BACKGROUND: Pertussis serodiagnosis is increasingly being used in the United States despite the lack of a US Food and Drug Administration-approved, commercially available assay. To better understand the utility of these assays in diagnosing pertussis, serology assays were evaluated for analytical parameters and clinical accuracy. METHODS: Forty-three antigen-antibody combinations were evaluated for single-point diagnosis of pertussis. Serum panels included sera from laboratory-confirmed cases, an international reference standard, and healthy donors. Phase I panel (n = 20) of sera was used to assess precision, linearity, and accuracy; Phase II panel (n = 226) followed with positive percent agreement (PPA) and negative percent agreement (NPA) estimates. Analytical analyses included coefficients of variation (CV) and concordance correlation coefficients (rc). RESULTS: Intra-analyst variability was found to be relatively low among samples per assay, with only 6% (78 of 1240) having CV >20%, primarily with the highly concentrated immunoglobulin (Ig)G anti-pertussis toxin (PT) specimens and IgM assays. The rc measurements to assess linearity ranged between 0.282 and 0.994, 0.332 and 0.999, and -0.056 and 0.482 for IgA, IgG, and IgM, respectively. Analytical accuracy for calibrated IgG anti-PT assays was 86%-115%. The PPA and NPA varied greatly for all assays; PPA/NPA ranges for IgA, IgG, and IgM assays, with culture and/or polymerase chain reaction positivity as control, were 29-90/13-100, 26-96/27-100, and 0-73/42-100, respectively. In IgG assays, mixing filamentous hemagglutinin antigen with PT increased PPA but decreased NPA. CONCLUSIONS: Seroassays varied substantially under both analytical and clinical parameters; however, those that were calibrated to a reference standard were highly accurate. Our findings support incorporation of calibrated pertussis seroassays to the pertussis case definition for improved diagnosis and surveillance.

Protective antigen (PA)-specific antibody and cell mediated immune (CMI) responses to annual and alternate booster schedules of Anthrax Vaccine Adsorbed (AVA, BioThrax(R)) were characterized in humans over 43 months. Study participants received 1 of 6 vaccination schedules: 3-dose intramuscular (IM) priming series (0, 1, 6 months) with a single booster at 42 months (4-IM); 3-dose IM priming with boosters at 18 and 42 months (5-IM); 3-dose IM priming with boosters at 12, 18, 30 and 42 months (7-IM); the 1970 licensed priming series of 6 doses (0, 0.5, 1, 6, 12, 18 months) and two annual boosters (30, 42 months) administered either subcutaneous (SQ) (8-SQ) or IM (8-IM); or saline placebo control at all eight time-points.Antibody response profiles included serum anti-PA IgG levels, subclass distributions, avidity, and lethal toxin neutralization activity (TNA). CMI profiles included frequencies of IFN-gamma and IL-4 secreting cells and memory B cells (MBCs), lymphocyte proliferation indices (SI) and induction of IFN-gamma, IL-2, IL-4, IL-6, IL-1beta and TNF-alpha mRNA levels.All active schedules elicited high avidity PA-specific IgG, TNA, MBCs and T cell responses with a mixed Th1/Th2 profile and Th2 dominance. Anti-PA IgG and TNA were highly correlated (e.g. Month 7, r2 = 0.86, p < 0.0001, log10 transformed) and declined in the absence of boosters. Boosters administered IM generated the highest antibody responses. Increasing time intervals between boosters generated faster and statistically superior antibody responses to the final Month 42 vaccination. CMI responses to the 3-dose IM priming remained elevated up to 43 Months.

BACKGROUND: A group A meningococcal conjugate vaccine, PsA-TT, was licensed in 2010 and was previously studied in a phase 2 clinical trial to evaluate its safety and immunogenicity in African children 12-23 months of age. METHODS: Subjects received either PsA-TT; meningococcal group A, C, W, Y polysaccharide vaccine (PsACWY); or Haemophilus influenzae type b conjugate vaccine (Hib-TT). Forty weeks following primary vaccination, the 3 groups were further randomized to receive either PsA-TT, one-fifth dose of PsACWY, or Hib-TT. Group A-specific immunoglobulin G (IgG) subclass response was characterized using an enzyme-linked immunosorbent assay. RESULTS: The predominant IgG subclass response, regardless of vaccine, was IgG1. One month following primary vaccination, the geometric mean concentrations (GMCs) of IgG1 and IgG2 in the PsA-TT group were 21.73 microg/mL and 6.27 microg/mL, whereas in the PsACWY group the mean GMCs were 2.01 microg/mL and 0.97 microg/mL, respectively (P < .0001). Group A-specific IgG1 and IgG2 GMCs remained greater in the PsA-TT group than in the PsACWY group 40 weeks following primary vaccination (P < .0001). One week following revaccination, those given 2 doses of PsA-TT had the greatest IgG1 and IgG2 GMCs of 125.23 microg/mL and 36.12 microg/mL, respectively (P = .0008), and demonstrated a significant increase in IgG1:IgG2 mean ratio, indicative of the T-cell-dependent response associated with conjugate vaccines. CONCLUSIONS: Vaccination of African children aged 12-24 months with either PsA-TT or PsACWY elicited a predominantly IgG1 response. The IgG1:IgG2 mean ratio decreased following successive vaccination with PsACWY, indicating a shift toward IgG2, suggestive of the T-cell-independent immune response commonly associated with polysaccharide antigens. CLINICAL TRIALS REGISTRATION: SRCTN78147026.

BACKGROUND: A safe, affordable, and highly immunogenic meningococcal A conjugate vaccine (PsA-TT, MenAfriVac) was developed to control epidemic group A meningitis in Africa. Documentation of the safety specifications of the PsA-TT vaccine was warranted, with sufficient exposure to detect potential rare vaccine-related adverse reactions. METHODS: This phase 3, double-blind, randomized, active controlled clinical study was designed to evaluate the safety-primarily vaccine-related serious adverse events (SAEs)-up to 3 months after administration of a single dose of the PsA-TT vaccine to subjects aged 1-29 years in Mali. Safety outcomes were also compared to those following a single dose of a licensed meningococcal ACWY polysaccharide vaccine (PsACWY). RESULTS: No vaccine-related SAEs occurred during the 3 months of follow-up of 4004 subjects vaccinated with a single dose of PsA-TT. When compared to PsACWY (1996 subjects), tenderness at the injection site appeared to be more frequent in the PsA-TT group. However, rates of local induration, systemic reactions, adverse events (AEs), and SAEs were similar in both groups, and unsolicited AEs and SAEs were all unrelated to the study vaccines. CONCLUSIONS: The study confirmed on a large scale the excellent safety profile of a single dose of PsA-TT when administered to its entire target population of 1-29 years of age.

BACKGROUND: PsA-TT (MenAfriVac) is a conjugated polysaccharide vaccine developed to eliminate group A meningococcal disease in Africa. Vaccination of African study participants with 1 dose of PsA-TT led to the production of anti-A polysaccharide antibodies and increased serum bactericidal activity measured using rabbit complement (rSBA). Bactericidal responses measured with human complement (hSBA) are presented here. METHODS: Sera collected before and at 28 days and 1 year after vaccination with either PsA-TT or quadrivalent polysaccharide vaccine (PsACWY) from a random, age-distributed 360-subject subset of the Meningitis Vaccine Project study of PsA-TT in Africans aged 2-29 years were tested for hSBA. Geometric mean titer, fold-rise, and threshold analyses were compared between vaccine groups and age groups. hSBA, rSBA, and immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) results were compared and assay correlation and agreement determined. RESULTS: hSBA responses to PsA-TT were substantially higher than those to PsACWY at 28 days and 1 year following immunization, similar to previously reported rSBA and IgG results. The hSBA and IgG ELISA results identified differences between age groups that were not evident by rSBA. The rSBA data indicated sustained high titers 1 year after immunization, whereas hSBA GMTs at 1 year approached 4 in young children. CONCLUSIONS: The high level of protection following PsA-TT immunization campaigns is consistent with the strong hSBA immune responses observed here. Future implementation decisions will likely depend on immunologic data and their long-term correlation with disease and carriage prevention. Expanded immunologic and epidemiologic surveillance may improve the interpretation of differences between these immunoassays.

BACKGROUND: Yellow fever (YF) is still a major public health problem in endemic regions of Africa and South America. In Africa, one of the main control strategies is routine vaccination within the Expanded Programme on Immunization (EPI). A new meningococcal A conjugate vaccine (PsA-TT) is about to be introduced in the EPI of countries in the African meningitis belt, and this study reports on the immunogenicity of the YF-17D vaccines in infants when administered concomitantly with measles vaccine and PsA-TT. METHODS: Two clinical studies were conducted in Ghana and in Mali among infants who received PsA-TT concomitantly with measles and YF vaccines at 9 months of age. YF neutralizing antibody titers were measured using a microneutralization assay. RESULTS: In both studies, the PsA-TT did not adversely affect the immune response to the concomitantly administered YF vaccine at the age of 9 months. The magnitude of the immune response was different between the 2 studies, with higher seroconversion and seroprotection rates found in Mali vs Ghana. CONCLUSIONS: Immunogenicity to YF vaccine is unaffected when coadministered with PsA-TT at 9 months of age. Further studies are warranted to better understand the determinants of the immune response to YF vaccine in infancy..

BACKGROUND: A meningococcal group A conjugate vaccine, PsA-TT (MenAfriVac), developed through the Meningitis Vaccine Project and manufactured by the Serum Institute of India, Ltd, was tested in multiple clinical trials conducted mainly in Africa. The impact of age at which subjects were vaccinated on immune response and persistence postimmunization with PsA-TT was the main focus of the current analysis. METHODS: Subjects who were vaccinated with a single dose of 10 microg of PsA-TT at 12-23 months or 22-33 months of age in study A conducted in Mali and The Gambia; at 2-10 years, 11-17 years, or 18-29 years of age in study B conducted in Mali, The Gambia, and Senegal; and at 14-18 weeks, 9-12 months, or 12-18 months of age in study C conducted in Ghana are included in the current analysis. Immunogenicity was measured by group A serum bactericidal antibody (SBA) titer with baby rabbit complement. RESULTS: Significant differences in SBA titers were found among the age groups in studies B and C both 28 days and 1 year postimmunization. A significant difference in SBA titers between age groups 12-23 months and 22-33 months was only observed 1 year postimmunization in study A. Antibody titers remained at similar levels from 1 to 2 years postimmunization for subjects vaccinated at 12-23 months in study A and at 9-12 months or 12-18 months of age in study C. CONCLUSIONS: Subjects immunized at different ages had different postimmunization immune responses as measured by SBA titers. Toddlers tended to have higher immune responses than infants. This pattern persisted at least 1 year postimmunization.

BACKGROUND: Following mass vaccination campaigns in the African meningitis belt with group A meningococcal conjugate vaccine, MenAfriVac (PsA-TT), disease due to group A meningococci has nearly disappeared. Antibody persistence in healthy African toddlers was investigated. METHODS: African children vaccinated at 12-23 months of age with PsA-TT were followed for evaluation of antibody persistence up to 5 years after primary vaccination. Antibody persistence was evaluated by measuring group A serum bactericidal antibody (SBA) with rabbit complement and by a group A-specific IgG enzyme-linked immunosorbent assay (ELISA). RESULTS: Group A antibodies measured by SBA and ELISA were shown to decline in the year following vaccination and plateaued at levels significantly above baseline for up to 5 years following primary vaccination. CONCLUSIONS: A single dose of PsA-TT induces long-term sustained levels of group A meningococcal antibodies for up to 5 years after vaccination.

BACKGROUND: Mass vaccination campaigns of the population aged 1-29 years with 1 dose of group A meningococcal (MenA) conjugate vaccine (PsA-TT, MenAfriVac) in African meningitis belt countries has resulted in the near-disappearance of MenA. The vaccine was tested in clinical trials in Africa and in India and found to be safe and highly immunogenic compared with the group A component of the licensed quadrivalent polysaccharide vaccine (PsACWY). Antibody persistence in Africa and in India was investigated. METHODS: A total of 900 subjects aged 2-29 years were followed up for 4 years in Senegal, Mali, and The Gambia (study A). A total of 340 subjects aged 2-10 years were followed up for 1 year in India (study B). In study A, subjects were randomized in a 2:1 ratio, and in study B a 1:1 ratio to receive either PsA-TT or PsACWY. Immunogenicity was evaluated by measuring MenA serum bactericidal antibody (SBA) with rabbit complement and by a group A-specific immunoglobulin G (IgG) enzyme-linked immunosorbent assay. RESULTS: In both studies, substantial SBA decay was observed at 6 months postvaccination in both vaccine groups, although more marked in the PsACWY group. At 1 year and 4 years (only for study A) postvaccination, SBA titers were relatively sustained in the PsA-TT group, whereas a slight increasing trend, more pronounced among the youngest, was observed in the participants aged <18 years in the PsACWY groups. The SBA titers were significantly higher in the PsA-TT group than in the PsACWY group at any time point, and the majority of subjects in the PsA-TT group had SBA titers ≥128 and group A-specific IgG concentrations ≥2 microg/mL at any point in time in both the African and Indian study populations. CONCLUSIONS: Four years after vaccination with a single dose of PsA-TT vaccine in Africa, most subjects are considered protected from MenA disease. CLINICAL TRIALS REGISTRATION: PsA-TT-003 (ISRCTN87739946); PsA-TT-003a (ISRCTN46335400).

BACKGROUND: Integrated Management of Childhood Illness (IMCI) guidelines were developed to decrease morbidity and mortality, yet implementation varies across settings. Factors associated with poor adherence are not well understood. METHODS: We used data from Manhica District Hospital outpatient department and five peripheral health centers to examine pneumonia management for children <5 years old from January 2008 to June 2011. Episodes of IMCI-defined pneumonia (cough or difficult breathing plus tachypnea), severe pneumonia (pneumonia plus chest wall in-drawing), and/or clinician-diagnosed pneumonia (based on discharge diagnosis) were included. RESULTS: Among severe pneumonia episodes, 96.2% (2,918/3,032) attended in the outpatient department and 70.0% (291/416) attended in health centers were appropriately referred to the emergency department. Age<1 year, malnutrition and various physical exam findings were associated with referral. For non-severe pneumonia episodes, antibiotics were prescribed in 45.7% (16,094/35,224). Factors associated with antibiotic prescription included age <1 year, abnormal auscultatory findings, and clinical diagnosis of pneumonia; diagnosis of malaria or gastroenteritis and pallor were negatively associated with antibiotic prescription. CONCLUSION: Adherence to recommended management of severe pneumonia was high in a hospital outpatient department, but suboptimal in health centers. Antibiotics were prescribed in fewer than half of non-severe pneumonia episodes, and diagnosis of malaria was the strongest risk factor for incorrect management.

Humoral and cell mediated immune correlates of protection (COP) for inhalation anthrax in a rhesus macaque (Macaca mulatta) model were determined. Immunological and survival data were from 114 vaccinated and 23 control animals exposed to Bacillus anthracis spores at 12, 30 or 52 months after the first vaccination. Vaccinated animals received a 3-dose intramuscular priming series (0, 1, 6 months; 3-IM) of anthrax vaccine adsorbed (AVA, BioThrax). Immune responses were modulated by administering a range of vaccine dilutions. Together with vaccine dilution dose and the interval between first vaccination and challenge, each of 80 immune response variables to anthrax toxin protective antigen (PA) at every available study time point was analyzed as a potential COP by logistic regression penalized by Least Absolute Shrinkage and Selection Operator (LASSO) or elastic net. Anti-PA IgG at the last available time point before challenge ('Last') and lymphocyte stimulation index (SI) at months 2 and 6 were identified consistently as COP. Anti-PA IgG and lethal toxin neutralization activity (TNA) at month 6 and month 7 ('Peak') and the frequency of IFN-gamma secreting cells at month 6 also had statistically significant positive correlations with survival. The ratio of IL-4 mRNA to IFN-gamma mRNA at month 6 also had a statistically significant correlation with survival. TNA had lower COP accuracy than anti-PA IgG. Following 3-IM priming with AVA, the anti-PA IgG responses at the time of exposure or at month 7 were practicable and accurate metrics for correlating vaccine induced immunity with protection against inhalation anthrax.

Serogroup C meningococcal (MenC) disease accounts for one-third of all meningococcal cases and causes meningococcal outbreaks in the U.S. Quadrivalent meningococcal vaccine conjugated to diphtheria toxoid (MenACYWD) was recommended in 2005 for adolescents and high risk groups such as military recruits. We evaluated anti-MenC antibody persistence in U.S. military personnel vaccinated with either MenACYWD or meningococcal polysaccharide vaccine (MPSV4). Twelve hundred subjects vaccinated with MenACYWD from 2006 to 2008 or MPSV4 from 2002 to 2004 were randomly selected from the Defense Medical Surveillance System. Baseline serologic responses to MenC were assessed in all subjects; 100 subjects per vaccine group were tested during one of the following six post-vaccination time-points: 5-7, 11-13, 17-19, 23-25, 29-31, or 35-37 months. Anti-MenC geometric mean titers (GMT) were measured by rabbit complement serum bactericidal assay (rSBA) and geometric mean concentrations (GMC) by enzyme-linked immunosorbent assay (ELISA). Continuous variables were compared using the Wilcoxon rank sum test and the proportion of subjects with an rSBA titer ≥8 by chi-square. Pre-vaccination rSBA GMT was <8 for the MenACWYD group. rSBA GMT increased to 703 at 5-7 months post-vaccination and decreased by 94% to 43 at 3 years post-vaccination. GMT was significantly lower in the MenACWYD group at 5-7 months post-vaccination compared to the MPSV4 group. The percentage of MenACWYD recipients achieving an rSBA titer of ≥8 decreased from 87% at 5-7 months to 54% at 3 years. There were no significant differences between vaccine groups in the proportion of subjects with a titer of ≥8 at any time-point. GMC for the MenACWYD group was 0.14mug/mL at baseline, 1.07mug/mL at 5-7 months, and 0.66mug/mL at 3 years, and significantly lower than the MPSV4 group at all time-points. Anti-MenC responses wane following vaccination with MenACYWD; a booster dose is needed to maintain protective levels of circulating antibody.

OBJECTIVE: We evaluated an alternative administration route, reduced schedule priming series, and increased intervals between booster doses for anthrax vaccine adsorbed (AVA). AVA's originally licensed schedule was 6 subcutaneous (SQ) priming injections administered at months (m) 0, 0.5, 1, 6, 12 and 18 with annual boosters; a simpler schedule is desired. METHODS: Through a multicenter randomized, double blind, non-inferiority Phase IV human clinical trial, the originally licensed schedule was compared to four alternative and two placebo schedules. 8-SQ group participants received 6 SQ injections with m30 and m42 "annual" boosters; participants in the 8-IM group received intramuscular (IM) injections according to the same schedule. Reduced schedule groups (7-IM, 5-IM, 4-IM) received IM injections at m0, m1, m6; at least one of the m0.5, m12, m18, m30 vaccine doses were replaced with saline. All reduced schedule groups received a m42 booster. Post-injection blood draws were taken two to four weeks following injection. Non-inferiority of the alternative schedules was compared to the 8-SQ group at m2, m7, and m43. Reactogenicity outcomes were proportions of injection site and systemic adverse events (AEs). RESULTS: The 8-IM group's m2 response was non-inferior to the 8-SQ group for the three primary endpoints of anti-protective antigen IgG geometric mean concentration (GMC), geometric mean titer, and proportion of responders with a 4-fold rise in titer. At m7 anti-PA IgG GMCs for the three reduced dosage groups were non-inferior to the 8-SQ group GMCs. At m43, 8-IM, 5-IM, and 4-IM group GMCs were superior to the 8-SQ group. Solicited injection site AEs occurred at lower proportions in the IM group compared to SQ. Route of administration did not influence the occurrence of systemic AEs. A 3 dose IM priming schedule with doses administered at m0, m1, and m6 elicited long term immunological responses and robust immunological memory that was efficiently stimulated by a single booster vaccination at 42 months. CONCLUSIONS: A priming series of 3 intramuscular doses administered at m0, m1, and m6 with a triennial booster was non-inferior to more complex schedules for achieving antibody response.

BACKGROUND: College students living in residential halls are at increased risk of meningococcal disease. Unlike for serogroups prevented by quadrivalent meningococcal vaccines, public health response to outbreaks of serogroup B meningococcal disease is limited by lack of a US licensed vaccine. METHODS: In March 2010 we investigated a prolonged outbreak of serogroup B disease associated with a university. In addition to case ascertainment, molecular typing of isolates was performed to characterize the outbreak. We conducted a matched case-control study to examine risk factors for serogroup B disease. Five controls per case, matched by college year, were randomly selected. Participants completed a risk factor questionnaire. Data were analyzed using conditional logistic regression. RESULTS: Between January 2008 and November 2010, we identified 13 meningococcal disease cases (seven confirmed, four probable, and two suspected) among university students (ten) or university-linked persons (three). One student died. Ten cases were determined to be serogroup B. Isolates from six confirmed cases had an indistinguishable pulse-field gel electrophoresis pattern and belonged to sequence type ST-269, clonal complex 269. Factors significantly associated with disease were Greek Society membership (matched odds ratio [mOR] 15.0; p=0.03), >1 kissing partner (mOR 13.7; p=0.03) and attending bars (mOR 8.1; p=0.04). CONCLUSIONS: The outbreak was associated with a novel serogroup B strain (CC269) and risk factors indicative of increased social mixing. Control measures were appropriate but limited by lack of vaccine. Understanding serogroup B transmission in college and other settings will help inform use of serogroup B vaccines currently under consideration for licensure.

BACKGROUND: Although cerebrospinal fluid (CSF) culture is the diagnostic reference standard for bacterial meningitis, its sensitivity is limited, particularly when antibiotics were previously administered. CSF Gram staining and real-time PCR are theoretically less affected by antibiotics; however, it is difficult to evaluate these tests with an imperfect reference standard. METHODS AND FINDINGS: CSF from patients with suspected meningitis from Salvador, Brazil were tested with culture, Gram stain, and real-time PCR using S. pneumoniae, N. meningitidis, and H. influenzae specific primers and probes. An antibiotic detection disk bioassay was used to test for the presence of antibiotic activity in CSF. The diagnostic accuracy of tests were evaluated using multiple methods, including direct evaluation of Gram stain and real-time PCR against CSF culture, evaluation of real-time PCR against a composite reference standard, and latent class analysis modeling to evaluate all three tests simultaneously. RESULTS: Among 451 CSF specimens, 80 (17.7%) had culture isolation of one of the three pathogens (40 S. pneumoniae, 36 N. meningitidis, and 4 H. influenzae), and 113 (25.1%) were real-time PCR positive (51 S. pneumoniae, 57 N. meningitidis, and 5 H. influenzae). Compared to culture, real-time PCR sensitivity and specificity were 95.0% and 90.0%, respectively. In a latent class analysis model, the sensitivity and specificity estimates were: culture, 81.3% and 99.7%; Gram stain, 98.2% and 98.7%; and real-time PCR, 95.7% and 94.3%, respectively. Gram stain and real-time PCR sensitivity did not change significantly when there was antibiotic activity in the CSF. CONCLUSION: Real-time PCR and Gram stain were highly accurate in diagnosing meningitis caused by S. pneumoniae, N. meningitidis, and H. influenzae, though there were few cases of H. influenzae. Furthermore, real-time PCR and Gram staining were less affected by antibiotic presence and might be useful when antibiotics were previously administered. Gram staining, which is inexpensive and commonly available, should be encouraged in all clinical settings.

The meningococcal antigen typing system (MATS) sandwich enzyme-linked immunosorbent assay (ELISA) was designed to measure the immunologic cross-reactivity and quantity of antigens in target strains of a pathogen. It was first used to measure the factor H-binding protein (fHbp), neisserial adhesin A (NadA), and neisserial heparin-binding antigen (NHBA) content of serogroup B meningococcal (MenB) isolates relative to a reference strain, or "relative potency" (RP). With the PorA genotype, the RPs were then used to assess strain coverage by 4CMenB, a multicomponent MenB vaccine. In preliminary studies, MATS accurately predicted killing in the serum bactericidal assay using human complement, an accepted correlate of protection for meningococcal vaccines. A study across seven laboratories assessed the reproducibility of RPs for fHbp, NadA, and NHBA and established qualification parameters for new laboratories. RPs were determined in replicate for 17 MenB reference strains at laboratories A to G. The reproducibility of RPs among laboratories and against consensus values across laboratories was evaluated using a mixed-model analysis of variance. Interlaboratory agreement was very good; the Pearson correlation coefficients, coefficients of accuracy, and concordance correlation coefficients exceeded 99%. The summary measures of reproducibility, expressed as between-laboratory coefficients of variation, were 7.85% (fHbp), 16.51% (NadA), and 12.60% (NHBA). The overall within-laboratory measures of variation adjusted for strain and laboratory were 19.8% (fHbp), 28.8% (NHBA), and 38.3% (NadA). The MATS ELISA was successfully transferred to six laboratories, and a further laboratory was successfully qualified.

A 3 dose (0, 1, 6 months) intramuscular (3-IM) priming series of a human dose (HuAVA) and dilutions up to 1:10 of anthrax vaccine adsorbed (AVA) provided statistically significant levels of protection (60-100%) against inhalation anthrax for up to 4 years in rhesus macaques.Serum anti-protective antigen (PA) IgG and lethal toxin neutralization activity (TNA) were detectable following a single injection of HuAVA or 1:5 AVA, or two injections of diluted vaccine (1:10, 1:20, 1:40 AVA). Anti-PA and TNA were highly correlated (overall r(2) = 0.89 for log(10) transformed data). Peak responses were at 6.5 months (mo). In general, with the exception of animals receiving 1:40 AVA, serum anti-PA and TNA responses remained significantly above control levels at 28.5mo (last time point measured for 1:20 AVA) and through 50.5mo in HuAVA, 1:5 and 1:10 AVA groups (p <0.05).PA-specific IFN-gamma and IL-4 CD4(+) cell frequencies and T cell stimulation indices were sustained to 50.5mo (last time point measured). PA-specific memory B cell frequencies were highly variable, but in general were detectable in PBMC by 2mo, significantly above controls by 7mo, and remained detectable in the HuAVA, 1:5 and 1:20 AVA groups to 42mo (last time point measured).HuAVA and diluted AVA elicited a combined Th1/Th2 response and robust immunological priming with sustained production of high avidity PA-specific functional antibody, long term immune cell competence and immunological memory (30mo for 1:20 AVA; 52mo for 1:10 AVA). Vaccinated animals surviving inhalation anthrax developed high magnitude anamnestic anti-PA IgG and TNA responses.

Lot 89SF has been the reference standard serum pool used in pneumococcal enzyme-linked immunosorbent assays (ELISAs) since 1990. In 2005, it was estimated that there remained between 2 and 5 years' supply of lot 89SF. Since lot 89SF was the reference standard used in the evaluation of the seven-valent pneumococcal conjugate vaccine Prevnar (PCV7), the link to clinical efficacy would be severed if stocks became completely depleted. Furthermore, demonstration of immune responses comparable to those elicited by PCV7 is a licensure approach used for new pneumococcal conjugate vaccines, so a replacement reference standard was required. A total of 278 volunteers were immunized with the 23-valent unconjugated polysaccharide vaccine Pneumovax II, and a unit of blood was obtained twice within 120 days following immunization. Plasma was prepared, pooled, and confirmed to be free from hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV. The pooled serum was poured at 6 ml per vial into 15,333 vials and lyophilized. Immunological bridging of 007sp to 89SF was used to establish equivalent reference values for 13 pneumococcal capsular serotypes (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F and 23F) by five independent laboratories. Antibody concentrations in 007sp were established relative to the lot 89SF reference preparation using the WHO reference ELISA. Subsequently, 12 existing WHO calibration sera had concentrations reassigned for 13 pneumococcal serotypes using new serum 007sp as the reference, and these were compared to concentrations relative to the original reference serum. Agreement was excellent for the 12 WHO calibration sera. The 007sp preparation has replaced 89SF as the pneumococcal reference standard. Sufficient quantity of this new preparation is available such that, with judicious use, it should be available for at least 25 years.

BACKGROUND: Group A meningococci are the source of major epidemics of meningitis in Africa. An affordable, highly immunogenic meningococcal A conjugate vaccine is needed. METHODS: We conducted two studies in Africa to evaluate a new MenA conjugate vaccine (PsA-TT). In study A, 601 children, 12 to 23 months of age, were randomly assigned to receive PsA-TT, a quadrivalent polysaccharide reference vaccine (PsACWY), or a control vaccine (Haemophilus influenzae type b conjugate vaccine [Hib-TT]). Ten months later, these children underwent another round of randomization within each group to receive a full dose of PsA-TT, a one-fifth dose of PsACWY, or a full dose of Hib-TT, with 589 of the original participants receiving a booster dose. In study B, 900 subjects between 2 and 29 years of age were randomly assigned to receive PsA-TT or PsACWY. Safety and reactogenicity were evaluated, and immunogenicity was assessed by measuring the activity of group A serum bactericidal antibody (SBA) with rabbit complement and performing an IgG group A-specific enzyme-linked immunosorbent assay. RESULTS: In study A, 96.0% of the subjects in the PsA-TT group and 63.7% of those in the PsACWY group had SBA titers that were at least four times as high as those at baseline; in study B, 78.2% of the subjects in the PsA-TT group and 46.2% of those in the PsACWY group had SBA titers that were at least four times as high as those at baseline. The geometric mean SBA titers in the PsA-TT groups in studies A and B were greater by factors of 16 and 3, respectively, than they were in the PsACWY groups (P<0.001). In study A, the PsA-TT group had higher antibody titers at week 40 than the PsACWY group and had obvious immunologic memory after receiving a polysaccharide booster vaccine. Safety profiles were similar across vaccine groups, although PsA-TT recipients were more likely than PsACWY recipients to have tenderness and induration at the vaccination site. Adverse events were consistent with age-specific morbidity in the study areas; no serious vaccine-related adverse events were reported. CONCLUSIONS: The PsA-TT vaccine elicited a stronger response to group A antibody than the PsACWY vaccine. (Funded by the Meningitis Vaccine Project through a grant from the Bill and Melinda Gates Foundation; Controlled-Trials.com numbers, ISRCTN78147026 and ISRCTN87739946.).

Antibody mediated killing of Streptococcus pneumoniae (pneumococcus) by phagocytes is an important mechanism of protection of the human host against pneumococcal infections. Measurement of opsonophagocytic antibodies using a standardized opsonophagocytic assay (OPA) is important for the evaluation of candidate vaccines and a requirement for the licensure of new pneumococcal conjugate vaccine formulations. We assessed agreement among six laboratories that used their own optimized OPAs on a panel of 16 human reference sera for 13 pneumococcal serotypes. Consensus titers, estimated using an analysis of variance (ANOVA) mixed-effects model, provided a common reference to assess agreement among these laboratories. Agreement was evaluated using assay accuracy, reproducibility, repeatability, precision and bias. We also reviewed four acceptance criteria intervals for assessing the comparability of protocols when assaying the same reference sera. The precision, accuracy and concordance results among laboratories and the consensus titers revealed acceptable agreement. Results of this study indicate that the bioassays evaluated in this study are robust and the resultant OPA values are reproducible for the determination of functional antibody titers specific to 13 pneumococcal serotypes when performed by laboratories using highly standardized but not identical assays. The statistical methodologies employed in this study may serve as a template to evaluate future multilaboratory studies.

OBJECTIVES: We examined associations between the socioeconomic characteristics of census tracts and racial/ethnic disparities in the incidence of bacteremic community-acquired pneumonia among US adults. METHODS: We analyzed data on 4870 adults aged 18 years or older with community-acquired bacteremic pneumonia identified through active, population-based surveillance in 9 states and geocoded to census tract of residence. We used data from the 2000 US Census to calculate incidence by age, race/ethnicity, and census tract characteristics and Poisson regression to estimate rate ratios (RRs) and 95% confidence intervals (CIs). RESULTS: During 2003 to 2004, the average annual incidence of bacteremic pneumonia was 24.2 episodes per 100000 Black adults versus 10.1 per 100000 White adults (RR=2.40; 95% CI=2.24, 2.57). Incidence among Black residents of census tracts with 20% or more of persons in poverty (most impoverished) was 4.4 times the incidence among White residents of census tracts with less than 5% of persons in poverty (least impoverished). Racial disparities in incidence were reduced but remained significant in models that controlled for age, census tract poverty level, and state. CONCLUSIONS: Adults living in impoverished census tracts are at increased risk of bacteremic pneumonia and should be targeted for prevention efforts. (Am J Public Health. Published online ahead of print August 19, 2010: e1-e8. doi:10.2105/AJPH.2009.181313).

Systemic anthrax manifests as toxemia, rapidly disseminating septicemia, immune collapse, and death. Virulence factors include the anti-phagocytic gamma-linked poly-d-glutamic acid (PGA) capsule and two binary toxins, complexes of protective antigen (PA) with lethal factor (LF) and edema factor. We report the characterization of LF, PA, and PGA levels during the course of inhalation anthrax in five rhesus macaques. We describe bacteremia, blood differentials, and detection of the PA gene (pagA) by PCR analysis of the blood as confirmation of infection. For four of five animals tested, LF exhibited a triphasic kinetic profile. LF levels (mean +/- standard error [SE] between animals) were low at 24 h postchallenge (0.03 +/- 1.82 ng/ml), increased at 48 h to 39.53 +/- 0.12 ng/ml (phase 1), declined at 72 h to 13.31 +/- 0.24 ng/ml (phase 2), and increased at 96 h (82.78 +/- 2.01 ng/ml) and 120 h (185.12 +/- 5.68 ng/ml; phase 3). The fifth animal had an extended phase 2. PGA levels were triphasic; they were nondetectable at 24 h, increased at 48 h (2,037 +/- 2 ng/ml), declined at 72 h (14 +/- 0.2 ng/ml), and then increased at 96 h (3,401 +/- 8 ng/ml) and 120 h (6,004 +/- 187 ng/ml). Bacteremia was also triphasic: positive at 48 h, negative at 72 h, and positive at euthanasia. Blood neutrophils increased from preexposure (34.4% +/- 0.13%) to 48 h (75.6% +/- 0.08%) and declined at 72 h (62.4% +/- 0.05%). The 72-h declines may establish a "go/no go" turning point in infection, after which systemic bacteremia ensues and the host's condition deteriorates. This study emphasizes the value of LF detection as a tool for early diagnosis of inhalation anthrax before the onset of fulminant systemic infection.