Progress in vaccination against Haemophilus influenzae type b in the Americas.
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ABSTRACT:
SUBMITTER: Danovaro-Holliday MC
PROVIDER: S-EPMC2292748 | biostudies-literature | 2008 Apr
REPOSITORIES: biostudies-literature
Publications
Progress in vaccination against Haemophilus influenzae type b in the Americas.
Danovaro-Holliday M Carolina MC Garcia Salvador S de Quadros Ciro C Tambini Gina G Andrus Jon K JK
PLoS medicine 20080401 4
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Project description:Current study aimed to estimate clinical and economic outcomes of providing the Haemophilus influenzae type b (Hib) vaccination as a national vaccine immunization program in Thailand. A decision tree combined with Markov model was developed to simulate relevant costs and health outcomes covering lifetime horizon in societal and health care payer perspectives. This analysis considered children aged under 5 years old whom preventive vaccine of Hib infection are indicated. Two combined Hib vaccination schedules were considered: three-dose series (3 + 0) and three-dose series plus a booster does (3 + 1) compared with no vaccination. Budget impact analysis was also performed under Thai government perspective. The outcomes were reported as Hib-infected cases averted and incremental cost-effectiveness ratios (ICERs) in 2014 Thai baht (THB) ($) per quality-adjusted life year (QALY) gained. In base-case scenario, the model estimates that 3,960 infected cases, 59 disability cases, and 97 deaths can be prevented by national Hib vaccination program. The ICER for 3 + 0 schedule was THB 1,099 ($34) per QALY gained under societal perspective. The model was sensitive to pneumonia incidence among aged under 5 years old and direct non-medical care cost per episode of Hib pneumonia. Hib vaccination is very cost-effective in the Thai context. The budget impact analysis showed that Thai government needed to invest an additional budget of 110 ($3.4) million to implement Hib vaccination program. Policy makers should consider our findings for adopting this vaccine into national immunization program.
| S-EPMC5701919 | biostudies-literature
Project description:We assessed the impact of Haemophilus influenzae type b (Hib) vaccination, introduced in France in early 1993, on the incidence of invasive Haemophilus influenzae (Hi) disease up to 2008.The incidence of Hi meningitis fell from 0·9/100000 in 1991–1992 to 0·09/100 000 in 1996–2008,with a marked decline (96%) in children aged <5 years, including infants aged <3 months, from 12 to 0·4 /100 000. The incidence of invasive Hi disease also decreased in children aged <15 years from 6 to 0·7 /100 000, remained stable in the 15–64 years age group at about 0·5/100 000,and increased slightly from 2·0 to 2·4 /100 000 in persons aged >64 years. No emergence of non-encapsulated or encapsulated non-vaccine serotypes was observed. These findings confirm the major direct impact of Hib vaccination on the incidence of Hi invasive disease in children and the indirect benefit of vaccination for infants too young to be vaccinated.
| S-EPMC9155286 | biostudies-literature
Project description:BackgroundGlobally, vaccine-preventable diseases remain a significant cause of early childhood mortality despite concerted efforts to improve vaccine coverage. One reason for impaired protection may be the influence of prenatal exposure to parasitic antigens on the developing immune system. Prior research had shown a decrease in infant vaccine response after in utero parasite exposure among a maternal cohort without aggressive preventive treatment. This study investigated the effect of maternal parasitic infections on infant vaccination in a more recent setting of active anti-parasitic therapy.Methodology/principal findingsFrom 2013-2015, 576 Kenyan women were tested in pregnancy for malaria, soil-transmitted helminths, filaria, and S. haematobium, with both acute and prophylactic antiparasitic therapies given. After birth, 567 infants received 10-valent S. pneumoniae conjugate vaccine and pentavalent vaccine for hepatitis B, pertussis, tetanus, H. influenzae type B (Hib) and C. diphtheriae toxoid (Dp-t) at 6, 10, and 14 weeks. Infant serum samples from birth, 10 and 14 weeks, and every six months until age three years, were analyzed using a multiplex bead assay to quantify IgG for Hib, Dp-t, and the ten pneumococcal serotypes. Antenatal parasitic prevalence was high; 461 women (80%) had at least one and 252 (43.6%) had two or more infections during their pregnancy, with the most common being malaria (44.6%), S. haematobium (43.9%), and hookworm (29.2%). Mixed models comparing influence of infection on antibody concentration revealed no effect of prenatal infection status for most vaccine outcomes. Prevalences of protective antibody concentrations after vaccination were similar among the prenatal exposure groups.Conclusions/significanceThese findings are in contrast with results from our prior cohort study performed when preventive anti-parasite treatment was less frequently given. The results suggest that the treatment of maternal infections in pregnancy may be able to moderate the previously observed effect of antenatal maternal infections on infant vaccine responses.
| S-EPMC6413956 | biostudies-literature
Project description:BackgroundChina is the only country in the world that has not included the Haemophilus influenzae type b (Hib) vaccine in its National Immunization Program, making it more difficult to eliminate Hib-related diseases through Hib vaccination. It is necessary to study parental preferences for Hib vaccination to optimize vaccine promotion strategies in China.ObjectiveThis study aimed to investigate Chinese parental preference for five attributes of Hib vaccination, i.e., the place of origin, effectiveness, adverse event, doctors' recommendation, and the price of full vaccination when making a decision to vaccinate their children under 2 years old.MethodsA cross-sectional survey was conducted in two cities in Zhejiang Province from November to December in 2020 using a discrete choice experiment (DCE). A mixed logit model was used to estimate participating parents' preference for Hib vaccination attributes included in the DCE. Subgroup analysis and probability analysis were also conducted to capture the heterogeneity and trade-off of parental preference for Hib vaccination.ResultsData from 6,168 observations were included in the analyses. Parents of children are, on average, more likely to voice a positive preference for Hib vaccination. Such attributes of Hib vaccination as effectiveness and doctor's recommendation have a significant positive influence on parents' preference for Hib vaccination, while imported vaccines, adverse events, and the price of full vaccination have a significant negative influence on parents' preference. Parents with different demographic characteristics also existed heterogeneities in preference for Hib vaccination. Parents will make a trade-off on price if the Hib vaccine has a good performance on effectiveness and safety.ConclusionThe study found that, regardless of the place of origin of the Hib vaccine, parents with children under 2 years old prefer to compromise on price if the vaccine has a better effectiveness and safety profile. A proactive recommendation from doctors would strengthen their willingness for Hib vaccination. These findings help aid the development of communication strategies with parents for Hib vaccination in China.
| S-EPMC9710483 | biostudies-literature
Project description:Transcriptome analysis of NTHi 86-028NPrpsL, NTHi 86-028NPrpsL∆fur, and NTHi 86-028NPrpsL∆fur(pT-fur) strains Nontypeable Haemophilus influenzae (NTHi) is a commensal microorganism of the normal human nasopharyngeal flora, yet also an opportunistic pathogen of the upper and lower respiratory tracts. Changes in gene expression patterns in response to host microenvironments are likely critical for survival. One such system of gene regulation is the ability to carefully regulate iron uptake. A central regulatory system that controls iron uptake, mediated by the ferric uptake regulator Fur, is present in multiple bacteria, including NTHi. To understand the regulation of iron homeostasis in NTHi, fur was deleted in the NTHi strain 86-028NPrpsL. Using RNA-Seq, we identified both protein-encoding and small RNA genes whose expression was repressed or activated by Fur. Overall design: These data comprise transcriptional anaylses of an rpsL mutant of 86-028NP, an isogenic fur mutant of 86-028NPrpsL and a complemented fur mutant strain. All strains were grown in defined medium containing 10 µg/ml human hemoglobin to mid-log phase. Cells were then harvested and RNA extracted. A total of three biological replicates were generated for these analyses.
2015-07-01 | GSE58890 | GEO
Project description:A real-time PCR assay targeting the capsulation locus of Haemophilus influenzae type b (Hib) was developed. The linear detection range was from 1 to 10(6) microorganisms per reaction mixture. No H. influenzae other than Hib or any other control bacteria typically found in the upper respiratory tract was detected.
| S-EPMC497579 | biostudies-literature
Project description:Meningitis caused by Haemophilus influenzae type b (Hib) was eliminated in Oman after the introduction of Hib vaccine in 2001. However, a case of H. influenzae type a meningitis was diagnosed in a child from Oman in 2015, which highlights the need to monitor the incidence of invasive non-Hib H. influenzae disease.
| S-EPMC5512487 | biostudies-literature
Project description: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.
| S-EPMC8482018 | biostudies-literature
Project description:Severe infections caused by Haemophilus influenzae type a (Hia) have reached alarming rates in some Canadian Aboriginal communities. We sought to estimate the frequency of exposure to this pathogen and timelines for boosting protective antibodies. We developed a model of secondary antigenic challenge (natural exposure), and used data for anti-Hia antibodies in serum samples of healthy and immunocompromised adults in a population of Northwestern Ontario, Canada. We parameterized the model with available estimates from previous studies for the decay rate of antibody and its protective levels against both Hia carriage and invasive disease. Simulations were initialized using antibody concentrations from data. We investigated both the duration of immunity without secondary antigenic challenge and the average time between subsequent exposures to Hia. When there was no new natural exposure, serum antibody concentrations in healthy Aboriginal individuals decreased below the level (1 μg/ml) assumed for protection against invasive Hia disease 3 years after primary exposure. This period was shorter (about 2 years) for Aboriginal individuals suffering from chronic renal failure. We estimated that a new antigenic challenge occurs once in 5 and 2 years for healthy and immunocompromised Aboriginal individuals, respectively. More frequent natural exposure was required to maintain protective antibody levels for non-Aboriginal individuals compared to Aboriginal individuals. The findings suggest that frequent boosting of natural immunity is required to maintain the anti-Hia antibody levels protecting against invasive Hia disease, particularly in individuals with underlying medical conditions. This information has important implications for immunization when an anti-Hia vaccine becomes available.
| S-EPMC4929236 | biostudies-literature
Project description:Non-typeable Haemophilus influenzae (NTHi) causes persistent respiratory infections in patients with chronic obstructive pulmonary disease (COPD), probably linked to its capacity to invade and reside within pneumocytes. In the alveolar fluid, NTHi is in contact with pulmonary surfactant, a lipoprotein complex that protects the lung against alveolar collapse and constitutes the front line of defense against inhaled pathogens and toxins. Decreased levels of surfactant phospholipids have been reported in smokers and patients with COPD. The objective of this study was to investigate the effect of surfactant phospholipids on the host-pathogen interaction between NTHi and pneumocytes. For this purpose, we used two types of surfactant lipid vesicles present in the alveolar fluid: (i) multilamellar vesicles (MLVs, > 1 μm diameter), which constitute the tensioactive material of surfactant, and (ii) small unilamellar vesicles (SUVs, 0.1 μm diameter), which are generated after inspiration/expiration cycles, and are endocytosed by pneumocytes for their degradation and/or recycling. Results indicated that extracellular pulmonary surfactant binds to NTHi, preventing NTHi self-aggregation and inhibiting adhesion of NTHi to pneumocytes and, consequently, inhibiting NTHi invasion. In contrast, endocytosed surfactant lipids, mainly via the scavenger receptor SR-BI, did not affect NTHi adhesion but inhibited NTHi invasion by blocking bacterial uptake in pneumocytes. This blockade was made possible by inhibiting Akt phosphorylation and Rac1 GTPase activation, which are signaling pathways involved in NTHi internalization. Administration of the hydrophobic fraction of lung surfactant in vivo accelerated bacterial clearance in a mouse model of NTHi pulmonary infection, supporting the notion that the lipid component of lung surfactant protects against NTHi infection. These results suggest that alterations in surfactant lipid levels in COPD patients may increase susceptibility to infection by this pathogen.
| S-EPMC6431623 | biostudies-literature