Immunization Monitoring Program Active Research Articles

Applicability of the Brighton Collaboration Case Definition for seizure after immunization in active and passive surveillance in Canada

BackgroundThe Canadian Adverse Event Following Immunization Surveillance System (CAEFISS) receives reports via active syndromic surveillance for selected serious AEFI from the Canadian Immunization Monitoring Program Active (IMPACT) and via targeted passive surveillance from Federal/Provincial/Territorial health jurisdictions. Post-immunization seizure is a target of active and passive surveillance. Since 2009, the revised national AEFI reporting forms enable capture of terms specific to several Brighton Collaboration Case Definitions (BCCD) including generalized seizure and fever. ObjectiveTo evaluate feasibility of applying the BCCD for generalized seizure to adverse event following immunization (AEFI) reports collected by IMPACT and targeted passive surveillance (non-IMPACT). MethodsReports to CAEFISS coded as seizure in children <2 years of age (vaccination dates 1998–2011) were reviewed retrospectively. A BCCD level (1–5 or unclassifiable) was assigned. The effects of reporting source (IMPACT versus non-IMPACT), seriousness [serious (e.g., hospitalized) versus non-serious], vaccination year (1998–2008 versus 2009–2011), and data submission method to CAEFISS (electronic versus paper) were assessed by stratified analysis. ResultsThere were 459 IMPACT and 908 non-IMPACT cases analyzed, of which 99.6% and 27%, respectively, were serious reports. The revised reporting form that captured the BCCD components (2009–2011) was associated with increased proportions of IMPACT and non-IMPACT cases meeting the BCCD for generalized seizure. ConclusionsIncorporating the BCCD components (level of consciousness, motor manifestations and fever ≥38°C) into the national reporting form and guidelines appeared to improve the feasibility of their use in AEFI surveillance. This effect was more pronounced among active syndromic surveillance compared to targeted passive surveillance reports.

Diversity of Canadian meningococcal serogroup B isolates and estimated coverage by an investigational meningococcal serogroup B vaccine (4CMenB)

BackgroundIn collaboration with the Canadian Immunization Monitoring Program Active (IMPACT), the National Microbiology Laboratory, the UK Health Protection Agency and Novartis Vaccines, we tested the potential of an investigational 4-component meningococcal B vaccine (4CMenB) to cover Canadian strains circulating from 2006 to 2009. MethodsIMPACT meningococcal surveillance is population based and includes over 50% of Canadian adults and children. All isolates were characterized by Meningococcal Antigen Typing System (MATS) and sequencing for factor H-binding protein (fHbp), Neisseria Heparin Binding Antigen (NHBA) and Neisserial adhesin A (NadA). ResultsIn total, 157 isolates were tested. Overall, 4CMenB MATS predicted strain coverage was 66% (95% CI: 46–78%), with 26%, 29% and 11% of strains covered by one, two and three vaccine antigens, respectively. The coverage of each antigen was as follows: 13% PorA, 1% NadA, 52% fHbp and 51% NHBA. The majority of strains for clonal complex (cc) 41/44 and cc60 were covered by NHBA; the majority of strains for cc269 and cc32 were covered by fHbp and NHBA.Coverage for two prevalent strains (sequence type (ST)-269 and ST-154) was 95% and 100%, respectively. Conclusions4CMenB has the potential to protect against a significant proportion of Canadian invasive MenB strains.

The Effect of Funded Varicella Immunization Programs on Varicella-related Hospitalizations in IMPACT Centers, Canada, 2000–2008

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). 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. 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. 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. 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.

Cost Effectiveness of Infant Vaccination for Rotavirus in Canada

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. 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). 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. 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.

Heterogeneity of Rotavirus Testing and Admitting Practices for Gastroenteritis among 12 Tertiary Care Pediatric Hospitals: Implications for Surveillance

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. 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. 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. 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.

Respiratory distress and the flu: What should a physician know?

A five-year-old girl, with known thalassemia, presented in September 2009 with a history of 36 h of fever, runny nose, sore throat, lack of appetite and cough. She had vomited a few times and had watery bowel movements. Because of increasing cough, shortness of breath and lethargy, she was brought to the emergency department by her parents, who were also not feeling well. On arrival, her temperature was 39.5°C and her respiratory rate was 60 breaths/min. She looked pale and her oxygen saturation was 90% in room air. On auscultation, crackles were heard and her chest radiograph confirmed pneumonia in the right middle and right lower lobes. In view of her acute respiratory presentation, she was immediately isolated with contact and droplet precautions. Blood culture was drawn and a nasopharyngeal aspirate was sent for respiratory viruses. She was started empirically on an intravenous antibiotic and oseltamivir (45 mg orally twice daily), while awaiting laboratory confirmation of the diagnosis. She rapidly deteriorated with desaturation on a fraction of inspired oxygen of 100%, and was transferred to a paediatric intensive care unit (PICU) where she was intubated and required mechanical ventilation. Later that day, a reverse transcription polymerase chain reaction for pandemic influenza A (H1N1) was reported as positive. Her PICU stay was prolonged and she received a full course of oseltamivir. The antibiotics were also continued because of the risk of bacterial coinfection in this very ill child. She slowly improved and was successfully weaned off the respirator. The child was discharged home 10 days after her initial presentation. No family members developed symptoms and because of the early institution of appropriate infection control measures, other high-risk children in the PICU were protected from nosocomial infection. LEARNING POINTS In early April 2009, a pandemic H1N1 influenza A virus was reported to cause respiratory distress in humans and rapidly spread to reach pandemic proportion. As of the end of August 2009, 327 paediatric hospitalizations for influenza had been reported since April 26, 2009; 99.4% of these hospitalizations were due to pandemic (H1N1) 2009. To date, for the entire 2008 to 2009 influenza season, 738 paediatric hospitalizations and five deaths have been reported. Three of the deaths were due to pandemic (H1N1) 2009 (1). Antiviral therapy is recommended for children and youth only when their influenza illness is severe enough to warrant hospitalization or when their underlying conditions predispose them to serious illness. Susceptibility to antiviral medications, such as oseltamivir, zanamivir, amantadine and rimantadine, varies from strain to strain of influenza and can change. At present, the pandemic strain of H1N1 is susceptible to oseltamivir and zanamivir, but the seasonal H1N1 is resistant to oseltamivir. Current resistance patterns should be consulted when choosing an antiviral agent for a sick child. There is limited information on adverse events associated with the use of an antiviral agent in children (2,3). Health Canada has issued interim approval for the emergency use of oseltamivir in children younger than one year of age, given their increased risk for morbidity and mortality from influenza (4). Patients with severe influenza requiring hospitalization may have bacterial pneumonia as a coinfection. Thus, it is important to treat such patients with both empirical antibacterial therapy and antiviral medications (5). Physicians are reminded not to use acetylsalicylic acid or medications containing salicylates in patients with influenza symptoms because of the risk of Reye’s syndrome. Acetaminophen and ibuprofen are preferred. A rare complication of influenza infections is Guillain-Barre syndrome, and not surprisingly, cases have been reported with the pandemic H1N1 influenza A strain. Surveillance is an essential tool to provide real-time national data to public health policy makers on the infectious disease itself and on the adverse drug reactions (ADRs) potentially associated with specific treatments. ○ The Canadian Immunization Monitoring Program, ACTive (IMPACT) is a paediatric hospital-based national active surveillance network looking for cases of vaccine-preventable infectious diseases such as influenza, in 12 paediatric centres across Canada. The network continues to make surveillance of H1N1 influenza A a high priority as the pandemic unfolds, to provide a complete and accurate description of the most severely affected children and youth in Canada (6). ○ The Canadian Paediatric Surveillance Program (CPSP) is a network of more than 2500 actively practicing paediatricians who report monthly on diseases with high burden and on serious ADRs. The CPSP continues to monitor ADRs related to antiviral drugs (7). With increasing use of antiviral drugs, physicians should watch for ADRs and report them promptly to the CPSP and Health Canada.

The Impact of Childhood Meningococcal Serogroup C Conjugate Vaccine Programs in Canada

Conjugate meningococcal vaccines may decrease the incidence of disease. The staggered implementation of universal childhood meningococcal C conjugate (MenC) immunization programs across Canada offers an opportunity to evaluate the influence of these programs. From 2002 to 2006, we conducted active, population-based surveillance for adult and pediatric hospital admissions related to meningococcal infections at the 12 centers of the Canadian Immunization Monitoring Program, Active (IMPACT), in collaboration with local public health officials. A total of 376 cases were reported during the 5 years of surveillance. Yearly totals were as follows: 96 in 2002, 73 in 2003, 81 in 2004, 58 in 2005, and 68 in 2006. Case fatality was 9.3% and adults had a significantly higher case fatality rate than children.Average incidence per 100,000 was 0.62 (95% confidence interval [CI]: 0.50-0.76) in 2002 and 0.42 (95% CI: 0.32-0.53) in 2006. The highest rates were in children age 0 to 4 years, followed by adolescents age 15 to 19 years. Incidence of group C disease decreased significantly during the 5 years from 0.23 (95% CI: 0.16-0.32) in 2002 to 0.08 (95% CI: 0.04-0.14) in 2006, whereas incidence remained stable for groups B, Y, and W135. The decrease in group C disease was seen in provinces that first implemented MenC immunization programs. A substantial decrease in group C incidence occurred in provinces with early MenC immunization programs. Serogroup C incidence remained stable in provinces without MenC programs. We found no evidence of serogroup replacement.

Do childhood vaccines cause thrombocytopenia?

Do childhood vaccines cause thrombocytopenia?

Children hospitalized with influenza during the 2006-2007 season: a report from the Canadian Immunization Monitoring Program, Active (IMPACT).

Children hospitalized with influenza during the 2006-2007 season: a report from the Canadian Immunization Monitoring Program, Active (IMPACT).

The Epidemiology of Children Hospitalized With Herpes Zoster in Canada

Varicella zoster virus causes varicella (chickenpox) and can reactivate to cause herpes zoster (HZ). In Canada, live attenuated varicella vaccine was recommended for routine use among healthy susceptible children age 1 year and older, in 1999. Varicella vaccine has had a profound impact on the incidence of varicella; however the impact on HZ remains uncertain. Surveillance for HZ admissions was conducted by the Immunization Monitoring Program, Active (IMPACT) surveillance network comprising 12 centers representing over 90% of pediatric tertiary care beds in Canada. Active surveillance for HZ was undertaken in 1991-1996 and reintroduced in 1999. A clinical diagnosis was accepted, with or without laboratory confirmation. For each case, a detailed case report form was completed. In total, 648 children were admitted with HZ; 342 (52.8%) were boys and the mean age was 9.9 +/- 4.4 years. Five hundred seventy-seven (89.0%) were immunocompromised and 71 immunocompetent (10.8%). Five hundred seventy-one (88.1%) had a history of varicella zoster virus infection. Varicella vaccination was documented in 4 children before admission. Most (85.5%) presented with localized disease. Immunocompetent children were more likely than immunocompromised children to be hospitalized with ophthalmic disease (odds ratio 5.1, P < 0.001) or with at least 1 complication (odds ratio 3.0, P < 0.001). Only 1 death was attributable to HZ. Immunocompromised children represented the overwhelming majority of IMPACT hospitalized cases. Complications directly resulting from HZ were common in immunocompetent children. As varicella vaccine use becomes more widespread, the IMPACT network will continue to play an important role in monitoring the changing epidemiology of HZ in children.

Invasive Infections Caused by Haemophilus influenzae Serotypes in Twelve Canadian IMPACT Centers, 1996–2001

Haemophilus influenzae type b (Hib) immunization has changed the epidemiology of pediatric bacterial invasive disease. We describe the epidemiology of H. influenzae invasive infections in 12 Canadian pediatric tertiary care [Immunization Monitoring Program, ACTive (IMPACT)] centers during the era of universal immunization against this pathogen. Children with positive cultures for H. influenzae serotypes a to f (Hia to Hif) and nontypable H. influenzae from sterile sites were identified from the laboratory records at 12 IMPACT centers from January 1, 1996 to December 31, 2001. Hospital records were retrospectively reviewed for demographic and clinical information. Of 166 H. influenzae cases, 58 (35%) were caused by Hib, 89 (54%) by non-b serotypes, and 19 (11%) were not serotyped. The non-b serotypes included: 25 Hia (28%), 4 Hid (4%), 2 Hie (2%), 11 Hif (12%), and 47 were nontypable isolates (53%). For patients with Hib and Hia infection, meningitis was the most common presentation, accounting for 40% and 52% respectively, whereas the most common presentation for nontypable serotypes was pneumonia, seen in 43% of cases. Epiglottitis was associated mainly with Hib. Aboriginal ethnicity was an important risk factor for Hia cases, accounting for 76% of patients with infections caused by this serotype. Mean duration of hospitalization, need for admission to a pediatric intensive care unit, and case fatality rates were similar for the cases because of Hib, Hia, Hif, and nontypable serotypes. In 1996-2001, two-thirds of H. influenzae invasive disease in the 12 IMPACT centers was caused by non-b serotypes, which were associated with significant morbidity and mortality.

Invasive pneumococcal infections in Canadian children, 1998-2003: implications for new vaccination programs.

We conducted active surveillance for invasive pneumococcal disease to assess the serotype and antibiotic resistance patterns in Canada prior to universal infant immunization programs, in most provinces. Active surveillance was conducted by the 12 centres of the Canadian Paediatric Society's Immunization Monitoring Program, Active (IMPACT). This report includes children 16 years of age and younger with S. pneumoniae isolated from a normally sterile site, in 1998-2003. During six years of surveillance, 1,868 eligible cases were reported. The 7-valent pneumococcal conjugate vaccine (PCV7) matched 79% of isolates, including 84% from 6-23 month olds and 80% from 2-5 year olds. The proportion of isolates matched by PCV7 significantly decreased over the surveillance period from 81% in 1998 to 73% in 2003 (p = 0.005). The 23-valent polysaccharide vaccine (PPS) matched 90% of isolates from children 2 years or older. Penicillin non-susceptibility rate was stable at 16% of isolates. Cefotaxime/ceftriaxone resistance rate was 5% and limited to penicillin-resistant isolates. Serotypes found in PCV7 accounted for 89% of penicillin-resistant isolates (100% including cross-reacting types 6A and 19A). PCV7 matched three quarters of the isolates from young children as immunization programs began; therefore some program failures are inevitable. Children > or =5 years with predisposing conditions need the broader protection of 23-valent PPS vaccine and special attention from providers to ensure receipt. The rate of penicillin resistance remained steady over the last six years. The majority of isolates non-susceptible to penicillin are found in PCV7.

Invasive Pneumococcal Infections in Canadian Children, 1998–2003 Implications for New Vaccination Programs

We conducted active surveillance for invasive pneumococcal disease to assess the serotype and antibiotic resistance patterns in Canada prior to universal infant immunization programs, in most provinces. Active surveillance was conducted by the 12 centres of the Canadian Paediatric Society’s Immunization Monitoring Program, Active (IMPACT). This report includes children 16 years of age and younger with S. pneumoniae isolated from a normally sterile site, in 1998–2003. During six years of surveillance, 1,868 eligible cases were reported. The 7-valent pneumococcal conjugate vaccine (PCV7) matched 79% of isolates, including 84% from 6–23 month olds and 80% from 2–5 year olds. The proportion of isolates matched by PCV7 significantly decreased over the surveillance period from 81% in 1998 to 73% in 2003 (p=0.005). The 23-valent polysaccharide vaccine (PPS) matched 90% of isolates from children 2 years or older. Penicillin non-susceptibility rate was stable at 16% of isolates. Cefotaxime/ceftriaxone resistance rate was 5% and limited to penicillin-resistant isolates. Serotypes found in PCV7 accounted for 89% of penicillin-resistant isolates (100% including cross-reacting types 6A and 19A). PCV7 matched three quarters of the isolates from young children as immunization programs began; therefore some program failures are inevitable. Children ≥5 years with predisposing conditions need the broader protection of 23-valent PPS vaccine and special attention from providers to ensure receipt. The rate of penicillin resistance remained steady over the last six years. The majority of isolates non-susceptible to penicillin are found in PCV7.

The Effect of Changing From Whole-Cell to Acellular Pertussis Vaccine on the Epidemiology of Hospitalized Children With Pertussis in Canada

Between July 1997 and April 1998, universal childhood immunization programs in Canada changed from using a whole-cell pertussis to a 5-component acellular pertussis-containing vaccine. To assess effects on pertussis epidemiology of this nationwide change, we analyzed hospitalizations during 1991-2004 using the Canadian Immunization Monitoring Program, Active (IMPACT) pertussis database. IMPACT is an active surveillance network based in 12 pediatric tertiary-care hospitals across Canada. Characteristics of hospitalized cases of pertussis were compared by type of vaccine received or by birth date (if immunization records were unavailable or the child was unvaccinated). Age-stratified incidence rates were calculated by year and vaccine type. Two thousand ninety-six cases of pertussis were admitted to IMPACT centers, 1174 during the whole-cell vaccine program (WCV-P) and 842 during the acellular vaccine program (ACV-P). Pertussis incidence among children <5 years old decreased significantly during the ACV-P, causing an increase in the residual proportion of cases either too young to be immunized (<2 months old: ACV-P 39% versus WCV-P 26.1%; P < 0.0001) or too young for a second dose (2-3 months old: 42.9% versus 34.2%, respectively; P < 0.0001). A significantly smaller proportion of cases (ACV-P 15.1% versus WCV-P 27.3%) occurred in infants who were old enough (4-11 months of age) to have received 2 or 3 doses of vaccine. With ACV-P, pertussis hospitalizations in children 4-59 months old decreased in frequency, consistent with improved vaccine effectiveness, but remained prominent among very young infants. Improved control strategies are needed to reduce infections among infants too young for pertussis vaccination.

Seven fatal varicella infections in children were potentially avoidable: A report from IMPACT centres from 2000 to 2005

A varicella vaccine for children has been readily available in Canada since 2000, but some parents and physicians doubt the need for it. The Immunization Monitoring Program, ACTive (IMPACT) network of pediatric hospitals tabulated 1900 varicella-related hospitalizations and seven varicella-related deaths from 2000 to 2005. The present report describes these fatal cases, demonstrating the unpredictable and avoidable nature of life-threatening varicella complications. The knowledge that healthy children can die of chickenpox could influence parents to accept the recommended vaccination. Deaths from varicella should cease to occur, given the safe alternative of, and free access to, vaccination in current provincial programs.

Serious Adverse Events Associated with Bacille Calmette-Guérin Vaccine in Canada

Targeted Bacille Calmette-Guérin (BCG) vaccination is offered to neonates in some First Nations and Inuit (FNI) communities in Canada. Serious adverse events associated with BCG vaccine prompted a review to assess causality. The Immunization Monitoring Program Active (IMPACT), a pediatric hospital-based active surveillance network, reported admissions for BCG-related adverse events between 1993 and April 2002. The Canadian Advisory Committee on Causality Assessment (ACCA) reviewed the reports to assess causality. Data between 1987 and September 2002 from the Vaccine-Associated Adverse Event Surveillance (VAAES) Program, a passive national reporting system, were also reviewed. IMPACT identified 21 pediatric cases; 19 were Canadian-born, and 18 were FNI. Six disseminated BCG cases were identified; 5 were FNI infants who subsequently died. All had immunodeficiencies and concurrent infections. Other adverse events included 2 cases of osteomyelitis, BCG abscesses and lymphadenitis. ACCA reviewed the 21 cases and determined that 14 were very likely associated with the vaccine, including the 6 disseminated BCGs; 5 were probably associated and 1 was possibly associated with the vaccine; 1 was unclassifiable. The VAAES program identified 157 adverse events. No additional serious systemic adverse events (disseminated BCG or osteomyelitis) were identified. Serious BCG vaccine-associated complications continue to occur in Canada. The numbers of FNI children with disseminated disease was greater than expected from reported rates in the literature.

Predictors of death in infants hospitalized with pertussis: a case-control study of 16 pertussis deaths in Canada

ObjectivesTo describe the clinical course of fatal cases of pertussis and identify predictors of death at the time of presentation for medical care. MethodsCase-control study of 16 deaths from pertussis identified by the Immunization Monitoring Program, Active (IMPACT) surveillance network (January 1991-December 2001) matched with 32 nonfatal cases by age, date, and geography. Differences were compared by Fisher exact test and logistic regression. A multivariate model was developed using stepwise logistic regression. ResultsAll 16 fatal cases were ≤6 months old; 13 were <2 months old. Fatal cases were less likely to have had cough complications during pregnancy (48% vs 14%; P=.046) and more likely to have pneumonia (63% vs 16%; P=.0024) before hospital admission and more likely to have seizures, pneumonia, leukocytosis, and hypoxemia after admission (P<.001 for all comparisons). White blood cell count and pneumonia were independent predictors of fatal outcome in the multivariate model. ConclusionsInfants too young to have begun their immunizations are at highest risk of fatal pertussis infection. Leukocytosis and pneumonia are predictors of a poor outcome; however, rapid progression of the disease may make interventions difficult.

Assessing immunization programs

Assessing immunization programs

Assuring vaccine safety: A celebration of 10 years of progress with the IMPACT project

The Immunization Monitoring Program, ACTive (IMPACT) is a unique collaboration between Health Canada, the Canadian Paediatric Society (CPS) and paediatric infectious disease specialists to provide selected surveillance data on vaccine-preventable diseases and (possible) adverse reactions to immunization. The nationwide project recently celebrated its 10th year of active surveillance, during which time the capabilities of such a system have been extensively explored. The present brief report summarizes the history of the project and highlights its contributions to date.

Outcome of penicillin-nonsusceptible Streptococcus pneumoniae meningitis: a nested case-control study.

There are few data comparing the clinical features, management and outcome of penicillin-nonsusceptible (PNSP) meningitis patients with penicillin-susceptible (PSSP) meningitis patients. We performed a retrospective, nested case-control study comparing cases with PNSP meningitis with controls with PSSP meningitis obtained from the Immunization Monitoring Program, Active (IMPACT) cross-Canada surveillance study of invasive infections. There were 30 PNSP meningitis cases (10.1% of total) and 45 PSSP meningitis controls from 6 centers obtained from 297 meningitis cases in the IMPACT database from 1991 through 1999. Vancomycin was used for empiric therapy in no cases and controls in 1991 to 1993 and in all cases in 1999. A third generation cephalosporin was used in 93.3% of confirmed PNSP cases, and 70.0% also received vancomycin and/or rifampin. Penicillin was used in 66.7% of confirmed PSSP cases. PNSP cases were more likely than PSSP controls to have a second lumbar puncture (odds ratio, 4.1; P= 0.01). PNSP cases were treated with intravenous antibiotics for an average of 15.6 days compared with 12.3 days for controls ( P= 0.04). Among PNSP cases, those patients who did not receive empiric vancomycin were treated with intravenous antibiotics for an average of 18.5 days compared with 12.0 days for those who did receive empiric vancomycin ( P= 0.04). The overall mortality was 5.3%, and 36.6% of survivors had >or=1 neurologic sequelae, including 19.7% with hearing loss. In multivariate statistical models, PNSP was not a risk factor for intensive care unit admission or neurologic sequelae. Management of suspected bacterial meningitis and confirmed meningitis in Canadian children changed in the past decade. Treatment of PNSP meningitis is significantly different from that for PSSP meningitis. These changes have occurred in response to the emergence of PNSP in Canada. Neurologic sequelae remain common after meningitis, but there are no differences between PNSP cases and PSSP cases.