Explore the vast range of titles available.

The ability of pneumococcal conjugate vaccine (PCV) to decrease transmission by blocking the acquisition of colonization has been attributed to herd immunity. We describe the role of mucosal immunoglobulin G (IgG) to capsular polysaccharide (CPS) in mediating protection from carriage, translating our findings from a murine model to humans. We used a flow cytometric assay to quantify antibody-mediated agglutination demonstrating that hyperimmune sera generated against an unencapsulated mutant was poorly agglutinating. Passive immunization with this antiserum was ineffective to block acquisition of colonization compared to agglutinating antisera raised against the encapsulated parent strain. In the human challenge model, samples were collected from PCV and control-vaccinated adults. In PCV-vaccinated subjects, IgG levels to CPS were increased in serum and nasal wash (NW). IgG to the inoculated strain CPS dropped in NW samples after inoculation suggesting its sequestration by colonizing pneumococci. In post-vaccination NW samples pneumococci were heavily agglutinated compared with pre-vaccination samples in subjects protected against carriage. Our results indicate that pneumococcal agglutination mediated by CPS-specific antibodies is a key mechanism of protection against acquisition of carriage. Capsule may be the only vaccine target that can elicit strong agglutinating antibody responses, leading to protection against carriage acquisition and generation of herd immunity.

Haemophilus influenzae type b (Hib) conjugate vaccines have drastically reduced disease incidence worldwide. Protection against Hib infection has relied on the serum bactericidal activity (SBA) of antibodies to the Hib capsular polysaccharide (polyribosylribitol phosphate). However, licensure usually relies on measuring induction of antibodies to PRP as a surrogate for SBA. In a phase III clinical trial we compared a PRP-conjugate vaccine using the nontoxic diphtheria toxin mutant, CRM197, as carrier protein with the licensed tetanus toxoid conjugate when administered subcutaneously as a three dose primary series in Japanese infants. As an addition to the phase III study, we have now evaluated SBA and show PRP-CRM197 induces higher levels of SBA than PRP-T four weeks after the primary series, with a statistically significant correlation with anti-PRP titers. This data confirms the superior immunogenicity of PRP-CRM197 compared with PRP-T assessed as SBA following a three-dose primary series by subcutaneous administration. Clinical trial registry: Registered on ClinicalTrials.gov (NCT01379846).

Background. The RTS,S/AS01E malaria candidate vaccine is being developed for immunization of African infants through the Expanded Program of Immunization (EPI). Methods. This phase 2, randomized, open, controlled trial conducted in Ghana, Tanzania, and Gabon evaluated the safety and immunogenicity of RTS,S/AS01E when coadministered with EPI vaccines. Five hundred eleven infants were randomized to receive RTS,S/AS01E at 0, 1, and 2 months (in 3 doses with diphtheria, tetanus, and wholecell pertussis conjugate [DTPw]; hepatitis B [HepB]; Haemophilus influenzae type b [Hib]; and oral polio vaccine [OPV]), RTS,S/AS01E at 0, 1, and 7 months (2 doses with DTPwHepB/Hib+OPV and 1 dose with measles and yellow fever), or EPI vaccines only. Results. The occurrences of serious adverse events were balanced across groups; none were vaccine-related. One child from the control group died. Mild to moderate fever and diaper dermatitis occurred more frequently in the RTS,S/AS01E coadministration groups. RTS,S/AS01E generated high anti-circumsporozoite protein and anti- hepatitis B surface antigen antibody levels. Regarding EPI vaccine responses upon coadministration when considering both immunization schedules, despite a tendency toward lower geometric mean titers to some EPI antigens, predefined noninferiority criteria were met for all EPI antigens except for polio 3 when EPI vaccines were given with RTS,S/AS01E at 0, 1, and 2 months. However, when antibody levels at screening were taken into account, the rates of response to polio 3 antigens were comparable between groups. Conclusion. RTS,S/AS01E integrated in the EPI showed a favorable safety and immunogenicity evaluation. Trial registration. ClinicalTrials.gov identifier: NCT00436007. GlaxoSmithKline study ID number: 106369 (Malaria-050).

Demographic and health surveys, immunization coverage surveys and administrative data often divergently estimate vaccination coverage, which hinders pinpointing districts where immunization services require strengthening. We assayed vaccination coverage in three regions in Ethiopia by coverage surveys and linked serosurveys. Households with children aged 12-23 (N = 300) or 6-8 months (N = 100) in each of three districts (woredas) were randomly selected for immunization coverage surveys (inspection of vaccination cards and immunization clinic records and maternal recall) and linked serosurveys. IgG-ELISA serologic biomarkers included tetanus antitoxin ≥ 0.15 IU/ml in toddlers (receipt of tetanus toxoid) and Haemophilus influenzae type b (Hib) anti-capsular titers ≥ 1.0 mcg/ml in infants (timely receipt of Hib vaccine). Coverage surveys enrolled 1,181 children across three woredas; 1,023 (87%) also enrolled in linked serosurveys. Administrative data over-estimated coverage compared to surveys, while maternal recall was unreliable. Serologic biomarkers documented a hierarchy among the districts. Biomarker measurement in infants provided insight on timeliness of vaccination not deducible from toddler results. Neither administrative projections, vaccination card or EPI register inspections, nor parental recall, substitute for objective serological biomarker measurement. Including infants in serosurveys informs on vaccination timeliness.

•The study vaccine (Hib-TT) administered according to a 3+1 schedule is immunogenic.•Immune responses to Hib-TT vaccination and to licensed Hib vaccines are comparable.•Hib-TT primary and booster vaccination safety profiles are similar to other Hib vaccines.•Immune response to routine vaccines is not impacted by co-administration with Hib-TT. Vaccination against Haemophilus influenzae type b (Hib) is included in routine pediatric immunization schedule in the United States. Previous vaccine shortages have created the need for additional options for Hib vaccination. This phase III, randomized, multi-centered study (NCT01000974) evaluated the safety and immunogenicity of a monovalent tetanus toxoid-conjugate Hib vaccine (Hib-TT) compared to a monovalent (Hib-TT control) and a combination Hib-TT vaccine. We hierarchically assessed lot-to-lot consistency of 3 Hib-TT lots and non-inferiority of Hib-TT to Hib-TT control. We co-administered routine pediatric vaccines with Hib-TT vaccines at 2, 4, 6months (primary vaccination) and 15–18months of age (booster vaccination). We recorded adverse events (AEs) for 4 (solicited) and 31days (unsolicited) post-vaccination and serious AEs (SAEs) throughout the study. Of 4009 enrolled children, 3086 completed booster phase. Lot-to-lot consistency was not demonstrated. The study met statistical criteria for non-inferiority of Hib-TT to Hib-TT control in terms of immune responses to Hib and co-administered vaccines’ antigens, but not in terms of participants achieving post-primary vaccination anti-PRP levels ≥1µg/mL. Because of the hierarchical nature of the objectives, non-inferiority could not be established. In all groups, 92.5–96.7% and 99.6–100% of participants achieved anti-PRP levels ≥0.15µg/mL, while 78.3–89.8% and 97.9–99.1% had anti-PRP levels ≥1µg/mL, post-primary and post-booster vaccination, respectively. Immune responses to co-administered vaccines and reported incidence of AEs were comparable among groups. We recorded SAEs for 107/2963 (3.6%), 24/520 (4.6%), and 21/520 (4.0%) children post-primary vaccination, and 29/2337 (1.2%), 4/435 (0.9%), and 2/400 (0.5%) children post-booster vaccination with Hib-TT, Hib-TT control and combination Hib-TT vaccine, respectively; 6/5330 (0.1%) SAEs in the Hib-TT groups were considered vaccine-related. Hib-TT induced seroprotective antibody concentrations in the majority of participants and was well-tolerated when co-administered with routine pediatric vaccines according to a 3+1 schedule.

► We studied 164 infants in a RCT who were randomized to prebiotics or placebo added to formula feeding. ► We examined their immunoglobulin-G concentrations specific to Hib and tetanus immunizations. ► Prebiotics supplementation has no effect on vaccination specific antibody levels in young infants. Previous studies have shown, that prebiotics can modulate the immune response in infants at risk for allergy, leading to a lower incidence of atopic dermatitis. Few studies have evaluated the effect of prebiotic carbohydrates alone on the vaccine-specific antibody response as a marker for the development of the immune system in healthy infants not at risk for allergy. This study evaluates the effect of adding a specific prebiotic mixture of short chain galacto-oligosaccharides (scGOS)/long chain fructo-oligosaccharides (lcFOS) ratio 9:1 and pectin-derived acidic oligosaccharides (pAOS) to formula feeding on the specific immunoglobulin responses to Haemophilus influenza type b (Hib) and tetanus immunization in healthy non-atopic infants during the first year of life. This substudy has been embedded in a multinational multicenter RCT (n=1130 children) to evaluate the effect of study prebiotics on the incidence of fever episodes during the first year of life. The study prebiotics were administered throughout the first year of life. This is a substudy on the vaccine-specific immunoglobulin responses to Hib and tetanus immunizations. Only data of the Dutch children, 80 in the prebiotics group and 84 in the control group, were used for this substudy. They all followed the national vaccination schedule leading to a homogeneous group. Blood was sampled at 6 and 12months of age. Hib immunizations: median values did not differ between groups at the age of 6 and 12months. At the age of 12months, 34 out of 37 (91.9%) infants in the prebiotics group and 31 out of 34 infants (91.2%) in the control group had Hib antibody levels >1.0μg/ml. Tetanus immunizations: median values did not differ between groups at the age of 6 and 12months and were above the cut-off value of 0.1IU/ml in all infants in both the prebiotics and the control group. No effect of prebiotics supplementation on vaccination specific antibody levels was found in children up to the age of 12months; the vaccine specific antibody levels in infants fed the study prebiotics or a control diet were similar during the first year of life. We hypothesize that this specific prebiotic mixture, which resembles the composition of oligosaccharides in human milk, mainly promotes Th1 and Treg dependent immune responses and induces a down regulation of IgE-mediated allergic responses, while the desired vaccine-specific serum antibody responses remain intact.

Background WHO recommended incorporation of Haemophilus influenzae type b (Hib) vaccination into immunization program. Indonesia would adopt Hib as a National Immunization Program in 2013. We aimed at analyzing immunogenicity, safety, and consistency of a new combined DTP-HB-Hib (diphtheria-tetanus-pertussis-Hepatitis B-Haemophilus influenza B) vaccine. Methods A prospective, randomized, double blind, multicenter, phase III study of Bio Farma DTP-HB-Hib vaccine conducted in Jakarta and Bandung, August 2012 - January 2013. Subjects were divided into three groups with different batch number. Healthy infants 6–11 weeks of age at enrollment were immunized with 3 doses of DTP-HB-Hib vaccine with interval of 4 weeks, after birth dose of hepatitis B vaccine. Blood samples obtained prior to vaccination and 28 days after the third dose. Safety measures recorded until 28 days after each dose. Results Of 600 subjects, 575 (96 %) completed study protocol. After 3 doses, 100.0 and 96.0 % had anti-PRP concentration ≥0.15 and ≥1.0 μg/ml. Anti-diphtheria and anti-tetanus concentration ≥0.01 IU/ml detected in 99.7 and 100.0 %; while concentration ≥0.1 IU/ml achieved in 84.0 and 97.4 %. Protective anti-HBs found in 99.3 %. The pertussis vaccine response rate was 84.9 %. None Serious Adverse events (SAEs) considered related to study vaccine or procedure. Conclusions The 3-dose of DTP-HB-Hib was immunogenic, well tolerated and suitable for replacement of licensed-equivalent vaccines based on immunologic and safety profiles. Trial registration NCT01986335 – October 30 th 2013.

Background. Infections caused by group B streptococcal (GBS) type V are increasingly common. Capsular polysaccharide (CPS)-protein conjugate GBS vaccines are immunogenic in healthy adults, but type V vaccines have not previously been tested. Methods. Thirty-five healthy, nonpregnant women were randomized to receive an intramuscular dose of GBS type V CPS-tetanus toxoid (TT) vaccine (n=15), GBS type V CPS-cross-reactive material (CRM197) conjugate vaccine (n=15), or placebo (n=5) (double-masked design). Levels of serum antibodies to type V CPS were measured by ELISA, and functional activity was measured by opsonophagocytosis. Results. The vaccines were well tolerated. Significant increases in type V CPS-specific immunoglobulin G (IgG) were elicited by both vaccines, peaking at 4*8 weeks and persisting for 26 weeks. Four-fold or greater increases in type V CPS*specific IgG concentrations were noted in postimmunization serum samples obtained from 93% of subjects in each vaccine group. These concentrations persisted in ⩾85% of conjugate-vaccine recipients 104 weeks later. Type V CPS*specific immunoglobulin M was a dominant isotype of immune response to each conjugate. Postimmunization serum samples promoted opsonophagocytic killing of GBS type V in vitro, whereas those from placebo recipients did not. Conclusion. GBS type V conjugate vaccines are safe and immunogenic and would be appropriate for inclusion in a candidate multivalent GBS vaccine.

BackgroundA quadrivalent meningococcal conjugate vaccine (MCV-4) is recommended for United States teenagers. The duration of protective immunity is unknown. We investigated serum antibody persistence 3 years after vaccination of adolescents MethodsSerum samples from participants of a randomized trial who had received MCV-4 (n=52) or polysaccharide vaccine (MPSV-4; n=48) and from unvaccinated controls (n=60) were assayed for serogroups C, W-135, and Y anticapsular antibody concentrations by use of a radioantigen binding assay and for bactericidal activity (in a human complement assay) and passive protection against serogroup C bacteremia in an infant rat model ResultsA higher proportion of participants in the vaccine groups had protective bactericidal titers (⩾1:4), compared with that in the control group (for MCV-4 recipients vs. controls, P<.01; for MPSV-4 recipients vs. controls, P⩽.06). More MCV-4 recipients had W-135 bactericidal titers ⩾1:4 than did MPSV-4 recipients (P=.01). More MCV-4 recipients had passive protective activity against serogroup C bacteremia than did MPSV-4 recipients (76% vs. 49%; P<.01). The differences in protective activity were largest between participants in the vaccine groups with bactericidal titers <1:4 (63% protective in MCV-4 recipients vs. 31% protective in MPSV-4 recipients; P=.01) ConclusionsCompared with MPSV-4, MCV-4 elicited greater persistence of antibody activity against serogroups C and W-135 at 3 years after vaccination in adolescents. On the basis of passive protection data in an infant rat model, bactericidal titers ⩾1:4 underestimate protective immunity

Active inflammatory bowel disease (IBD) often coincides with increases of Ruminococcus gnavus, a gut microbe found in nearly everyone. It was not known how, or if, this correlation contributed to disease. We investigated clinical isolates of R. gnavus to identify molecular mechanisms that would link R. gnavus to inflammation. Here, we show that only some isolates of R. gnavus produce a capsular polysaccharide that promotes a tolerogenic immune response, whereas isolates lacking functional capsule biosynthetic genes elicit robust proinflammatory responses in vitro. Germ-free mice colonized with an isolate of R. gnavus lacking a capsule show increased measures of gut inflammation compared to those colonized with an encapsulated isolate in vivo. These observations in the context of our earlier identification of an inflammatory cell-wall polysaccharide reveal how some strains of R. gnavus could drive the inflammatory responses that characterize IBD.