A CCR2/5 Inhibitor, PF-04634817, Is Inferior to Monthly Ranibizumab in the Treatment of Diabetic Macular Edema.

Purpose: Ligands for the proinflammatory C-C chemokine receptor types 2 and 5 (CCR2 and CCR5) are elevated in the eyes of patients with diabetic macular edema (DME). We evaluated the efficacy and safety of PF-04634817, an oral CCR2/5 dual antagonist, versus intravitreal ranibizumab, in adult subjects with DME. Methods: In this phase II, randomized, placebo-controlled, double-masked study, eligible subjects (≥18 years of age) had type 1 or 2 diabetes and DME with best-corrected visual acuity (BCVA) of 20/32 or worse (letter score ≤ 78), and up to 20/320 or better (≥24 letter score), in the study eye. Subjects were assigned randomly 1:1 to once-daily (QD) oral PF-04634817 200 mg plus masked sham therapy as placebo or monthly intravitreal ranibizumab 0.3/0.5 mg plus QD oral placebo. The primary objective was to evaluate the efficacy of PF-04634817 compared with ranibizumab in change from baseline in BCVA after 12 weeks in a noninferiority design. Noninferiority was based on BCVA 80% confidence interval (CI): there had to be a less than three letter loss in the PF-04634817 arm compared with the ranibizumab arm. Results: A total of 199 subjects were randomized. Least squares mean difference in change in BCVA from baseline to week 12 in the study eye for the PF-04634817 arm was -2.41 letters (80% CI: -3.91, -0.91; P = 0.04) compared with ranibizumab. PF-04634817 was well tolerated. Conclusions: Treatment with oral CCR2/5 receptor dual antagonist PF-04634817 was associated with a modest improvement in BCVA, but did not meet the predefined noninferiority criteria compared with intravitreal ranibizumab.

Neutrophil killing of Staphylococcus aureus in diabetes, obesity and metabolic syndrome: a prospective cellular surveillance study.

BACKGROUND: Obesity, metabolic syndrome (MetS), and diabetes are frequent in surgical populations and can enhance susceptibility to postoperative surgical site infections. Reduced neutrophil function has been linked with diabetes and risk of Staphylococcus aureus infection. Therefore, neutrophil function in diabetic and obese subjects (± MetS) was assessed in this prospective serological and cellular surveillance study to determine whether vaccines administered to protect against infections after surgery could be effective in these populations. METHODS: Neutrophil function (chemotaxis, phagocytosis, and opsonophagocytic killing of S. aureus) was assessed in subjects classified according to diabetes status, body mass index, and presence/absence of MetS. Neutrophils were characterized within functional subsets by flow cytometry. A serologic assay was used to measure baseline antibody presence to each antigen in SA4Ag: capsular polysaccharide (CP) type 5, CP8, recombinant mutant Clumping factor A (rmClfA), and recombinant Manganese transport protein C (rMntC). RESULTS: Neutrophil function was similar for comorbid and healthy cohorts, with no significant between-group differences in cell counts, migration, phagocytosis ability, neutrophil subset proportions, and S. aureus killing ability when neutrophils were isolated 3-6 months apart (Visit 1 [n = 90] and Visit 2 [n = 70]) and assessed. Median pre-existing antibody titers to CP5, CP8, and rmClfA were comparable for all cohorts (insufficient subjects with rMntC titers for determination). CONCLUSIONS: MetS, diabetes, and obesity do not impact in vitro neutrophil function with regard to S. aureus killing, suggesting that if an effective S. aureus vaccine is developed it may be effective in individuals with these comorbidities.

Safety, tolerability, and immunogenicity of a 4-antigen Staphylococcus aureus vaccine (SA4Ag): Results from a first-in-human randomised, placebo-controlled phase 1/2 study.

BACKGROUND: A prophylactic Staphylococcus aureus four-antigen vaccine (SA4Ag) is under development for prevention of invasive S. aureus disease. A preliminary S. aureus three-antigen vaccine (SA3Ag) was reformulated to include a novel manganese transporter protein (MntC or rP305A). This study describes the first-in-human dose-finding, safety, and immunogenicity results for SA4Ag. METHODS: In this double-blind, sponsor-unblind, placebo-controlled, phase 1/2 study, 454 healthy adults aged 18-64years were randomised to receive a single dose of one of three formulations of SA4Ag with escalating dose levels of rP305A or placebo. Functional immune responses were measured using opsonophagocytic activity (OPA) killing and fibrinogen-binding inhibition (FBI) assays; antigen-specific immunogenicity was assessed using a four-plex competitive Luminex® immunoassay (cLIA). RESULTS: A high proportion of SA4Ag recipients met the pre-defined antibody thresholds for each antigen at Day 29. A substantial and dose-level dependent immune response was observed for rP305A, with up to 18-fold rises in cLIA titres at Day 29. Robust functional responses were demonstrated, with >80-fold and >20-fold rises in OPA assay titres at Day 29 using S. aureus strains expressing capsular polysaccharide serotypes 5 and 8, respectively. Durable antibody responses were observed through month 12, gradually waning from peak levels achieved by days 11-15. SA4Ag was well tolerated, and no vaccine-related serious adverse events were reported. CONCLUSIONS: Single-dose vaccination of SA4Ag in healthy adults aged 18-64years safely induced rapid and robust functional immune responses that were durable through month 12, supporting further development of this vaccine. TRIAL REGISTRATION NUMBER: NCT01364571.

Safety, tolerability, and immunogenicity of a single dose 4-antigen or 3-antigen Staphylococcus aureus vaccine in healthy older adults: Results of a randomised trial.

BACKGROUND: The decline in immune function with age is a challenge to vaccine development. Following an initial study in adults aged 18-64years, this study evaluated the safety and immunogenicity of Staphylococcus aureus (S. aureus) 4-antigen (SA4Ag) and 3-antigen (SA3Ag) vaccine in older adults. SA3Ag included capsular polysaccharide serotypes 5 and 8 (CP5 and CP8) conjugated to the nontoxic mutant form of diphtheria toxin (CRM197) and a recombinant version of clumping factor A (ClfA). SA4Ag included these antigens, with the addition of a recombinant manganese transporter C (rP305A or MntC). Both vaccines were unadjuvanted. METHODS: In this double-blind, sponsor-unblinded, placebo-controlled, phase 1/2 study, 284 healthy adults (aged 65-85years) were randomised to receive a single dose of one of three formulations of SA4Ag with escalating dose levels of rP305A, SA3Ag, or placebo. Functional immune responses were measured using opsonophagocytic activity (OPA) killing and fibrinogen-binding inhibition (FBI) assays; immunogenicity was also assessed using a competitive Luminex® immunoassay (cLIA). T-cell responses were measured in a small subgroup of subjects using intracellular cytokine staining (ICS) assays. RESULTS: The results demonstrated rapid and robust functional immune responses to all antigens in healthy older adults. A high proportion of active vaccine recipients met the pre-defined antibody thresholds for each antigen at Day 29. SA4Ag elicited a dose-level response to rP305A with up to a 13-fold rise in cLIA titres at Day 29. Opsonophagocytic activity (OPA) assays showed >50- and >20-fold rises in functional titres using S. aureus strains expressing CP5 and CP8, respectively, at Day 29. T-cell cytokine responses were not substantially above background levels. There were no safety concerns in this study population and no increases in adverse events with higher rP305A dose levels. CONCLUSIONS: Single-dose vaccination of SA4Ag and SA3Ag in healthy adults aged 65-85years safely induced rapid and robust functional immune responses, supporting further development of SA4Ag for the prevention of S. aureus disease in adults up to age 85years. TRIAL REGISTRATION NUMBER: NCT01643941.

Burden of Surgical Site Infections Associated with Select Spine Operations and Involvement of Staphylococcus aureus.

BACKGROUND: Spine operations may be indicated for treatment of diseases including vertebral injuries, degenerative spinal conditions, disk disease, spinal misalignments, or malformations. Surgical site infection (SSI) is a clinically important complication of spine surgery. Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA), is a leading cause of post-spinal SSIs. METHODS: PubMed and applicable infectious disease conference proceedings were searched to identify relevant published studies. Overall, 343 full-text publications were screened for epidemiologic, mortality, health care resource utilization, and cost data on SSIs associated with specified spine operations. RESULTS: Surgical site infection rates were identified in 161 studies from North America, Europe, and Asia. Pooled average SSI and S. aureus SSI rates for spine surgery were 1.9% (median, 3.3%; range, 0.1%-22.6%) and 1.0% (median, 2.0%; range, 0.02%-10.0%). Pooled average contribution of S. aureus infections to spinal SSIs was 49.3% (median, 50.0%; range, 16.7%-100%). Pooled average proportion of S. aureus SSIs attributable to MRSA was 37.9% (median, 42.5%; range, 0%-100%). Instrumented spinal fusion had the highest pooled average SSI rate (3.8%), followed by spinal decompression (1.8%) and spinal fusion (1.6%). The SSI-related mortality rate among spine surgical patients ranged from 1.1%-2.3% (three studies). All studies comparing SSI and control cohorts reported longer hospital stays for patients with SSIs. Pooled average SSI-associated re-admission rate occurring within 30 d from discharge ranged from 20% to 100% (four studies). Pooled average SSI-related re-operation rate was 67.1% (median, 100%; range, 33.5%-100%). According to two studies reporting direct costs, spine surgical patients incur approximately double the health care costs when they develop an SSI. CONCLUSIONS: Available published studies demonstrate a clinically important burden of SSIs related to spine operations and the substantial contribution of S. aureus (including MRSA). Preventive strategies aimed specifically at S. aureus SSIs could reduce health care costs and improve patient outcomes for spine operations.

Safety and immunogenicity of a booster dose of a 3-antigen Staphylococcus aureus vaccine (SA3Ag) in healthy adults: A randomized phase 1 study.

OBJECTIVE: A 2-stage, phase 1, randomized, placebo-controlled study in healthy adults to assess immunogenicity and safety of a booster dose at three dose levels of a 3-antigen Staphylococcus aureus vaccine (SA3Ag) containing recombinant clumping factor A (ClfA) and capsular polysaccharides 5 and 8 (CP5 and CP8) conjugated to a diphtheria toxoid. METHODS: Six months after initial single vaccination, in Stage 2, SA3Ag recipients were randomized (1:1) to booster vaccination or placebo, while Stage 1 placebo recipients received placebo again. Pre- and post-vaccination blood samples were analyzed. RESULTS: In Stage 2 (n = 345), pre-booster CP5 and CP8 titers remained high with no increase post-booster. ClfA titers remained high after initial vaccination and increased post-booster, approaching the peak response to the initial dose. Post-booster local reactions were more frequent and of greater severity than reported after the initial vaccination, particularly for the high-dose level recipients. Post hoc analysis showed no dose-response pattern and no obvious association between diphtheria toxoid titers and local reactions after initial or booster vaccination. CONCLUSION: Immune responses after the initial vaccination persisted for the 12 months studied, with little additional response after the booster dose at 6 months. Post-booster injection site reactions were more frequent and more severe but self-limiting. CLINICALTRIALS. GOV IDENTIFIER: NCT01018641.

Burden of Surgical Site Infections Associated with Arthroplasty and the Contribution of Staphylococcus aureus.

BACKGROUND: Patients undergoing arthroplasty are at considerable risk of experiencing post-operative complications, including surgical site infections (SSIs). In addition to potential economic consequences, SSIs can have a negative impact on patient outcomes and may potentially be life-threatening. Staphylococcus aureus has been consistently shown as the leading cause of SSIs associated with orthopedic surgery, with an important contribution from methicillin-resistant S. aureus (MRSA). This study evaluated the global burden of SSIs among patients undergoing orthopedic surgical procedures, and specifically those undergoing knee and hip arthroplasties. METHODS: An extensive search of PubMed and recent conference proceedings was conducted. English articles published between 2003 and 2013 pertaining to SSI epidemiology, patient outcomes, and healthcare resource utilization and costs were reviewed. RESULTS: Overall, 81 studies were included, mainly from North America and Europe. Median SSI and S. aureus SSI rates, calculated as percentage of all arthroplasty procedures, were 1.7% (range: 0.25%-4.4%; 15 studies) and 0.6% (range: 0.1%-23%), respectively. Median SSI rates were 1.3% (range: 0.05%-19%; 22 studies) after knee arthroplasty, and 2.1% (range: 0.05%-28%; 24 studies) after hip arthroplasty. S. aureus SSI rates ranged from 0.2%-2.4% and 0.18%-3.8% for patients undergoing knee and hip arthroplasty, respectively. The percentage of S. aureus SSIs because of MRSA varied widely within each patient category. SSI-related mortality data (14 studies) showed that in-hospital mortality rates were low (1.2%-2.5%), but increased with time after index arthroplasty procedure (up to 56% over 1 y). Studies assessing healthcare resource utilization (n = 21) revealed that developing post-orthopedic SSIs resulted in a two- to three-fold increase in length of hospital stay (LOS) compared with non-infected patients (median LOS: 18.9 d vs. 6 d for non-SSI patients). Patients with SSIs because of methicillin-resistant staphylococci incurred greater mean LOS compared with SSIs because of methicillin-sensitive organisms. Readmission rates reported in 11 studies indicate a greater likelihood in the presence of SSIs; comparison across studies was not feasible because of differences in data reporting. Consistent with increased healthcare resource utilization (LOS and readmission) associated with SSIs, cost studies (n = 23) revealed that the presence of SSIs was associated with up to three-fold cost increase compared with the absence of SSI across all orthopedic patient categories assessed. CONCLUSIONS: SSIs are associated with increased morbidity, mortality rates, healthcare resource utilization, and costs. Despite the relatively low SSI incidence following orthopedic surgery and specifically arthroplasty, preventive methods, specifically those targeting S. aureus, would serve to minimize costs and improve patient outcomes.

Evaluation of approaches to monitor Staphylococcus aureus virulence factor expression during human disease.

Staphylococcus aureus is a versatile pathogen of medical significance, using multiple virulence factors to cause disease. A prophylactic S. aureus 4-antigen (SA4Ag) vaccine comprising capsular polysaccharide (types 5 and 8) conjugates, clumping factor A (ClfA) and manganese transporter C (MntC) is under development. This study was designed to characterize S. aureus isolates recovered from infected patients and also to investigate approaches for examining expression of S. aureus vaccine candidates and the host response during human infection. Confirmation of antigen expression in different disease states is important to support the inclusion of these antigens in a prophylactic vaccine. Hospitalized patients with diagnosed S. aureus wound (27) or bloodstream (24) infections were enrolled. Invasive and nasal carriage S. aureus isolates were recovered and characterized for genotypic diversity. S. aureus antigen expression was evaluated directly by real-time, quantitative, reverse-transcriptase PCR (qRT-PCR) analysis and indirectly by serology using a competitive Luminex immunoassay. Study isolates were genotypically diverse and all had the genes encoding the antigens present in the SA4Ag vaccine. S. aureus nasal carriage was detected in 55% of patients, and in those subjects 64% of the carriage isolates matched the invasive strain. In swab samples with detectable S. aureus triosephosphate isomerase housekeeping gene expression, RNA transcripts encoding the S. aureus virulence factors ClfA, MntC, and capsule polysaccharide were detected by qRT-PCR. Antigen expression was indirectly confirmed by increases in antibody titer during the course of infection from acute to convalescent phase. Demonstration of bacterial transcript expression together with immunological response to the SA4Ag antigens in a clinically relevant patient population provides support for inclusion of these antigens in a prophylactic vaccine.

A randomized phase I study of the safety and immunogenicity of three ascending dose levels of a 3-antigen Staphylococcus aureus vaccine (SA3Ag) in healthy adults.

BACKGROUND: Staphylococcus aureus is a common cause of healthcare-acquired morbidity and mortality and increased healthcare resource utilization. A prophylactic vaccine is being developed that may reduce this disease burden. METHODS: Volunteers in good general health aged 50-85 (n=312) and 18-24 (n=96) years were randomized to receive a single intramuscular dose of one of three dose levels of a non-adjuvanted, 3-antigen S. aureus vaccine (SA3Ag) or placebo. SA3Ag antigens included capsular polysaccharides 5 and 8 (CP5 and CP8), each conjugated to cross-reactive material 197 (CRM197), and recombinant clumping factor A (ClfA). Safety, tolerability, and immunogenicity were evaluated. RESULTS: At day 29 post-vaccination, robust immune responses were observed in both age cohorts at all three SA3Ag dose levels. In the primary analysis population, the 50- to 85-year age stratum, geometric mean-fold-rises in competitive Luminex(®) immunoassay antibody titers from baseline ranged from 29.2 to 83.7 (CP5), 14.1 to 31.0 (CP8), and 37.1 to 42.9 (ClfA), all (P<0.001) exceeding the pre-defined two-fold rise criteria. Similar rises in opsonophagocytic activity assay titers demonstrated functionality of the immune response. Most injection-site reactions were mild in severity and there were no substantial differences (SA3Ag vs. placebo) with regard to systemic or adverse events. CONCLUSIONS: In this study of healthy adults aged 50-85 and 18-24 years, SA3Ag elicited a rapid and robust immune response and was well tolerated, with no notable safety concerns.

Immunogenicity and safety of 13-valent pneumococcal conjugate vaccine in Mexico.

OBJECTIVE: To assess the safety and immune responses induced by a 13-valent pneumococcal conjugate vaccine (PCV13) after immunization of infants in Mexico. METHODS: PCV13 was given with other routine childhood vaccinations to 225 infants in Mexico at ages 2, 4, 6, and 12 months. RESULTS: The proportions of subjects achieving immunoglobulin G (IgG) concentrations ≥0.35 µg/mL after the infant series and toddler dose were ≥93.1% and ≥96.7%, respectively, for all 13 serotypes. The serotype-specific pneumococcal IgG geometric mean concentrations after the infant series and toddler dose ranged from 1.18 to 9.13 µg/mL and from 1.62 to 15.41 µg/mL, respectively. The most common local reaction and systemic event after each dose were tenderness and irritability, respectively. Most fever was mild; no fever >40.0°C (i.e., severe) was reported. One subject withdrew because of Kawasaki disease 5 days after the first dose of vaccines, but this condition was not considered related to PCV13. CONCLUSIONS: Overall, PCV13 administered with routine pediatric vaccines was immunogenic and safe in healthy infants in Mexico.

Immunogenicity and safety of 13-valent pneumococcal conjugate vaccine in Mexico / Inmunogenia y seguridad de la vacuna antineumocócica conjugada 13 valente en México

OBJECTIVE: To assess the safety and immune responses induced by a 13-valent pneumococcal conjugate vaccine (PCV13) after immunization of infants in Mexico. METHODS: PCV13 was given with other routine childhood vaccinations to 225 infants in Mexico at ages 2, 4, 6, and 12 months. RESULTS: The proportions of subjects achieving immunoglobulin G (IgG) concentrations ≥0.35 µg/mL after the infant series and toddler dose were ≥93.1% and ≥96.7%, respectively, for all 13 serotypes. The serotype-specific pneumococcal IgG geometric mean concentrations after the infant series and toddler dose ranged from 1.18 to 9.13 µg/mL and from 1.62 to 15.41 µg/mL, respectively. The most common local reaction and systemic event after each dose were tenderness and irritability, respectively. Most fever was mild; no fever >40.0°C (i.e., severe) was reported. One subject withdrew because of Kawasaki disease 5 days after the first dose of vaccines, but this condition was not considered related to PCV13. CONCLUSIONS: Overall, PCV13 administered with routine pediatric vaccines was immunogenic and safe in healthy infants in Mexico.

OBJETIVO: Evaluar la seguridad y la respuesta inmunitaria inducida por una vacuna antineumocócica conjugada 13 valente (PCV13) tras la vacunación de lactantes en México. MÉTODOS: Se administró la PCV13, junto con otras vacunas habituales de la niñez, a 225 lactantes a los 2, 4, 6 y 12 meses de edad en México. RESULTADOS: Las proporciones de lactantes que alcanzaron concentraciones de inmunoglobulina G (IgG) iguales o superiores a 0,35 µg/ml después de las tres primeras dosis (serie del lactante) y tras la cuarta (dosis del inicio de la deambulación) fueron de ≥ 93,1% y ≥ 96,7%, respectivamente, para los 13 serotipos. Las medias geométricas de las concentraciones de IgG antineumocócica específica de serotipo después de las tres primeras dosis y tras la cuarta variaron de 1,18 a 9,13 µg/ml, y de 1,62 a 15,41 µg/ml, respectivamente. Las reacciones local y sistémica más frecuentes después de cada dosis fueron respectivamente el dolor en el punto de inyección y la irritabilidad. En la mayor parte de los casos, la fiebre fue de carácter leve; no se notificó ningún caso de fiebre de más de 40,0 °C (fiebre grave). Un lactante fue excluido del estudio como consecuencia de la aparición de una enfermedad de Kawasaki cinco días después de la primera dosis de la vacuna, aunque se consideró que este proceso no estaba relacionado con la PCV13. CONCLUSIONES: En términos generales, la PCV13, administrada conjuntamente con las vacunas pediátricas habituales, se mostró inmunógena e inocua en lactantes sanos de México.

Vaccine review: "Staphyloccocus aureus vaccines: problems and prospects".

Staphylococcus aureus is a leading cause of both healthcare- and community-associated infections globally. S. aureus exhibits diverse clinical presentations, ranging from benign carriage and superficial skin and soft tissue infections to deep wound and organ/space infections, biofilm-related prosthesis infections, life-threatening bacteremia and sepsis. This broad clinical spectrum, together with the high incidence of these disease manifestations and magnitude of the diverse populations at risk, presents a high unmet medical need and a substantial burden to the healthcare system. With the increasing propensity of S. aureus to develop resistance to essentially all classes of antibiotics, alternative strategies, such as prophylactic vaccination to prevent S. aureus infections, are actively being pursued in healthcare settings. Within the last decade, the S. aureus vaccine field has witnessed two major vaccine failures in phase 3 clinical trials designed to prevent S. aureus infections in either patients undergoing cardiothoracic surgery or patients with end-stage renal disease undergoing hemodialysis. This review summarizes the potential underlying reasons why these two approaches may have failed, and proposes avenues that may provide successful vaccine approaches to prevent S. aureus disease in the future.

Immunogenicity, safety and tolerability of 3 lots of 13-valent pneumococcal conjugate vaccine given with routine pediatric vaccinations in the United States.

BACKGROUND: The 7-valent pneumococcal conjugate vaccine (PCV7; serotypes 4, 6B, 9V, 14, 18C, 19F and 23F) has decreased invasive pneumococcal disease incidence. This study was performed to support licensure of a 13-valent pneumococcal conjugate vaccine (PCV13), which expands serotype coverage to include serotypes 1, 3, 5, 6A, 7F and 19A. This study assessed the immunogenicity, safety and manufacturing consistency of PCV13. METHODS: Randomized, double-blind, multicenter trial. Healthy United States infants were randomized 2:2:2:1 to receive 1 of 3 lots of PCV13 or PCV7, along with routine US pediatric vaccines at ages 2, 4 and 6 months (infant series), and 12 months (toddler dose). RESULTS: Among 1709 vaccinated infants, 1 month postinfant series and 1 month posttoddler dose, immunoglobulin G geometric mean concentrations (GMCs) were within 2-fold among the PCV13 lots, meeting equivalence criteria for all 13 serotypes. In a post hoc analysis, based on percent responders at ≥0.35 µg/mL postinfant series and immunoglobulin G GMC ratios postinfant series and posttoddler dose, noninferiority criteria were met for combined PCV13 lots compared with PCV7 for all common serotypes. Posttoddler dose immunoglobulin G GMCs were higher than postinfant series GMCs for all serotypes. Local reactions and fevers were generally mild; incidences of local reactions, systemic events and adverse events were generally similar between groups. CONCLUSIONS: PCV13 can be manufactured in a manner that elicits consistent immune responses. PCV13 provides increased serotype coverage and immunogenicity that is noninferior to PCV7 and has a safety profile similar to PCV7 when given with routine pediatric vaccines.

Antibody responses to routine pediatric vaccines administered with 13-valent pneumococcal conjugate vaccine.

BACKGROUND: A 13-valent pneumococcal conjugate vaccine (PCV13) has been licensed in >100 countries to broaden coverage against pneumococcal disease. We assessed whether PCV13 interferes with immune responses to concomitantly administered routine pediatric vaccines. METHODS: Healthy US infants were randomly assigned in 2 studies to receive PCV13 or 7-valent PCV (PCV7) at age 2, 4 and 6 months concomitantly with diphtheria, tetanus, acellular pertussis, inactivated polio virus, hepatitis B and Haemophilus influenzae type b, and at age 12-15 months with measles, mumps, rubella, varicella and hepatitus A. Antibodies to pertussis antigens, diphtheria, tetanus toxoid, poliovirus types 1-3, Haemophilus influenzae type b polyribosylribitol phosphate capsular polysaccharide and polyribosylribitol phosphate capsular polysaccharide were measured 1 month after the infant series; measles, mumps, rubella, varicella and polyribosylribitol phosphate capsular polysaccharide were determined 1 month after the toddler dose. Both the percentages of responders (subjects reaching a prespecified antibody concentration) and immunoglobulin G antibody geometric mean concentrations/titers were calculated for each concomitant vaccine antigen. RESULTS: Not all assays were performed on all subjects. Data were available from 153 to 239 infants and 163-230 toddlers in the PCV13 group and 173-240 infants and 167-214 toddlers in the PCV7 group. One month after both infant series and the toddler dose, noninferiority criteria were met for all antigens with respect to percentage of responders in both PCV7 and PCV13 groups. Immunoglobulin G antibody geometric mean concentration/titer ratios (PCV13/PCV7) were 0.91-1.33 and 0.83-1.03 at 1 month after the infant series and toddler dose, respectively, and met predetermined noninferiority criteria. CONCLUSIONS: Immune responses to routine pediatric vaccines concomitantly administered with PCV13 were noninferior to responses achieved when administered with PCV7.

A recombinant clumping factor A-containing vaccine induces functional antibodies to Staphylococcus aureus that are not observed after natural exposure.

Staphylococcus aureus is a Gram-positive pathogen that causes devastating disease and whose pathogenesis is dependent on interactions with host cell factors. Staphylococcal clumping factor A (ClfA) is a highly conserved fibrinogen (Fg)-binding protein and virulence factor that contributes to host tissue adhesion and initiation of infection. ClfA is being investigated as a possible component of a staphylococcal vaccine. We report the development of an Fg-binding assay that is specific for ClfA-mediated binding. Using the assay, we show that despite the presence of anti-ClfA antibodies, human sera from unvaccinated subjects are unable to prevent the binding of S. aureus to an Fg-coated surface. In contrast, antibodies elicited by a recombinant ClfA-containing vaccine were capable of blocking the ClfA-dependent binding of a diverse and clinically relevant collection of staphylococcal strains to Fg. These functional antibodies were also able to displace S. aureus already bound to Fg, suggesting that the ligand-binding activity of ClfA can be effectively neutralized through vaccination.

Safety and immunogenicity of a 13-valent pneumococcal conjugate vaccine in healthy infants and toddlers given with routine pediatric vaccinations in Canada.

BACKGROUND: The global distribution of pneumococcal disease and emergence of nonvaccine pneumococcal serotypes prompted the development of a 13-valent pneumococcal conjugate vaccine (PCV13), with broader coverage than 7-valent PCV (PCV7). This study compared compatibility of PCV13 and PCV7 with concurrently administered diphtheria, tetanus, acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b vaccine, and meningococcal C conjugate vaccine (menC), and assessed the safety and immunogenicity of PCV13. METHODS: In this double-blind, randomized trial, children received PCV7 or PCV13 at 2, 4, 6, and 12 months with routine vaccinations. One month following the infant series and toddler dose, the responses to Hib, pertussis, menC, and specific pneumococcal serotypes were measured. Safety and tolerability were assessed daily for 4 days by parents. RESULTS: Subjects received PCV13 (n = 300) or PCV7 (n = 303); immunogenicity assessment was completed in 265 and 268 subjects, respectively. There were no statistically significant differences between the groups in responses to Hib, pertussis, or menC after primary or booster vaccinations. More than 95% of subjects in the PCV13 group produced >0.35 µg/mL antibody to each pneumococcal serotype 1 month after the third dose, except with serotypes 23F (90%), 3 (80%), and 5 (87%). After the fourth dose, 98% to 100% of subjects achieved serotype-specific antibody concentrations >0.35 µg/mL, except for serotype 3 (85%). Safety and tolerability did not differ between groups with respect to local or systemic side effects. CONCLUSIONS: Responses to routine childhood vaccines did not differ with PCV7 or PCV13 coadministration. Serotype-specific pneumococcal antibody concentrations were protective. The safety profile of PCV13 was favorable.