<i>Haemophilus influenzae</i> type b and cross-reactive antigens in natural Hib infection dynamics; modelling in two populations

Leino, Tuija; Auranen, Kari; Mäkelä, P. Helena; Käyhty, Helena; Ramsay, Mary; Slack, Mary P. E.; Takala, Aino K.

doi:10.1017/s0950268802007173

Cited by 15 publications

(17 citation statements)

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“…We did not structure the model by age, but we understand that the incidence of Hib could be affected by contact patterns between different age groups, especially among young children [ 6 , 27 , 41 ]. We also note that antigens from several organisms other than Hib can induce cross-reactive antibodies to Hib capsular polysaccharide [ 42 – 44 ], and may therefore boost acquired immunity and increase the protection levels against Hib disease. In our model, we assumed that exposure to infection during partial protection (if infection occurs) leads to carriage, but not to the symptomatic disease.…”

Section: Discussionmentioning

confidence: 99%

Modelling the effects of booster dose vaccination schedules and recommendations for public health immunization programs: the case of Haemophilus influenzae serotype b

Charania

Moghadas

2017

BMC Public Health

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Background Haemophilus influenzae serotype b (Hib) has yet to be eliminated despite the implementation of routine infant immunization programs. There is no consensus regarding the number of primary vaccine doses and an optimal schedule for the booster dose. We sought to evaluate the effect of a booster dose after receiving the primary series on the long-term disease incidence.MethodsA stochastic model of Hib transmission dynamics was constructed to compare the long-term impact of a booster vaccination and different booster schedules after receiving the primary series on the incidence of carriage and symptomatic disease. We parameterized the model with available estimates for the efficacy of Hib conjugate vaccine and durations of both vaccine-induced and naturally acquired immunity.ResultsWe found that administering a booster dose substantially reduced the population burden of Hib disease compared to the scenario of only receiving the primary series. Comparing the schedules, the incidence of carriage for a 2-year delay (on average) in booster vaccination was comparable or lower than that observed for the scenario of booster dose within 1 year after primary series. The temporal reduction of symptomatic disease was similar in the two booster schedules, suggesting no superiority of one schedule over the other in terms of reducing the incidence of symptomatic disease.ConclusionsThe findings underscore the importance of a booster vaccination for continued decline of Hib incidence. When the primary series provides a high level of protection temporarily, delaying the booster dose (still within the average duration of protection conferred by the primary series) may be beneficial to maintain longer-term protection levels and decelerate the decline of herd immunity in the population.Electronic supplementary materialThe online version of this article (10.1186/s12889-017-4714-9) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Modelling the effects of booster dose vaccination schedules and recommendations for public health immunization programs: the case of Haemophilus influenzae serotype b

Charania

Moghadas

2017

BMC Public Health

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“…The specificity of the assay is stressed by the finding of a considerable proportion of unimmunized adults with low unprotective anti-Hib antibody concentrations. The low but presumably protective titers found in the unimmunized infants might be explained by persisting maternal antibodies on the one hand and emerging cross-reactive protective antibodies on the other hand (19). In contrast to the native Hib polysaccharide, a protein-conjugated Hib vaccine behaves physiologically like proteins such as tetanus toxoid (29) and confers an effective protection against Hib to infants.…”

Section: Discussionmentioning

confidence: 99%

Levels of Antibodies Specific to Tetanus Toxoid,Haemophilus influenzaeType b, and Pneumococcal Capsular Polysaccharide in Healthy Children and Adults

Schauer

Stemberg

Rieger

et al. 2003

Clin Vaccine Immunol

114

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Antibody levels specific for capsular polysaccharides of Streptococcus pneumoniae and Haemophilus influenzae type b (Hib) and for tetanus toxoid were measured in serum samples of 386 age-stratified subjects. The study group consists of healthy adult blood donors and hospitalized children undergoing elective surgery, excluding individuals with a history of infection. In children, anti-tetanus toxoid antibody levels displayed two peaks of 1.20 IU/ml (20.4 mg/liter) and 1.65 IU/ml (28.1 mg/liter) related to the schedule of routine childhood immunization in the first year and at 8 years of age. Eighty percent of the antibodies are of the immunoglobulin G1 (IgG1) isotype. For pneumococcal capsular polysaccharide (PCP), the specific antibody levels represent the acquisition of natural immunity. The initial concentration of 9.2 mg/liter was low in infancy (0.5 to 1 years of age) and remained low until 3 to 4 years of age (14.6 mg/liter). During this period PCP antibodies were almost 100% of the IgG2 subclass. Thereafter, IgG anti-PCP antibody titers increased steadily to adult levels (59.5 mg/liter). The data are intended to provide reference ranges to aid in the interpretation of specific antibody determinations in the clinical setting.Serum-specific antibody levels are widely used as indicators of immune competence (25,31). Interpretation of the results may be difficult. Although patients with congenital immunodeficiencies, such as common variable immunodeficiency (1, 7), selective immunoglobulin G (IgG) subclass deficiency (2, 8), and selective antibody deficiency with normal immunoglobulins (2), often have low levels of serum antibodies, many subjects with normal immune function also have low levels of serum-specific antibodies. A physiological delay of the immune response, especially to polysaccharide capsular antigens, a lack of immunization and, in addition, a decrease in specific antibody titers with time (11, 18) determine the outcome of serumspecific antibody measurements. Furthermore, in recent years the routine vaccination schedule has changed. In particular, Haemophilus influenzae type b (Hib) conjugate was introduced (36). Moreover, routine enzyme-linked immunosorbent assay (ELISA) test kits became available that allow specific antibodies to be assigned to IgG subclasses. The present study was designed to establish the pattern of specific antibody responses to polysaccharide and protein antigens in a large cohort of healthy subjects from Germany. MATERIALS AND METHODSSubjects. The subjects of the present study were 313 clinically healthy children (214 males and 99 females) from 6 months to 18 years of age who were admitted to the hospital for minor surgery. Informed consent was obtained from the parents. The adult subjects were 73 healthy blood donors (36 males and 37 females) ranging from 20 to 61 years of age. Only subjects who were free of recurrent infections or inflammation, as assessed by a standardized questionnaire, and whose C-reactive protein concentrations were within the normal limit were incl...

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“…The model for development and duration of immunity against Hib disease has been reported by Auranen et al and Leino et al [29][30][31]. Immunity against Hib disease is induced by previous Hib carriage and by encounters with cross-reactive bacteria.…”

Section: Non-immunepimmunementioning

confidence: 99%

Modelling transmission, immunity and disease of Haemophilus influenzae type b in a structured population

et al. 2004

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An individual-based stochastic simulation model was constructed to study the epidemiology of Haemophilus influenzae type b (Hib) transmission, immunity and invasive disease. Embedded in a demographic model, the transmission model of Hib carriage employs the most important social mixing patterns with three types of contact sites (family, day-care group, and school class). The model includes immunity against invasive Hib disease, initiated and boosted by Hib carriage and cross-reactive bacterial encounters. The model reproduces the observed age patterns in Hib carriage and disease in Finland before large-scale use of the Hib conjugate vaccines. The model was used to investigate characteristics of Hib transmission. The analysis emphasizes transmission between children and adults in families while pointing out the importance of pre-school and school-aged children in maintaining Hib circulation. Carriage in these age groups is thus identified as being essential to target for sustained effects of interventions by vaccination.

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Haemophilus influenzae type b and cross-reactive antigens in natural Hib infection dynamics; modelling in two populations

Cited by 15 publications

References 50 publications

Modelling the effects of booster dose vaccination schedules and recommendations for public health immunization programs: the case of Haemophilus influenzae serotype b

Modelling the effects of booster dose vaccination schedules and recommendations for public health immunization programs: the case of Haemophilus influenzae serotype b

Levels of Antibodies Specific to Tetanus Toxoid,Haemophilus influenzaeType b, and Pneumococcal Capsular Polysaccharide in Healthy Children and Adults

Modelling transmission, immunity and disease of Haemophilus influenzae type b in a structured population

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