Scott A Halperin

IWK Health Centre, Halifax, Nova Scotia, Canada

Are you Scott A Halperin?

Claim your profile

Publications (317)1237.12 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The tetanus, diphtheria and acellular pertussis vaccine (Tdap) is recommended for all adults in both Canada and the United States. There are few data on the proportion of Canadian adults vaccinated with Tdap; however, anecdotal reports indicate that uptake is low. This study aimed to explore the knowledge, attitudes, beliefs, and behaviors of Canadian health care providers (HCPs) in an attempt to identify potential barriers and facilitators to Tdap uptake. HCPs were surveyed and a geographic and practice representative sample was obtained (n=1167). In addition 8 focus groups and 4 interviews were conducted nationwide. Results from the survey indicate that less than half (47.5%) of all respondents reported being immunized with Tdap themselves, while 58.5% routinely offer Tdap to their adult patients. Knowledge scores were relatively low (63.2% correct answers). The best predictor of following the adult Tdap immunization guidelines was an awareness of, and agreement with those recommendations. Respondents who were aware of the recommendations were more likely to think that Tdap is safe and effective, that their patients were at significant risk of getting pertussis, and to feel that they had sufficient information (p<0.0001 for each statement). Focus group data supported the survey results and indicated that there are substantial gaps in knowledge of pertussis and Tdap amongst Canadian HCPs. Lack of public knowledge around adult immunization, lack of immunization registries, costing differential between Td and Tdap, workload required to deliver the vaccine, and vaccine hesitancy were identified as barriers to compliance with the national recommendations for universal adult immunization and suggestions provided to better translate recommendations to front line practitioners.
    Human Vaccines & Immunotherapeutics 06/2015; DOI:10.1080/21645515.2015.1046662 · 3.64 Impact Factor
  • Lauren Davey, Scott A Halperin, Song F Lee
    [Show abstract] [Hide abstract]
    ABSTRACT: Streptococci secrete small peptides with important biological functions. These peptides are not amenable to standard immunoblotting, and are often detected indirectly using activity assays, or by alternative approaches that may be expensive and laborious. Here we describe an immunoblotting method that enables reproducible detection of these small streptococcal peptides. Copyright © 2015. Published by Elsevier B.V.
    Journal of microbiological methods 04/2015; 114. DOI:10.1016/j.mimet.2015.04.015 · 2.10 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Rotavirus is the most common cause of diarrhea leading to hospitalization in young children. Rotavirus vaccines are available in Canada but have not been introduced in all provinces. In a controlled trial, two study sites (Prince Edward Island and the Capital District Health Authority (District 9, Nova Scotia) introduced universal rotavirus vaccine programs for infants at two and four months of age beginning 1 December 2010, using public health nurse or general practitioner-delivery models, respectively. A third site (Saint John, NB) served as the non-intervention control setting. Vaccine coverage, rotavirus hospitalizations, intussusception and all-cause diarrhea were monitored. A universal rotavirus vaccine program with >90% coverage was associated with reductions in rotavirus-associated hospitalizations (from a peak of 52.8 hospitalizations/100,000 population to 0 hospitalizations) in infants < 12 months and 1 to < 2 years of age 12 months after program implementation. No apparent reduction occurred in the site with vaccine coverage of < 40%, or in the non-intervention control site. No cases of intussusception were associated with vaccine receipt, and no increase in all-cause diarrhea was observed. A universal infant rotavirus vaccine program with high coverage was associated with reductions in rotavirus and no safety signals; no reduction was observed in settings with low vaccine coverage.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Increasing the transparency of the evidence base behind health interventions such as pharmaceuticals, biologics, and medical devices, has become a major point of critique, conflict, and policy focus in recent years. Yet the lack of publicly available information regarding the immunogenicity assays upon which many important, widely used vaccines are based has received no attention to date. In this paper we draw attention to this critical public health problem by reporting on our efforts to secure vaccine assay information in respect of 10 vaccines through Canada's access to information law. We argue, under Canadian law, that the public health interest in having access to the methods for these laboratory procedures should override claims by vaccine manufacturers and regulators that this information is proprietary; and, we call upon several actors to take steps to ensure greater transparency with respect to vaccine assays, including regulators, private firms, researchers, research institutions, research funders, and journal editors.
    Human Vaccines & Immunotherapeutics 02/2015; 11(2):498-503. DOI:10.4161/21645515.2014.980194 · 3.64 Impact Factor
  • [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    ABSTRACT: This survey study compared pre- and post-pandemic knowledge, attitudes, beliefs, and intended behaviors of pregnant women regarding influenza vaccination (seasonal and/or pandemic) during pregnancy in order to determine key factors influencing their decision to adhere to influenza vaccine recommendations. Only 36% of 662 pre-pandemic respondents knew that influenza was more severe in pregnant women, compared to 62% of the 159 post-pandemic respondents. Of the pre-pandemic respondents, 41% agreed or strongly agreed that that it was safer to wait until after the first 3 months to receive the seasonal influenza vaccine, whereas 23% of the post-pandemic cohort agreed or strongly agreed; 32% of pre-pandemic participants compared to 11% of post-pandemic respondents felt it was best to avoid all vaccines while pregnant. Despite 61% of the pre-pandemic cohort stating that they would have the vaccine while pregnant if their doctor recommended it and 54% citing their doctor/nurse as their primary source of vaccine information, only 20% said their doctor discussed influenza vaccination during their pregnancy, compared to 77% of the post-pandemic respondents who reported having this conversation. Women whose doctors discussed influenza vaccine during pregnancy had higher overall knowledge scores (P < 0.0001; P = 0.005) and were more likely to believe the vaccine is safe in all stages of pregnancy (P < 0.0001; P = 0.001) than those whose doctors did not discuss influenza vaccination. The 2009 H1N1 pandemic experience appeared to change attitudes and behaviours of health care providers and their pregnant patients toward influenza vaccination.
    Human Vaccines and Immunotherapeutics 12/2014; 10(12):3629-3641. DOI:10.4161/21645515.2014.980684 · 3.64 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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; 33(4). DOI:10.1016/j.vaccine.2014.11.018 · 3.49 Impact Factor
  • Medicine 2.0 Scientific Meeting, Maui, Hawaii; 11/2014
  • [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    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; 32(48). DOI:10.1016/j.vaccine.2014.09.028 · 3.49 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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. DOI:10.1186/1471-2458-14-908 · 2.32 Impact Factor
  • [Show abstract] [Hide abstract]
    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 07/2014; 59(9). DOI:10.1093/cid/ciu597 · 9.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Regulatory B (Breg) cells are known to modulate immune responses through predominantly interleukin-10 (IL-10)-dependent mechanisms and can be hypothetically divided into innate and adaptive subsets based on the nature of their activating signals. However, the specific role of different Breg subsets in modulating immune responses remains ambiguous. Here we have shown that Chlamydia induces IL-10-producing splenic B-cell populations consisting of CD43(+) and CD43(-) subsets of IgM(hi)IgD(lo) innate-like B (ILB) cells in vitro. While CD43(+)IL-10-producing B cells displayed innate type features and were readily induced by Chlamydia via Toll-like-receptor (TLR) signaling, CD43(-)IL-10-producing B cells required additional B-cell activating factor (BAFF)-mediated signals from dendritic cells (DCs) for their differentiation and activation, thereby classifying them as adaptive type Bregs. Importantly, CD43(-), but not CD43(+), IL-10-producing ILB cells displayed bona fide Breg activity by potently suppressing interferon-γ (IFN-γ) production in vitro in an IL-10-dependent manner. Furthermore, a novel CD43(-)CD1d(hi)CD5(+) IL-10-producing Breg population was predominantly induced by Chlamydia genital infection in vivo. Correspondingly, mixed bone marrow chimeric mice with B-cell-specific IL-10 deficiency exhibited significantly increased type 1 immune responses, decreased bacterial burden, and reduced oviduct pathology upon infection. Our data demonstrate for the first time a distinct role for CD43(-)CD1d(hi)CD5(+)-adaptive Bregs over CD43(+) innate counterparts in controlling mucosal responses against intracellular bacterial infection.Mucosal Immunology advance online publication, 18 June 2014; doi:10.1038/mi.2014.45.
    Mucosal Immunology 06/2014; 8(1). DOI:10.1038/mi.2014.45 · 7.54 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
  • [Show abstract] [Hide abstract]
    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; 34(6). DOI:10.1007/s10875-014-0054-z · 2.65 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background 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. Methods A self-administered survey measuring knowledge, attitudes, beliefs and behaviours about pneumococcal vaccination was administered to a cohort of seniors participating in a clinical trial of seasonal influenza vaccines at eight centers across Canada. Eligible participants were ambulatory adults 65 years of age or older, in good health or with stable health conditions, previously given influenza vaccine. The primary outcome was self-reported receipt of pneumococcal vaccination. Multi-variable logistic regression was used to determine factors significantly associated with pneumococcal vaccine receipt. Results A total of 863 participants completed questionnaires (response rate 92%); 58% indicated they had received the pneumococcal vaccine. Being offered the vaccine by a health care provider had the strongest relationship with vaccine receipt (AOR 23.4 (95% CI 13.4-40.7)). Other variables that remained significantly associated with vaccine receipt in the multivariable model included having heard of the vaccine (AOR 10.1(95% CI 4.7-21.7)), and strongly agreeing that it is important for adults > 65 to be vaccinated against pneumococcus (AOR 3.3 (95% CI 1.2-9.2)). Participants who were < 70 years of age were less likely to be vaccinated. Conclusions These results indicate healthcare recommendation significantly influenced vaccine uptake in this population of older adults. Measures to encourage healthcare providers to offer the vaccine may help increase coverage.
    BMC Public Health 05/2014; 14(1):442. DOI:10.1186/1471-2458-14-442 · 2.32 Impact Factor
  • Tod J Merkel, Scott A Halperin
    [Show abstract] [Hide abstract]
    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. DOI:10.1093/infdis/jit493 · 5.78 Impact Factor
  • Eurosurveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 03/2014; 19(9). DOI:10.2807/1560-7917.ES2014.19.9.20729 · 4.66 Impact Factor

Publication Stats

6k Citations
1,237.12 Total Impact Points


  • 1997–2015
    • IWK Health Centre
      Halifax, Nova Scotia, Canada
  • 1989–2015
    • Dalhousie University
      • • Canadian Center for Vaccinology
      • • Department of Pediatrics
      Halifax, Nova Scotia, Canada
  • 2009–2013
    • BC Children's Hospital
      Vancouver, British Columbia, Canada
    • University of Toronto
      Toronto, Ontario, Canada
  • 2011
    • Crucell
      Leyden, South Holland, Netherlands
  • 2008
    • University of Oxford
      • Department of Paediatrics
      Oxford, ENG, United Kingdom
  • 2003–2008
    • University of Ottawa
      • • Division of Infectious Diseases
      • • Department of Pediatrics
      Ottawa, Ontario, Canada
    • St. Paul's Hospital
      Saskatoon, Saskatchewan, Canada
    • SickKids
      Toronto, Ontario, Canada
  • 2000
    • Children's Hospital of Eastern Ontario
      Ottawa, Ontario, Canada
    • University of Lethbridge
      Lethbridge, Alberta, Canada
    • University of British Columbia - Vancouver
      Vancouver, British Columbia, Canada
    • University of Manitoba
      Winnipeg, Manitoba, Canada
  • 1999
    • BC Centre for Disease Control
      Vancouver, British Columbia, Canada
  • 1996
    • Health Canada
      Ottawa, Ontario, Canada
  • 1992
    • Nova Scotia Museum
      Halifax, Nova Scotia, Canada