveillance by 3 IMPACT centers (Halifax, Edmonton, Calgary), whereas the prov/terr with LP were under surveillance by the remaining 9 centers. The age, gender, underlying health status, varicella complications, and length of stay in hospital and the pediatric intensive care unit were documented. Breakthrough cases were identified and their clinical characteristics described.

RESULTS

Between 2000 and 2008, the number of varicella-related hospitalized cases in IMPACT centers declined relatively sooner in prov/terr with EP (by 2002 to 2003), as compared to those with LP (only by 2007 to 2008). In 2008, varicella-related hospitalized cases declined by 88% in the EP centers, and by 81% in the LP centers. In all IMPACT centers, the greatest decline occurred in the 1-4 years age group (90% decline), with smaller declines in both <1 year and 5-9 years age groups (78% and 76% decline, respectively). Breakthrough disease accounted for 39 (2%) cases, with the proportion due to breakthrough increasing from 0.9% in 2000 to 2001, to 2% in 2003 to 2004 and 9.5% in 2007 to 2008. The majority (72%) of breakthrough cases were in immunocompromised children.

CONCLUSIONS

Publicly funded varicella vaccination programs have led to a significant decline in varicella-related hospitalizations in Canadian children, as a result of direct effects of the program beginning within 1 to 2 years after the start, as well as probable indirect protection of children outside the vaccinated cohort.

Heterogeneity of rotavirus testing and admitting practices for gastroenteritis among 12 tertiary care pediatric hospitals: Implications for surveillance

BACKGROUND

The Canadian Immunization Monitoring Program, ACTive (IMPACT) surveillance for rotavirus relies on monitoring hospital admissions. Because a diagnosis of rotavirus is not necessary for treatment purposes, and rotavirus is not a reportable disease, wide variation may exist in the admitting and testing practices for this disease. From 2005 to 2007, the number of rotavirus admissions differed significantly among IMPACT centres, and this variation could not be explained by population differences alone. Understanding this variation is important when interpreting surveillance data and estimating the cost-effectiveness of rotavirus vaccination programs.

METHODS

Key informant interviews were conducted with pediatric infectious disease physicians and IMPACT nurse monitors involved with rotavirus surveillance to obtain in-depth information about rotavirus testing and admitting practices at each of the 12 IMPACT centres.

RESULTS

A total of 18 of 24 interviews were completed, with at least one interview conducted with physicians and/or nurses at each centre. Four major differences were identified among the centres: case-identification methods, admission definitions, admission criteria and testing criteria. The criteria for admitting and testing patients as well as which patients were defined as admissions had the greatest influence on case totals.

DISCUSSION

The present study found that differences in admitting and testing practices may contribute to significant differences in rotavirus admission totals. Given these differences, caution should be used when using local case estimates for cost-effectiveness analyses and immunization program decisions. The present study illustrates that understanding the factors that influence the identification of a disease is important when interpreting and applying surveillance data.

The changing and dynamic epidemiology of meningococcal disease

The epidemiology of invasive meningococcal disease continues to change rapidly, even in the three years since the first Meningococcal Exchange Meeting in 2008. Control of disease caused by serogroup C has been achieved in countries that have implemented meningococcal C or quadrivalent meningococcal ACWY conjugate vaccines. Initiation of mass immunization programs with meningococcal A conjugate vaccines across the meningitis belt of Africa may lead to the interruption of cyclical meningococcal epidemics. A meningococcal B vaccination program in New Zealand has led to a decreased incidence of high rates of endemic serogroup B disease. Increases in serogroup Y disease have been observed in certain Nordic countries which, if they persist, may require consideration of use of a multiple serogroup vaccine. The imminent availability of recombinant broadly protective serogroup B vaccines may provide the tools for further control of invasive meningococcal disease in areas where serogroup B disease predominates. Continued surveillance of meningococcal disease is essential; ongoing global efforts to improve the completeness of reporting are required.

Substantial morbidity for hospitalized children with community-acquired rotavirus infections: 2005-2007 IMPACT surveillance in Canadian hospitals

We describe community-acquired rotavirus illness in 1359 children hospitalized at 12 centers in Canada between January 2005 and December 2007. The median age was 1.5 years. Almost half (48.6%) had significant dehydration, almost one-fifth (19%) had clinical sepsis and 7% had seizures at presentation. The median hospital stay was 3.4 days. Severe clinical presentations are less commonly described in surveillance programs.