Understanding the Chemistry and Biology of Glycosylation with Glycan Synthesis.

Glycoscience research has been significantly impeded by the complex compositions of the glycans present in biological molecules and the lack of convenient tools suitable for studying the glycosylation process and its function. Polysaccharides and glycoconjugates are not encoded directly by genes; instead, their biosynthesis relies on the differential expression of carbohydrate enzymes, resulting in heterogeneous mixtures of glycoforms, each with a distinct physiological activity. Access to well-defined structures is required for functional study, and this has been provided by chemical and enzymatic synthesis and by the engineering of glycosylation pathways. This review covers general methods for preparing glycans commonly found in mammalian systems and applying them to the synthesis of therapeutically significant glycoconjugates (glycosaminoglycans, glycoproteins, glycolipids, glycosylphosphatidylinositol-anchored proteins) and the development of carbohydrate-based vaccines.

Immunogenicity, reactogenicity, and IgE-mediated immune responses of a mixed whole-cell and acellular pertussis vaccine schedule in Australian infants: A randomised, double-blind, noninferiority trial.

BACKGROUND: In many countries, infant vaccination with acellular pertussis (aP) vaccines has replaced use of more reactogenic whole-cell pertussis (wP) vaccines. Based on immunological and epidemiological evidence, we hypothesised that substituting the first aP dose in the routine vaccination schedule with wP vaccine might protect against IgE-mediated food allergy. We aimed to compare reactogenicity, immunogenicity, and IgE-mediated responses of a mixed wP/aP primary schedule versus the standard aP-only schedule. METHODS AND FINDINGS: OPTIMUM is a Bayesian, 2-stage, double-blind, randomised trial. In stage one, infants were assigned (1:1) to either a first dose of a pentavalent wP combination vaccine (DTwP-Hib-HepB, Pentabio PT Bio Farma, Indonesia) or a hexavalent aP vaccine (DTaP-Hib-HepB-IPV, Infanrix hexa, GlaxoSmithKline, Australia) at approximately 6 weeks old. Subsequently, all infants received the hexavalent aP vaccine at 4 and 6 months old as well as an aP vaccine at 18 months old (DTaP-IPV, Infanrix-IPV, GlaxoSmithKline, Australia). Stage two is ongoing and follows the above randomisation strategy and vaccination schedule. Ahead of ascertainment of the primary clinical outcome of allergist-confirmed IgE-mediated food allergy by 12 months old, here we present the results of secondary immunogenicity, reactogenicity, tetanus toxoid IgE-mediated immune responses, and parental acceptability endpoints. Serum IgG responses to diphtheria, tetanus, and pertussis antigens were measured using a multiplex fluorescent bead-based immunoassay; total and specific IgE were measured in plasma by means of the ImmunoCAP assay (Thermo Fisher Scientific). The immunogenicity of the mixed schedule was defined as being noninferior to that of the aP-only schedule using a noninferiority margin of 2/3 on the ratio of the geometric mean concentrations (GMR) of pertussis toxin (PT)-IgG 1 month after the 6-month aP. Solicited adverse reactions were summarised by study arm and included all children who received the first dose of either wP or aP. Parental acceptance was assessed using a 5-point Likert scale. The primary analyses were based on intention-to-treat (ITT); secondary per-protocol (PP) analyses were also performed. The trial is registered with ANZCTR (ACTRN12617000065392p). Between March 7, 2018 and January 13, 2020, 150 infants were randomised (75 per arm). PT-IgG responses of the mixed schedule were noninferior to the aP-only schedule at approximately 1 month after the 6-month aP dose [GMR = 0·98, 95% credible interval (0·77 to 1·26); probability (GMR > 2/3) > 0·99; ITT analysis]. At 7 months old, the posterior median probability of quantitation for tetanus toxoid IgE was 0·22 (95% credible interval 0·12 to 0·34) in both the mixed schedule group and in the aP-only group. Despite exclusions, the results were consistent in the PP analysis. At 6 weeks old, irritability was the most common systemic solicited reaction reported in wP (65 [88%] of 74) versus aP (59 [82%] of 72) vaccinees. At the same age, severe systemic reactions were reported among 14 (19%) of 74 infants after wP and 8 (11%) of 72 infants after aP. There were 7 SAEs among 5 participants within the first 6 months of follow-up; on blinded assessment, none were deemed to be related to the study vaccines. Parental acceptance of mixed and aP-only schedules was high (71 [97%] of 73 versus 69 [96%] of 72 would agree to have the same schedule again). CONCLUSIONS: Compared to the aP-only schedule, the mixed schedule evoked noninferior PT-IgG responses, was associated with more severe reactions, but was well accepted by parents. Tetanus toxoid IgE responses did not differ across the study groups. TRIAL REGISTRATION: Trial registered at the Australian and New Zealand Clinical 207 Trial Registry (ACTRN12617000065392p).

Epidemiological and bacterial profile of childhood meningitis in Tunisia.

The worldwide burden of disease of bacterial meningitis remains high, despite the decreasing incidence following introduction of routine vaccination campaigns.The aim of our study was to evaluate the epidemiological and bacteriological profile of paediatric bacterial meningitis (BM) in Tunisian children, during the period 2003-2019, following the implementation of Haemophilus influenzae type b (Hib) vaccine (April 2011) and before 10-valent pneumoccocal conjugate vaccine (PCV10) introduction to the childhood immunization program.All bacteriologically confirmed cases of BM admitted to children's hospital of Tunis were recorded (January 2003 to April 2019). Serogroups of Neisseria meningitidis (Nm) and serotypes of Streptococcus pneumoniae (Sp) and H. influenzae (Hi) and antibiotic resistance were determined using conventional and molecular methods.Among 388 cases, the most frequent species were Sp (51.3%), followed by Nm (27.5%) and Hi (16.8%). We observed a significant decrease in Hi BM rate during the conjugated Hib vaccine use period (P < 0.0001). The main pneumococcal serotypes were 14, 19F, 6B, 23F and 19A and the serotype coverage of PCV10, PCV13, PCV15 and PCV20 was 71.3 and 78.8%, 79.4 and 81.9% respectively. The most frequent Nm serogroup was B (83.1%). Most Hi strains were of serotype b (86.9%). High levels of resistance were found: Sp and Nm to penicillin (respectively 60.1 and 80%) and Hi to ampicillin (42.6%). All meningococcal and Hi isolates were susceptible to third-generation cephalosporins and 7.2% of pneumococcal strains had decreased susceptibility to these antibiotics.The Hib conjugate vaccine decreased the rate of BM. Sp dominated the aetiology of BM in children in Tunisia. Conjugate vaccines introducing decreases not only BM cases but also antimicrobial resistance.

Hib Vaccines: Their Impact on Haemophilus influenzae Type b Disease.

Haemophilus influenzae serotype b (Hib) is an important cause of serious, invasive infections, particularly in young children. Since 1985, a series of vaccines composed of the type b capsular polysaccharide polyribosylribitol phosphate (PRP), followed by PRP conjugated to various proteins, have been licensed for use in the United States and worldwide. The conjugated vaccines offer increased immunogenicity and prolonged durability of immune protection compared to the plain PRP vaccine and increasingly are combined with other childhood vaccines for decreased cost and increased ease of vaccination. Hib vaccines have a very favorable safety profile, have been found to be either cost-saving or cost-effective by many public health agencies, and, in most countries, are initiated during early infancy as part of routine childhood immunization programs. As a result of widespread use of the vaccines, the incidence of Hib infections, and their associated morbidity and mortality, has fallen dramatically across the globe. Yet, many children remain unimmunized or underimmunized against Hib, particularly in limited-resource countries. Future efforts to further reduce the disease burden of Hib infections remain a high priority.

The Challenge of Achieving Immunity Through Multiple-Dose Vaccines in Madagascar.

Administration of many childhood vaccines requires that multiple doses be delivered within a narrow time window to provide adequate protection and reduce disease transmission. Accurately quantifying vaccination coverage is complicated by limited individual-level data and multiple vaccination mechanisms (routine and supplementary vaccination programs). We analyzed 12,541 vaccination cards from 6 districts across Madagascar for children born in 2015 and 2016. For 3 vaccines-pentavalent diphtheria-tetanus-pertussis-hepatitis B-Haemophilus influenzae type b vaccine (DTP-HB-Hib; 3 doses), 10-valent pneumococcal conjugate vaccine (PCV10; 3 doses), and rotavirus vaccine (2 doses)-we used dates of vaccination and birth to estimate coverage at 1 year of age and timeliness of delivery. Vaccination coverage at age 1 year for the first dose was consistently high, with decreases for subsequent doses (DTP-HB-Hib: 91%, 81%, and 72%; PCV10: 82%, 74%, and 64%; rotavirus: 73% and 63%). Coverage levels between urban districts and their rural counterparts did not differ consistently. For each dose of DTP-HB-Hib, the overall percentage of individuals receiving late doses was 29%, 7%, and 6%, respectively; estimates were similar for other vaccines. Supplementary vaccination weeks, held to help children who had missed routine care to catch up, did not appear to increase the likelihood of being vaccinated. Maintaining population-level immunity with multiple-dose vaccines requires a robust stand-alone routine immunization program.

Impact of Haemophilus influenzae type b combination vaccination on asthma symptoms and pneumonia in 5-year-old children in rural Bangladesh: a longitudinal study and comparison with a previous cross-sectional study.

BACKGROUND: Although the prevalence of bronchial asthma has been increasing worldwide since the 1970's, the prevalence among 5-year-old children was significantly lower in 2016 than in 2001 in rural Bangladesh. We aimed to determine whether the Haemophilus influenzae type b (Hib) combination vaccination (without booster) started in 2009 contributed to this decrease. METHODS: A case-control study was conducted among 1658 randomly selected 5-year-old children from Matlab, Bangladesh. Data on wheezing were collected using the International Study of Asthma and Allergies in Childhood questionnaire. The vaccination data were collected from the records of the Matlab Health and Demographic Surveillance System, while data on pneumonia were obtained from the clinical records of Matlab Hospital. Adjusted odds ratios (aORs) were calculated for the risk for wheezing. The reduction rate was calculated to determine the impact of the vaccination on pneumonia history between the present study and our previous study conducted in 2001 by using the following formula: (percentage of pneumonia cases in 2001 - percentage of pneumonia cases in 2016)/(percentage of pneumonia cases in 2001) times 100 (%). RESULTS: Hib combination vaccination was a protecting factor against wheezing (aOR: 0.50; p = 0.010), while pneumonia at 1, 2, 3-4 years of age were risk factors for wheezing (aOR: 2.86, 3.19, 2.86; p = 0.046, 0.030, 0.030, respectively). The history of pneumonia was significantly lower in the 2016 study participants than those in 2001 both in the overall cohort and the wheezing group (paired t-test: p = 0.012, p < 0.001, respectively). Whereas the history of pneumonia decreased when the children grew older in the 2001 overall cohort, it peaked at the age of 2 years in 2016 wheezing group. The reduction rate decreased when children grew older in both the overall cohort and the wheezing group, however, it decreased faster in the wheezing group. CONCLUSIONS: Hib combination vaccination was a protective factor against wheezing in 0-year-old children. However, the effects of vaccination might have attenuated at the ages of 1-4 years, because no booster dose was administered. The addition of a booster dose might further decrease the prevalence of asthma and wheezing.

Haemophilus influenzae type b (Hib) seroprevalence in France: impact of vaccination schedules.

BACKGROUND: Haemophilus influenzae serotype b (Hib) conjugate vaccine was introduced in France in 1992 as a 3 + 1 scheme at 2, 3, and 4 months (primary vaccination) with a booster at the age of 16-18 months. The vaccination was simplified in 2013 to a 2 + 1 scheme at 2 and 4 months (primary immunization) and a booster at the age of 11 months. The coverage was 95.4% in France at 24 months in 2017. During the period 2017-2019 the number of Hib invasive infections increased with several cases of vaccine failure. METHODS: The numbers and proportions of Hib invasive isolates during the period 2017-2019 were compared and vaccine failure cases were explored. A seroprevalence study was performed by measuring anti-polyribosyl-ribitol phosphate (PRP) IgG concentrations by ELISA among children < 5 years of age at the time of sampling covering the periods of the 3 + 1 or 2 + 1 schemes of Hib vaccination. A collection of residual 232 sera was tested (group 3 + 1 n = 130) and (group 2 + 1, n = 102) was used. RESULTS: Anti-PRP IgG concentrations were significantly higher in toddlers of 2 years (median 2.9 µg/ml) in the 3 + 1 group while these concentrations showed a median of 0.58 µg/ml among children in 2 + 1 group. The proportion of children of 2 years of age who achieved 1 µg/ml threshold (56%) was higher in the 3 + 1 group than that observed in the 2 + 1 group (25%). All the detected cases of vaccine failure received the 2 + 1 scheme and anti-PRP IgG levels were less than 1 µg/ml at the admission. However, these levels increased significantly 1 month after the admission suggesting a secondary immune response to the Hib infection. CONCLUSIONS: The simplification of the vaccination to a 2 + 1 scheme seems to reduce the level of anti PRP IgG. Hib antibodies wane rapidly after the 11 months booster and may not be enough to ensure long term protection. Surveillance of cases and monitoring of titres need to be continued to inform future vaccination policy.

Immunogenicity and safety of a quadrivalent meningococcal tetanus toxoid-conjugate vaccine administered concomitantly with other paediatric vaccines in toddlers: a phase III randomised study.

Invasive meningococcal disease has high morbidity and mortality, with infants and young children among those at greatest risk. This phase III, open-label, randomised study in toddlers aged 12-23 months evaluated the immunogenicity and safety of meningococcal tetanus toxoid-conjugate vaccine (MenACYW-TT), a tetanus toxoid conjugated vaccine against meningococcal serogroups A, C, W and Y, when coadministered with paediatric vaccines (measles, mumps and rubella [MMR]; varicella [V]; 6-in-1 combination vaccine against diphtheria, tetanus, pertussis, polio, hepatitis B and Haemophilus influenzae type b [DTaP-IPV-HepB-Hib] and pneumococcal conjugate vaccine [PCV13])(NCT03205371). Immunogenicity to each meningococcal serogroup was assessed by serum bactericidal antibody assay using human complement (hSBA). Vaccine safety profiles were described up to 30 days post-vaccination. A total of 1183 participants were enrolled. The proportion with seroprotection (hSBA ≥1:8) to each meningococcal serogroup at Day 30 was comparable between the MenACYW-TT and MenACYW-TT + MMR + V groups (≥92 and ≥96%, respectively), between the MenACYW-TT and MenACYW-TT + DTaP-IPV-HepB-Hib groups (≥90% for both) and between the MenACYW-TT and MenACYW-TT + PCV13 groups (≥91 and ≥84%, respectively). The safety profiles of MenACYW-TT, and MMR + V, DTaP-IPV-HepB-Hib, and PCV13, with or without MenACYW-TT, were generally comparable. Coadministration of MenACYW-TT with paediatric vaccines in toddlers had no clinically relevant effect on the immunogenicity and safety of any of the vaccines.

Measuring the cellular memory B cell response after vaccination in patients after allogeneic stem cell transplantation.

After allogeneic hematopoietic stem cell transplantation (HSCT), patients are repetitively vaccinated to reduce the risk of infection caused by the immune deficiency following allogeneic HSCT. By the vaccination of transplanted patients, the humoral memory function can be restored in the majority of cases. It is unknown, however, to what extent memory B cells derived from the donor contribute to the mobilization of antibody-secreting cells and long-term humoral memory in patients after allogeneic HSCT. We therefore analyzed patients after allogeneic HSCT for memory B cell responses 7 days after single vaccination against tetanus toxoid (TT), diphtheria toxoid (DT), pertussis toxoid (PT), Haemophilus influenzae type b (Hib), and poliovirus. Patients showed an insufficient mobilization of plasmablasts (PB) after vaccination, whereas healthy subjects (HD, n = 13) exhibited a significant increase of PB in the peripheral blood. Regarding vaccine-specific antibody-secreting PB, all HD responded against all vaccine antigens, as expected. However, only 65% of the patients responded with a measurable increase in IgG-secreting PB against TT, 65% against DT, 33% against PT, and 53% against poliovirus. Correspondingly, the antibody titers on day 7 after vaccination did not increase in patients. A significant increase of serum titers for the vaccine antigens was detectable in the majority of patients only after repetitive vaccinations. In contrast to the low mobilization of vaccine-specific PB after vaccination, a high number of PB before vaccination was detectable in patients following allogeneic HSCT. High frequencies of circulating PB correlated with the incidence of moderate/severe chronic GVHD. In summary, patients showed a weak mobilization of antigen-specific PB and an inadequate increase in antibody titers 7 days after the first vaccination. Patients with moderate or severe chronic GVHD in their history had a significantly higher percentage of IgG-secreting PB prior to vaccination. The antigen specificity of these IgG-secreting PB is currently unknown.

Licensure of a Diphtheria and Tetanus Toxoids and Acellular Pertussis, Inactivated Poliovirus, Haemophilus influenzae Type b Conjugate, and Hepatitis B Vaccine, and Guidance for Use in Infants.

On December 21, 2018 the Food and Drug Administration (FDA) licensed a hexavalent combined diphtheria and tetanus toxoids and acellular pertussis (DTaP) adsorbed, inactivated poliovirus (IPV), Haemophilus influenzae type b (Hib) conjugate (meningococcal protein conjugate) and hepatitis B (HepB) (recombinant) vaccine, DTaP-IPV-Hib-HepB (Vaxelis; MCM Vaccine Company),* for use as a 3-dose series in infants at ages 2, 4, and 6 months (1). On June 26, 2019, after reviewing data on safety and immunogenicity, the Advisory Committee on Immunization Practices (ACIP)† voted to include DTaP-IPV-Hib-HepB in the federal Vaccines for Children (VFC) program.§ This report summarizes the indications for DTaP-IPV-Hib-HepB and provides guidance for its use.

Epidemiology of Haemophilus influenzae in the Republic of Ireland, 2010-2018.

The purpose of this study was to investigate H. influenzae epidemiology in the Republic of Ireland. We performed serotyping, multi-locus sequence typing (MLST) and susceptibility testing on H. influenzae isolates received by the Irish Meningitis and Sepsis Reference Laboratory from 2010 to 2018. Three hundred sixty-seven invasive and 41 non-invasive infection (NII) isolates were received. Invasive isolates were mostly recovered from paediatric (21%) and elderly (42%) populations. Invasive disease was more prevalent in females of childbearing age (72%) compared with males the same age (28%). Non-typeable H. influenzae (NTHi) predominated among invasive (83%) and NII (95%). Invasive Hib disease isolates were infrequent (4%, n = 15). Among invasive disease, Hif was the commonest encapsulated serotype (10%, n = 37), and the only encapsulated serotype detected in NII (5%, 2/41). The first PCR-confirmed serotypes d and a in Ireland were characterised among invasive disease in 2017 and 2018, respectively. MLST revealed a diverse NTHi population, while encapsulated serotypes were clonal. Sequence type (ST) 103 (n = 14) occurred exclusively in invasive NTHi disease. Ampicillin resistance (AmpR) was 18% among invasive isolates and 22% in NII. ß-Lactamase production was the main source of ampicillin resistance in invasive and NII isolates. We detected ß-lactamase negative ampicillin resistance (BLNAR) among invasive isolates. We report an NTHi fluoroquinolone-resistant clone: ST1524 among invasive (n = 2) and NII isolates (n = 2). The Hib vaccine has positively impacted on Hib disease in Ireland, given the low frequency of Hib. The dominance of NTHi, emergence of serotypes a and d and BLNAR suggest a changing H. influenzae epidemiology in Ireland.

Association between season of vaccination and antibody levels against infectious diseases.

Vaccination has reduced the disease burden of vaccine-preventable diseases. However, the extent to which seasonal cycles of immunity could influence vaccine-induced immunity is not well understood. A national cross-sectional serosurveillance study performed in the Netherlands (Pienter-2) yielded data to investigate whether season of vaccination was associated with antibody responses induced by DT-IPV (diphtheria, tetanus and poliomyelitis), MMR (measles, mumps and rubella) and meningococcus C (MenC) vaccines in children. In total, 434 children met the inclusion criteria to study DT-IPV immunity, 811 for MMR and 311 for MenC. Differences in log(antibody levels) by season of vaccination were investigated with linear multivariable regression analyses. Seroconversion rates varied according to season of vaccination for rubella (90% of autumn-vaccinated children vs. 99% of winter-vaccinated had concentrations above cut-off levels). Summer-vaccinated boys showed a slower decline of tetanus antibodies (6% per month), in comparison with winter-vaccinated boys. In conclusion, season of vaccination showed little association with immunological protection. However, a number of associations were seen with a P-value of about 0.03; and adding data from a just-completed nationwide serological study might add more power to the current study. Further immunological and longitudinal investigations could help understand the mechanisms of seasonal influence in vaccine-induced responses.

The influence of maternal mental illness on vaccination uptake in children: a UK population-based cohort study.

Reduced vaccination uptake is a growing and global public health concern. There is limited knowledge about the effect of maternal mental illness (MMI) on rates of childhood vaccination. This retrospective cohort study examined 479,949 mother-baby pairs born between 1993 and 2015 in the Clinical Practice Research Datalink (CPRD GOLD), a UK-based, primary health-care database. The influence of MMI on children's vaccination status at two and five years of age was investigated using logistic regression adjusting for sex of the child, child ethnicity, delivery year, maternal age, practice level deprivation quintile and region. The vaccinations were: 5-in-1 (DTaP/IPV/Hib) and first dose MMR by the age of two; and all three doses of 5-in-1, first and second dose of MMR vaccines by the age of five. Exposure to MMI was defined using recorded clinical events for: depression, anxiety, psychosis, eating disorder, personality disorder and alcohol and substance misuse disorders. The likelihood that a child completed their recommended vaccinations by the age of two and five was significantly lower among children with MMI compared to children with mothers without mental illness [adjusted odds ratio (aOR) 0.86, 95% CI 0.84-0.88, p < 0.001]. The strongest effect was observed for children exposed to maternal alcohol or substance misuse (at two years aOR 0.50, 95% CI 0.44-0.58, p < 0.001). In the UK, an estimated five thousand more children per year would be vaccinated if children with MMI had the same vaccination rates as children with well mothers. Maternal mental illness is a hitherto largely unrecognised reason that children may be missing vital vaccinations at two and five years of age. This risk is highest for those children living with maternal alcohol or substance misuse.

Internal exposure to perfluoroalkyl substances (PFASs) and biological markers in 101 healthy 1-year-old children: associations between levels of perfluorooctanoic acid (PFOA) and vaccine response.

Perfluoroalkyl substances (PFASs) are a complex group of man-made chemicals with high stability and mobility leading to ubiquitous environmental contamination and accumulation in the food chain. In human serum/plasma samples, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are the lead compounds. They are immunotoxic in experimental animals, and epidemiological studies provided evidence of a diminished production of vaccine antibodies in young children. However, information on children of the first year of age is missing but relevant, as they have a relatively high exposure if breastfed, and may have a higher susceptibility as their immune system is developing. In a cross-sectional study with 101 healthy 1-year-old children, internal levels of persistent organic pollutants and a broad panel of biological parameters were investigated at the end of the 1990s. Additional analysis of PFASs resulted in plasma levels (mean ± SD) of PFOA and PFOS of 3.8 ± 1.1 and 6.8 ± 3.4 µg/L, respectively, in the 21 formula-fed children, and of 16.8 ± 6.6 and 15.2 ± 6.9 µg/L in the 80 children exclusively breastfed for at least 4 months. The study revealed significant associations between levels of PFOA, but not of PFOS, and adjusted levels of vaccine antibodies against Haemophilus influenza type b (Hib, r = 0.32), tetanus (r = 0.25) and diphtheria (r = 0.23), with no observed adverse effect concentrations (NOAECs) determined by fitting a 'knee' function of 12.2, 16.9 and 16.2 µg/L, respectively. The effect size (means for PFOA quintiles Q1 vs. Q5) was quantified to be - 86, - 54 and - 53%, respectively. Furthermore, levels of PFOA were inversely associated with the interferon gamma (IFNÉ£) production of ex-vivo lymphocytes after stimulation with tetanus and diphtheria toxoid, with an effect size of - 64 and - 59% (means Q1 vs. Q5), respectively. The study revealed no influence of PFOA and PFOS on infections during the first year of life and on levels of cholesterol. Our results confirmed the negative associations of PFAS levels and parameters of immune response observed in other epidemiological studies, with high consistency as well as comparable NOAECs and effects sizes for the three vaccine antibodies investigated, but for PFOA only. Due to reduction of background levels of PFASs during the last 20 years, children in Germany nowadays breastfed for a long duration are for the most part not expected to reach PFOA levels at the end of the breastfeeding period above the NOAECs determined.

Immunogenicity and safety of a DTaP-IPV/Hib pentavalent vaccine given as primary and booster vaccinations in healthy infants and toddlers in Japan.

BACKGROUND: Globally, the use of single DTaP-IPV/Hib vaccines that combine DTaP-IPV and Hib is widespread, but in Japan vaccination is usually concomitant at separate sites. The immunogenicity and safety of a primary vaccination series and booster of a combined pentavalent DTaP-IPV/Hib vaccine were evaluated and compared to separate administration of DTaP-IPV and Hib in Japanese infants. METHODS: Healthy Japanese infants were administered DTaP-IPV/Hib (Group A: N = 207) or DTaP-IPV + Hib (Group B: N = 207) by the subcutaneous (SC) or DTaP-IPV/Hib by the intramuscular (IM) route (Group C: N = 10). All subjects received a 3-dose primary vaccination series and a booster. Non-inferiority (Group A versus Group B) was tested post-primary series and subsequent post hoc analyses were performed for anti-Hib. Safety was assessed by parental reports. RESULTS: Non-inferiority for SC administration of Group A versus Group B for the primary series was demonstrated for antibody responses to all antigens except Hib using the threshold of 1.0 µg/mL. Post hoc analyses for anti-Hib demonstrated non-inferiority for the primary series response using 0.15 µg/mL, and for pre-booster antibody persistence and the booster response using 0.15 µg/mL and 1.0 µg/mL. The immune response was similar for each antigen following SC or IM administration. There were no safety concerns in any group, and a lower incidence of injection sites for the IM route was observed as expected. CONCLUSIONS: These data show the good immunogenicity and safety profile of the DTaP-IPV/Hib vaccine as a 3-dose infant primary series followed by a booster in the second year of life in Japan.

Comparability studies of hemin from two different origins porcine and bovine in the production of Haemophilus influenzae type b (Hib) polysaccharide.

Hemin is one of the critical components of medium required for growth of Haemophilus influenzae type b (Hib) organisms. It is important to have different sources of critical components to ensure continuous supply for commercial production. Regulatory bodies also recommend having multiple sources for critical components. Hemin is produced from animal blood and the main sources are porcine and bovine origin. The approved Hib vaccine of SIIPL used for immunization is produced using hemin obtained from porcine origin. The present work focuses on the comparison of the growth of organisms on a large scale using hemin from bovine or porcine origin. Purified polysaccharide obtained using bovine source is tested with respect to the set WHO specifications as recommended by regulatory bodies and compared with commercial lots of PRP obtained from using hemin of porcine source. Identical product profile and quality attributes were obtained for PRP produced using bovine hemin and the regular commercial product suggests that there is no change in the product. Hemin from bovine source can be used as a replacement for hemin from porcine source in the fermentation medium for country specific requirement of Hib conjugate vaccine as long as it meets the guidelines on TSE/BSE risk.

Valuing the cost of improving Chilean primary vaccination: a cost minimization analysis of a hexavalent vaccine.

BACKGROUND: The phased withdrawal of oral polio vaccine (OPV) and the introduction of inactivated poliovirus vaccine (IPV) is central to the polio 'end-game' strategy. METHODS: We analyzed the cost implications in Chile of a switch from the vaccination scheme consisting of a pentavalent vaccine with whole-cell pertussis component (wP) plus IPV/OPV vaccines to a scheme with a hexavalent vaccine with acellular pertussis component (aP) and IPV (Hexaxim®) from a societal perspective. Cost data were collected from a variety of sources including national estimates and previous vaccine studies. All costs were expressed in 2017 prices (US$ 1.00 = $Ch 666.26). RESULTS: The overall costs associated with the vaccination scheme (4 doses of pentavalent vaccine plus 1 dose IPV and 3 doses OPV) from a societal perspective was estimated to be US$ 12.70 million, of which US$ 8.84 million were associated with the management of adverse events related to wP. In comparison, the cost associated with the 4-dose scheme with a hexavalent vaccine (based upon the PAHO reference price) was US$ 19.76 million. The cost of switching to the hexavalent vaccine would be an additional US$ 6.45 million. Overall, depending on the scenario, the costs of switching to the hexavalent scheme would range from an additional US$ 2.62 million to US$ 6.45 million compared with the current vaccination scheme. CONCLUSIONS: The switch to the hexavalent vaccine schedule in Chile would lead to additional acquisition costs, which would be partially offset by improved logistics, and a reduction in adverse events associated with the current vaccines.

A Class I Haemophilus ducreyi Strain Containing a Class II hgbA Allele Is Partially Attenuated in Humans: Implications for HgbA Vaccine Efficacy Trials.

Haemophilus ducreyi causes chancroid and is a major cause of cutaneous ulcers in children. Due to environmental reservoirs, both class I and class II H. ducreyi strains persist in cutaneous ulcer regions of endemicity following mass drug administration of azithromycin, suggesting the need for a vaccine. The hemoglobin receptor (HgbA) is a leading vaccine candidate, but its efficacy in animal models is class specific. Controlled human infection models can be used to evaluate vaccines, but only a class I strain (35000HP) has been characterized in this model. As a prelude to evaluating HgbA vaccines in the human model, we tested here whether a derivative of 35000HP containing a class II hgbA allele (FX548) is as virulent as 35000HP in humans. In eight volunteers infected at three sites with each strain, the papule formation rate was 95.8% for 35000HP versus 62.5% for FX548 (P = 0.021). Excluding doses of FX548 that were ≥2-fold higher than those of 35000HP, the pustule formation rate was 25% for 35000HP versus 11.7% for FX548 (P = 0.0053). By Western blot analysis, FX548 and 35000HP expressed equivalent amounts of HgbA in whole-cell lysates and outer membranes. The growth of FX548 and 35000HP was similar in media containing hemoglobin or hemin. By whole-genome sequencing and single-nucleotide polymorphism analysis, FX548 contained no mutations in open reading frames other than hgbA We conclude that by an unknown mechanism, FX548 is partially attenuated in humans and is not a suitable strain for HgbA vaccine efficacy trials in the model.

Seroprotection at Different Levels of the Healthcare System After Routine Vaccination With Diphtheria-Tetanus-Pertussis whole cell-Hepatitis B-Haemophilus influenzae Type B in Lao People's Democratic Republic.

BACKGROUND: The Lao People's Democratic Republic continues to sustain a considerable burden of vaccine-preventable diseases because of incomplete vaccine coverage and weak vaccine responses. We have assessed seroconversion after routine vaccination with the pentavalent vaccine to capture weaknesses of vaccine management at the different levels of the healthcare system. METHODS: A total of 1151 children (aged 8-28 months) with 3 documented doses of the pentavalent vaccine delivered at central hospitals in Vientiane and the provincial hospital, 3 district hospitals, and 10 health centers in Bolikhamxay province were enrolled. Sociodemographic information was collected with a standardized questionnaire. Serum samples were analyzed for antibodies against vaccine components, and bivariate and multivariable analyses were performed to identify risk factors for low vaccine responses. RESULTS: Seroprotection rates at the provincial, district, and health center level were as high as in central hospitals, but seroprotection rates in areas covered by remote health centers were significantly lower. Protective levels also rapidly decreased with age at sampling. Seroprotection rates in Bolikhamxay against the different components reached 70%-77% and were up to 20% higher than in previous studies in the same region; 18.8% more children received the hepatitis B vaccine birth dose and the hepatitis B virus infection rate was 4 times lower. CONCLUSIONS: Vaccine immunogenicity has dramatically improved in a central province, likely due to training and investment in the cold chain. Nevertheless, there remains a need to focus on the "last mile" in remote areas were most children are vaccinated through outreach activities.

Continuing surveillance of invasive Haemophilus influenzae disease in northwestern Ontario emphasizes the importance of serotype a and non-typeable strains as causes of serious disease: a Canadian Immunization Research Network (CIRN) Study.

In the post-Haemophilus influenzae serotype b (Hib) vaccine era, invasive H. influenzae serotype a (Hia) disease emerged in Canadian First Nation, Inuit, and Alaskan Indigenous populations. Previous studies by our group found a high incidence of invasive Hia disease in northwestern Ontario. We retrospectively reviewed 24 cases (4 pediatric and 20 adult) of invasive H. influenzae disease hospitalized at the northwestern Ontario regional hospital between August 2011 and June 2018. The objectives were to further document the changing epidemiology of invasive H. influenzae disease in the region and to discuss potential control measures. Twenty-two H. influenzae isolates were serotyped and characterized using molecular-biological methods. Of the serotyped cases, there were 2 Hib, 9 Hia, and 11 non-typeable (NTHi). All Hia isolates belonged to the most common sequence types (ST) found in Canada (ST-23 and ST-929); 8 out of 9 were pan susceptible to antibiotics. One (11%) of 9 Hia and 5 (45%) of 11 NTHi cases were fatal. Our data on the consistent presence of serious invasive H. influenzae disease, with 41% prevalence of Hia (9 out of 22 serotyped isolates) and 50% prevalence of NTHi strains (11 out of 22), emphasize the importance of continued surveillance of H. influenzae in the post-Hib vaccine era and are critical information to inform potential vaccine development.