Scott A Halperin

IWK Health Centre, Halifax, Nova Scotia, Canada

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Publications (303)1147.46 Total impact

  • Manish Sadarangani, David W Scheifele, Scott A Halperin, Wendy Vaudry, Nicole Le Saux, Raymond Tsang, Julie A Bettinger
    Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 01/2015;
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    ABSTRACT: Objectives: Examine pertussis cycles between 1990 and 2013 and determinants by age group, immunization cohort and province/territory. Methods: National pertussis case reports were used. 2013 data are preliminary. Peak years were those in which incidence rates were above the preceding and proceeding years. Immunization cohorts were defined by year of birth and dates of program implementation by province/territory. Results: Introduction of acellular vaccine and adolescent booster programs occurred in all provinces/territories between 1997 and 2004. From 1990-1998, pertussis peaks occurred every 4 years with a mean increase of 82% from the preceding year and occurred uniformly across all age groups. The largest case contribution shifted from the 1-4 age group (1990-93) to the 5-9 age group (1994-98). From 1999-2007, no national peaks occurred, peaks within age groups were asynchronous, and the largest case contribution shifted from the 5-9 age group (1999), to the 10-14 age group (2000-05), to the 1-4 age group (2006-07). From 2008-2013, peaks occurred every 4 years and across all age groups with a 30% incidence increase in 2008 and 546% increase in 2012. The largest case contribution alternated between the 1-4 and 20+ age groups. Age groups in the adsorbed whole cell cohort contributed the most cases annually until 2006. National peak years were not dependent on the number of peaking provinces/territories but were typically in years with over 80% case contribution from peaking provinces/territories. Conclusions: Canadian pertussis cycles appear to have been altered by acellular vaccine and adolescent booster programs. Booster programs may have interrupted a marching cohort of children primed with adsorbed whole cell vaccine. With 4 year cycles resuming in 2008 and the 2012 peak, a new pattern of pertussis cycles may have begun. Given differences in cyclic patterns and immunization programs by province/territory, data should be examined by region.
    Canadian Immunization Conference, Ottawa, Ontario, Canada; 12/2014
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    ABSTRACT: Highly pathogenic avian influenza A/H5N1 viruses continue to circulate in birds and infect humans causing serious illness and death.Methods In this randomized, observer-blinded study, adults ≥18 years of age (n = 841) received 3.75 or 7.5 μg hemagglutinin antigen (HA) of an AS03-adjuvanted (AS03A or AS03B) A/Indonesia/5/2005 H5N1 (subclade 2.1) vaccine (priming), followed by the same HA dose of AS03-adjuvanted A/turkey/Turkey/1/05 H5N1 (clade 2.2) influenza vaccine as a booster 6 or 18 months after priming; an unprimed group received placebo at Day 0, and 3.75 μg HA of AS03A-adjuvanted booster vaccine at 6 and 18 months. Antibody responses were assessed by hemagglutination-inhibition assay (HI). Microneutralization (MN) antibody and cellular immunoassays were assessed in a subset of participants.ResultsGeometric mean titers (GMTs) and seroconversion rates (SCRs) were higher in primed vs. unprimed subjects against the booster strain 10 days following booster vaccination at month 6 and month 18. After the booster at 18 months, the lower limit of the 97.5% confidence interval for the difference in SCR and GMT ratios between primed and unprimed subjects was >15% and >2.0, respectively, fulfilling the primary endpoint criteria for superiority against the booster strain. MN and cellular immune responses corresponded with the immunogenicity seen in HI measures.Conclusions Adults primed with a dose-sparing oil-in-water adjuvanted H5N1 subclade vaccine had rapid and durable antibody responses to a heterologous subclade boosting vaccine given 6 or 18 months later.
    Vaccine 11/2014; · 3.49 Impact Factor
  • Medicine 2.0 Scientific Meeting, Maui, Hawaii; 11/2014
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    ABSTRACT: Background: Group B Streptococcus (GBS) is a serious cause of meningitis and sepsis in young infants. We assessed maternal immunization with an investigational trivalent GBS polysaccharide-CRM conjugate vaccine, with follow-up of both mothers and infants ( NCT01446289). Methods: In a phase II, observer-blind, placebo-controlled study, 86 pregnant women were enrolled at 24–35 weeks gestation and randomized 3:2 to receive intramuscular placebo (saline) or trivalent GBS vaccine containing 5 µg of glycoconjugates of each of GBS serotypes Ia, Ib and III. GBS serotype-specific antibodies were measured in mothers pre- and Day 31 post-immunization, and in mothers and infants at delivery and Day 91 post-partum. Safety was assessed up to at least 5 months postpartum. Results: Of 86 pregnant women enrolled (age 29.8 ± 5.1 years, mean ± SD), 51 received vaccine and 35 placebo at 30.0 ± 3.3 weeks gestation. Low pre-immunization antibodies against serotypes Ia, Ib and III increased 16-, 23- and 20-fold, respectively, at delivery. Among maternal-infant pairs with detectable antibodies, placental transfer was 81% (n=38), 70% (n=35) and 65% (n=33), against serotypes Ia, Ib and III. Infants of vaccinated mothers had increased antibody levels at birth which persisted above placebo group levels through day 91 of age. ELISA GMCs (µg/mL) [95% CI] GBS Serotype Ia Ib III Study Group GBS Placebo GBS Placebo GBS Placebo Mothers N 51 35 51 35 51 35 GMC - Delivery [95% CI] 5.22 [3.37, 8.1] 0.37 [0.22, 0.63] 2.41 [1.48, 3.94] 0.13 [0.07, 0.23] 1.90 [1.15, 3.12] 0.11 [0.06, 0.19] Infants N 35 25 31 20 30 22 GMC - Birth [95% CI] 5.14 [2.64, 10] 0.33 [0.15, 0.71] 2.93 [1.14, 7.57] 0.1 [0.03, 0.32] 1.93 [0.82, 4.59] 0.07 [0.02, 0.18] Infants N 35 25 35 25 35 25 GMC - 91 days [95% CI] 1.28 [0.76, 2.16] 0.25 [0.13, 0.46] 0.54 [0.25, 1.19] 0.06 [0.03, 0.16] 0.43 [0.21, 0.86] 0.07 [0.03, 0.15] Mild or moderate solicited reactions were reported in 54% and 53% of vaccine and placebo groups, respectively, with no vaccine-related SAEs reported. Conclusion: One dose of trivalent GBS vaccine was well-tolerated with no concerning safety signals in pregnant women, and induced increased antibody concentrations in mothers and their infants.
    IDWeek 2014 Meeting of the Infectious Diseases Society of America; 10/2014
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    ABSTRACT: Infants under 6 months of age are at greatest risk of mortality and severe morbidity from pertussis disease. Interventions that increase pertussis protection in newborns are therefore a clear public health imperative. The objective of this study was to assess maternal pertussis toxin antibody (anti-PT) level as a potential source of mother-to-child transfer of pertussis-associated antibodies that may reduce neonatal risk of pertussis disease. Anti-PT level was assessed in a 2013 cohort of pregnant women from two regions in two Canadian provinces, British Columbia and Nova Scotia. Basic demographics, health, and pertussis immunization history were collected, along with blood specimens. Anti-PT levels were compared for self-reported vaccination status and prior pertussis disease. To assess secular trend, a parallel analysis was also undertaken, using anonymized residual sera from a 1996-1997 cohort of pregnant women in British Columbia. A total of 169 pregnant women participated in the prospective study - 50 from Nova Scotia and 119 from British Columbia. The mean and median age of participants from both sites was 31 years of age (range 16-42 years). The lower limit of quantification of the anti-PT assay was 10 ELISA units per milliliter (EU/ml). Overall, 59% of women had anti-PT levels less than 10EU/ml and anti-PT level did not differ with time since last self-reported pertussis vaccination (χ(2)(2)=3.166, p=0.205). Among a 1996-1997 cohort of pregnant women in British Columbia, 51% had anti-PT levels less than 10EU/ml. Our study found that most pregnant women in two geographically disparate health regions in Canada have low residual anti-PT levels, may be vulnerable to pertussis infection themselves, and would unlikely be a source of passive ante- or postnatal transfer of anti-PT to their newborn.
    Vaccine 09/2014; · 3.49 Impact Factor
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    ABSTRACT: Rotavirus vaccine is recommended for all infants in Canada. To evaluate the logistics of implementing a universal rotavirus vaccination program, we compared the effectiveness of program implementation in jurisdictions with either a physician-administered or public health nurse-administered program.
    BMC Public Health 09/2014; 14(1):908. · 2.32 Impact Factor
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    ABSTRACT: Background. Before 2001, the incidence of invasive meningococcal disease (IMD) in Canada was 1.0 per 100,000 per year, with 40% of cases caused by serogroup C organisms. During 2001-2005 all provinces introduced the meningococcal serogroup C conjugate vaccine (MCCV) into their routine infant immunization schedule. Methods. Active, prospective, population-based surveillance of IMD in children and adults was conducted by the Canadian Immunization Monitoring Program, ACTive (IMPACT) during 2002-2012. Inclusion criteria were admission to hospital and identification of Neisseria meningitidis from a sterile site. Incidence was estimated using population census data from Statistics Canada. Results. Prior to MCCV introduction, serogroup C disease incidence was 0.07-0.25 per 100,000 per year depending on the province. Following vaccine introduction, serogroup C disease decreased to <0.05 per 100,000 per year, with a reduction of 14% per year (p=0.0014). A decrease occurred in all provinces, despite differing schedules being implemented. The largest decrease of 83% (from 0.27 to 0.05 per 100,000 per year) occurred in the 15-24 year age group (p=0.0100) who were not vaccinated in all provinces. There was no impact on the incidence of non-serogroup C disease over the same period (p=0.9811). Conclusions. MCCV dramatically reduced the incidence of serogroup C IMD in Canada through both direct and indirect effects. The observation that disease incidence decreased with different schedules suggests that the doses at 12 months (common to all provinces) and adolescence (7 of 8 provinces studied) were critical in achieving disease control.
    Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 07/2014;
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    ABSTRACT: When moderate or severe adverse events occur after vaccination, physicians and patients may have concerns about future immunizations. Similar concerns arise in patients with underlying conditions whose risk for adverse events may differ from the general population. The Special Immunization Clinic (SIC) network was established in 2013 at 13 sites in Canada to provide expertise in the clinical evaluation and vaccination of these patients.
    Paediatrics & child health. 06/2014; 19(6):310-4.
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    ABSTRACT: More severe influenza disease and poor vaccine immunogenicity is reported in HIV-infected patients. We measured antibody avidity after influenza vaccination in HIV patients to assess vaccine efficacy. Two dosing strategies (Group1: single dose, n = 28. Group2: single dose plus booster, n = 36) with an AS03A-adjuvanted H1N12009 pandemic influenza vaccine (Arepanrix, GSK) were assessed in HIV patients. Serum hemagglutination inhibition (HAI) titers and antibody avidity reported as an avidity index (AI) were measured at days 21 and 42 and at 6 months. Baseline HIV parameters were similar among all participants. Eighteen participants had measurable baseline HAI titers. In these subjects, AI was at ~9 at baseline and was not significantly increased by one or two vaccine doses. In those without detectable baseline antibodies, immunization induced modest antibody titers [Group1 HAI, 61 (26-144); Group2 HAI, 46 (28-76)] with high AI after one dose at day 21 [Group1 AI, 8.8 (7.3-10.7); Group2 AI, 8.9 (7.8-10.1)]. A second dose of vaccine generated significantly higher HAI titers at day 42 [Group1 HAI, 41 (18-90); Group2 HAI, 92 (64-132)] and persisted to 6 months [Group1 HAI, 9 (6-13); Group2 HAI, 19 (13-30)]. All subjects who produced detectable HAI titers after vaccination generated high antibody avidity (AI, 9-10), which persisted up to 6 months. In participants initially seronegative, two doses of vaccine enabled a greater percentage of subjects to respond to the vaccine and elicited higher HAI titers. All subjects who produced detectable HAI titers also rapidly generated high AI in the short and long term. We demonstrate that high avidity antibodies can be achieved after vaccination and support a two-dose immunization strategy for HIV-positive subjects.
    Journal of Clinical Immunology 05/2014; · 2.65 Impact Factor
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    ABSTRACT: Fewer Canadian seniors are vaccinated against pneumococcal disease than receive the influenza vaccine annually. Improved understanding of factors influencing pneumococcal vaccination among older adults is needed to improve vaccine uptake.
    BMC Public Health 05/2014; 14(1):442. · 2.32 Impact Factor
  • Paediatrics & child health. 05/2014; 19(5):237-8.
  • Tod J Merkel, Scott A Halperin
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    ABSTRACT: Despite pertussis vaccination rates in excess of 95%, pertussis rates in the United States have been rising over the last 30 years, with increasingly larger outbreaks in 2004, 2010, and 2012. The reasons for this resurgence of pertussis are not clearly understood. The recent development of a baboon model of pertussis, along with the future development of a human challenge model of pertussis, has the potential to provide a path forward for answering critical questions about pertussis pathogenesis and host responses and will likely aid in the development of next-generation pertussis vaccines.
    The Journal of Infectious Diseases 04/2014; 209 Suppl 1:S20-3. · 5.85 Impact Factor
  • Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 03/2014; 19(9). · 4.66 Impact Factor
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    ABSTRACT: Universal immunization of adolescents against meningococcal disease with a quadrivalent meningococcal ACWY (MenACWY) conjugate vaccine is recommended in a number of countries. In a randomized, controlled, observer-blinded, multicenter trial, 1016 participants, 10-25 years of age, were randomly allocated 1:1:1 to receive a single dose of 1 of 2 lots of an investigational tetanus toxoid-conjugated MenACWY vaccine (MenACWY-TT) or a marketed diphtheria toxoid-conjugated MenACWY vaccine (MenACWY-DT). The primary outcome was the noninferiority of the vaccine response after MenACWY-TT (lot A) compared with MenACWY-DT for all 4 serogroups. Vaccine response was defined as a postvaccination human serum bactericidal antibody (hSBA) titer against each of the serogroups of at least 1:8 in persons initially seronegative (<1:4) or as a 4-fold increase in titer pre- to postvaccination in persons initially seropositive (≥1:4). Adverse events (AEs) after immunization were measured 4 and 31 days postvaccination. The mean age of participants was 16.3 years; 977 (96.6%) completed the study. The noninferiority of MenACWY-TT (lot A) to the control vaccine in terms of the percentage of participants with hSBA vaccine response was demonstrated for each serogroup. Vaccine response rates ranged from 51.0% to 82.5% for the 4 serogroups after MenACWY-TT (both lots) compared with 39.0%-76.3% for the 4 serogroups after MenACWY-DT. Pain was the most common injection-site reaction reported by 50.8%-55.4% across the 3 groups. Fatigue and headache were the most common systemic solicited AEs, reported by 27.3%-29.2% and 25.5%-26.4%, respectively. Tetanus toxoid-conjugated MenACWY vaccine was well tolerated and elicited an immune response that was noninferior to that of a marketed MenACWY-DT ( NCT01165242).
    Journal of the Pediatric Infectious Diseases Society. 03/2014; 3(1):33-42.
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    ABSTRACT: Combination diphtheria-tetanus-5 component acellular pertussis-inactivated poliovirus-Haemophilus influenzae b conjugate-hepatitis B vaccine (DTaP5-IPV-Hib-HepB) administered either concurrently with 7-valent pneumococcal conjugate vaccine (PCV7) or 1 month apart was generally safe and immunogenic at 2, 4 and 6 months of age. This study examined the effects of a booster dose at age 15 months. Participants were randomized to DTaP5-IPV-Hib-HepB plus PCV7, DTaP5-IPV-Hib-HepB with PCV7 administered 1 month later or a pentavalent DTaP5-IPV/Hib plus HepB plus PCV7 at 15 months of age in a randomized, open-label, phase IIb clinical trial. Immunogenicity endpoints were rates of seroresponse to pertussis toxoid, filamentous hemagglutinin, pertactin and fimbriae types 2 and 3; rates of seroprotection against (Hib) polyribosylribitol phosphate capsular polysaccharide, hepatitis B surface antigen, diphtheria toxoid, tetanus toxoid and poliovirus types 1, 2 and 3; and geometric mean titers to all vaccine antigens. Safety endpoints included solicited injection-site reactions and systemic and serious adverse events. Seroresponse/seroprotection rates for all antigens exceeded prespecified criteria in both groups that received the hexavalent DTaP5-IPV-Hib-HepB; in the group that received the currently licensed pentavalent vaccine, seroresponse/seroprotection rates exceeded the criteria for all antigens except filamentous hemagglutinin. Seroresponse rates were ≥88.9% for pertussis antigens and seroprotection rates against polyribosylribitol phosphate capsular polysaccharide, hepatitis B surface antigen, diphtheria toxoid, tetanus toxoid and poliovirus antigens were ≥95.1% in recipients of DTaP5-IPV-Hib-HepB. DTaP5-IPV-Hib-HepB administered concomitantly with PCV7 or 1 month apart at 15 months of age following the infant series was well-tolerated and elicited antibody responses to all vaccine antigens, with no significant interference from concomitant PCV7 administration ( registration number NCT00362427).
    The Pediatric Infectious Disease Journal 01/2014; 33(1):73-80. · 3.14 Impact Factor
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    ABSTRACT: Funded immunization programs are best able to achieve high participation rates, optimal protection of the target population, and indirect protection of others. However, in many countries public funding of approved vaccines can be substantially delayed, limited to a portion of the at-risk population or denied altogether. In these situations, unfunded vaccines are often inaccessible to individuals at risk, allowing potentially avoidable morbidity and mortality to continue to occur. We contend that private access to approved but unfunded vaccines should be reconsidered and encouraged, with recognition that individuals have a prerogative to take advantage of a vaccine of potential benefit to them whether it is publicly funded or not. Moreover, numbers of "approved but unfunded" vaccines are likely to grow because governments will not be able to fund all future vaccines of potential benefit to some citizens. New strategies are needed to better use unfunded vaccines even though the net benefits will fall short of those of funded programs. Canada, after recent delays funding several new vaccine programs, has developed means to encourage private vaccine use. Physicians are required to inform relevant patients about risks and benefits of all recommended vaccines, publicly funded or not. Likewise, some provincial public health departments now recommend and promote both funded and unfunded vaccines. Pharmacists are key players in making unfunded vaccines locally available. Professional organizations are contributing to public and provider education about unfunded vaccines (e.g. herpes zoster, not funded in any province). Vaccine companies are gaining expertise with direct-to-consumer advertising. However, major challenges remain, such as making unfunded vaccines more available to low-income families and overcoming public expectations that all vaccines will be provided cost-free, when many other recommended personal preventive measures are user-pay. The greatest need is to change the widespread perception that approved vaccines should be publicly funded or ignored.
    Vaccine 12/2013; · 3.49 Impact Factor
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    ABSTRACT: The Canadian Adverse Event Following Immunization Surveillance System (CAEFISS) receives report 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. To 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). Reports 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. There 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. Incorporating 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.
    Vaccine 10/2013; · 3.49 Impact Factor
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    ABSTRACT: The functional role of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) in host responses to intracellular bacterial infection was investigated in an in vitro coculturing system and a murine model of Chlamydia muridarum genital tract infection. Remarkably, C. muridarum infection subverted the immune suppressive role of CD4(+)CD25(+)Foxp3(+) Tregs; instead of hampering immune responses, Tregs not only promoted Th17 differentiation from conventional CD4(+) T cells but also themselves converted into proinflammatory Th17 cells in both in vitro and in vivo settings. Anti-CD25 mAb PC61 treatment to deplete ∼50% of pre-existing Tregs prior to C. muridarum genital tract infection markedly reduced the frequency and the total number of Th17 but not Th1 CD4(+) cells at both immune induction and memory phases. Most importantly, Treg-depleted mice displayed significantly attenuated inflammation, neutrophil infiltration, and reduced severity of oviduct pathology upon C. muridarum genital infection. To our knowledge, this is the first report demonstrating that the level of pre-existing CD4(+)CD25(+)Foxp3(+) Tregs in Chlamydia-infected hosts has a major impact on the development Chlamydia-associated diseases.
    The Journal of Immunology 08/2013; · 5.36 Impact Factor
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    ABSTRACT: Background. Mismatch between circulating influenza B viruses (Yamagata and Victoria lineages) and vaccine strains occurs frequently.Methods. In a randomized controlled trial, immunogenicity and safety of an inactivated quadrivalent influenza vaccine candidate (QIV) versus trivalent inactivated influenza vaccine (TIV)-Victoria(Vic) and TIV-Yamagata(Yam) in children 3-17 years of age was evaluated. In an open-label study arm, QIV only was assessed in children 6-35 months of age.Results. A total of 3094 children (932 QIV, 929 TIV-Vic, 932 TIV-Yam, and 301 QIV only) were vaccinated. QIV was noninferior to the TIVs for shared strains (A/H3N2 and A/H1N1) based on hemagglutination-inhibition (HI) antibodies 28 days after last vaccination, and superior for the unique B strains Victoria and Yamagata (geometric mean titer ratios 2.61, 3.78; seroconversion rate differences 33.96%, 44.63%). Among children in the randomized trial, adverse event rates were similar except for injection site pain (dose 1: 65.4% QIV, 54.6% TIV-Vic, 55.7% TIV-Yam).Conclusion. QIV elicited superior HI responses to the added B strains compared to TIV controls, potentially improving its effectiveness against influenza B. HI responses were similar between QIV and TIV controls for the shared strains. QIV had an acceptable safety profile relative to TIVs.Clinical Trials Registration. NCT01198756.
    The Journal of Infectious Diseases 07/2013; · 5.85 Impact Factor

Publication Stats

5k Citations
1,147.46 Total Impact Points


  • 1997–2014
    • IWK Health Centre
      Halifax, Nova Scotia, Canada
  • 1988–2014
    • Dalhousie University
      • • Canadian Center for Vaccinology
      • • Department of Microbiology and Immunology
      • • Faculty of Dentistry
      • • Department of Pediatrics
      Halifax, Nova Scotia, Canada
  • 2011–2013
    • University of Saskatchewan
      • Vaccine and Infectious Disease Organization
      Saskatoon, Saskatchewan, Canada
    • Crucell
      Leyden, South Holland, Netherlands
  • 2009–2013
    • BC Children's Hospital
      Vancouver, British Columbia, Canada
  • 2008–2012
    • University of Oxford
      • Department of Paediatrics
      Oxford, ENG, United Kingdom
  • 2010–2011
    • Children's Hospital of Eastern Ontario
      Ottawa, Ontario, Canada
  • 2000–2011
    • University of Manitoba
      Winnipeg, Manitoba, Canada
  • 2009–2010
    • University of Toronto
      • Division of Infectious Diseases
      Toronto, Ontario, Canada
  • 2008–2009
    • Centers for Disease Control and Prevention
      • Division of HIV/AIDS Prevention, Intervention and Support
      Druid Hills, GA, United States
  • 2003–2009
    • University of Ottawa
      • • Division of Infectious Diseases
      • • Department of Pediatrics
      Ottawa, Ontario, Canada
    • Children's & Women's Health Centre of British Columbia
      Vancouver, British Columbia, Canada
    • St. Paul's Hospital
      Saskatoon, Saskatchewan, Canada
  • 2004–2006
    • McGill University Health Centre
      Montréal, Quebec, Canada
  • 2000–2003
    • University of British Columbia - Vancouver
      Vancouver, British Columbia, Canada
  • 1999
    • Institut National de Santé Publique du Québec (INSPQ)
      Québec, Quebec, Canada
    • BC Centre for Disease Control
      Vancouver, British Columbia, Canada
  • 1996
    • Health Canada
      Ottawa, Ontario, Canada
  • 1992
    • Nova Scotia Museum
      Halifax, Nova Scotia, Canada