scholarly journals Dynamics of natural immunity caused by subclinical infections, case study on Haemophilus influenzae type b (Hib)

2000 ◽  
Vol 125 (3) ◽  
pp. 583-591 ◽  
Author(s):  
T. LEINO ◽  
K. AURANEN ◽  
P. H. MÄKELÄ ◽  
H. KÄYHTY ◽  
A. K. TAKALA
Keyword(s):  
Haemophilus Influenzae ◽  
Invasive Disease ◽  
Haemophilus Influenzae Type ◽  
Antibody Concentration ◽  
Natural Immunity ◽  
Type B ◽  
Force Of Infection ◽  
Invasive Infections ◽  
Disease Antibody ◽  
Antibody Levels

Natural immunity to Haemophilus influenzae type b (Hib) is based primarily on antibodies that are thought to develop in response to subclinical infections. Wide use of conjugated Hib vaccines could lead to decreases in circulating Hib bacteria, thereby diminishing antibody levels in the unvaccinated. We applied a statistical model to estimate the duration of natural immunity to Hib under different forces of infection. Prior to the introduction of conjugated Hib vaccines, new Hib infections were estimated to occur once in 4 years and the antibody concentration to stabilize at a level around 1 μg/ml. In the absence of new stimuli, i.e. infection, 57% of the unvaccinated population would become susceptible to invasive disease (antibody levels < 0·15 μg/ml) in 10 years. Due to an interaction between the force of infection and the duration of immunity, in some situations numbers of invasive infections could increase in unvaccinated cohorts. This theoretical scenario has yet to be observed in practice.

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

2002 ◽  
Vol 129 (1) ◽  
pp. 73-83 ◽  
Author(s):  
T. LEINO ◽  
K. AURANEN ◽  
P. H. MÄKELÄ ◽  
H. KÄYHTY ◽  
M. RAMSAY ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Age Distribution ◽  
Invasive Disease ◽  
Haemophilus Influenzae Type ◽  
Natural Immunity ◽  
Type B ◽  
Infection Dynamics ◽  
Wide Scale ◽  
The Uk ◽  
Two Populations

Natural immunity to Haemophilus influenzae type b (Hib) invasive disease is based on antibodies arising in response to encounters with Hib or cross-reactive (CR) bacteria. The relative importance of Hib and CR contacts is unknown. We applied a statistical model to estimate the total rate of immunizing infections of Hib and CR prior to wide-scale vaccinations in Finland and the UK. The average rates of these contacts were 0.7 and 1.2 per year per child in Finland and the UK, respectively. Using a rough estimate of 0.1 Hib acquisitions per year per child in the UK based on carriage rates, the proportion of Hib among all immunizing contacts was in the order of 10%, suggesting that CR bacteria have a major role. In general, varying frequency of CR contacts may explain some differences in the pre-vaccination incidence and age-distribution of invasive disease in different countries.

scholarly journals Anti-Polyribosylribitol Phosphate Antibody Concentrations and Avidities in Children since the Start of Haemophilus influenzae Type b Immunization of Infants in the United Kingdom

2008 ◽  
Vol 16 (2) ◽  
pp. 246-252 ◽  
Author(s):  
Dominic F. Kelly ◽  
E. Richard Moxon ◽  
Ly-Mee Yu ◽  
Andrew J. Pollard
Keyword(s):  
United Kingdom ◽  
Haemophilus Influenzae ◽  
Invasive Disease ◽  
Haemophilus Influenzae Type ◽  
Antibody Concentration ◽  
Type B ◽  
Conjugate Vaccines ◽  
Factors Affecting ◽  
The United Kingdom ◽  
Polyribosylribitol Phosphate

ABSTRACT The introduction of routine infant immunization with Haemophilus influenzae type b (Hib) conjugate vaccines in the United Kingdom in 1992 led to a significant reduction in invasive disease due to this organism. Subsequently, between 1999 and 2003 there was an increase in the number of immunized children with Hib infection. We investigated whether the rise in cases was related to changes in anti-polyribosylribitol phosphate (PRP) antibody concentration or avidity. Using stored sera, we analyzed temporal changes in antibody levels among 3- to 5-year-old children immunized between 1991 and 2000. Anti-PRP antibody concentrations were higher in 3- to 5-year-olds who received infant immunization in 1991 than those in subsequent years. This difference may be related to changes in either the mode of administration of Hib conjugate vaccines or the rates of Hib nasopharyngeal carriage. This study emphasizes the factors affecting anti-PRP antibody concentration following immunization with conjugate vaccines and the importance of these in long-term protection from invasive disease.

scholarly journals Levels of Antibodies Specific to Tetanus Toxoid, Haemophilus influenzae Type b, and Pneumococcal Capsular Polysaccharide in Healthy Children and Adults

2003 ◽  
Vol 10 (2) ◽  
pp. 202-207 ◽  
Author(s):  
Uwe Schauer ◽  
Frank Stemberg ◽  
Christian H. L. Rieger ◽  
Wolfgang Büttner ◽  
Michael Borte ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Specific Antibody ◽  
Tetanus Toxoid ◽  
Capsular Polysaccharide ◽  
Haemophilus Influenzae Type ◽  
Natural Immunity ◽  
Reference Ranges ◽  
Healthy Children ◽  
Type B ◽  
Antibody Levels

ABSTRACT 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.

scholarly journals Impact of Haemophilus influenzae type b conjugate vaccination on hospitalization for invasive disease in children fifteen years after its introduction in Italy

Vaccine ◽  
2017 ◽  
Vol 35 (46) ◽  
pp. 6297-6301 ◽  
Author(s):  
Domenico Martinelli ◽  
Chiara Azzari ◽  
Paolo Bonanni ◽  
Susanna Esposito ◽  
Elisabetta Franco ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Invasive Disease ◽  
Haemophilus Influenzae Type ◽  
Haemophilus Influenzae Type B ◽  
Type B ◽  
Conjugate Vaccination

Immunogenicity of Haemophilus influenzae Type b Polysaccharide-Neisseria meningitidis Outer Membrane Protein Conjugate Vaccine in 2- to 6-Month-Old Infants

PEDIATRICS ◽  
1987 ◽  
Vol 80 (2) ◽  
pp. 283-287
Author(s):  
Allen A. Lenoir ◽  
Paul D. Granoff ◽  
Dan M. Granoff
Keyword(s):  
Membrane Protein ◽  
Haemophilus Influenzae ◽  
Neisseria Meningitidis ◽  
Outer Membrane Protein ◽  
Geometric Mean ◽  
Serum Antibody ◽  
Haemophilus Influenzae Type ◽  
Antibody Concentration ◽  
Haemophilus Influenzae Type B ◽  
Type B

Fifty infants, 2 to 6 months of age, were vaccinated with Haemophilus influenzae type b capsular polysaccharide covalently linked to an outer membrane protein from Neisseria meningitidis group B. Subjects were given two injections and were randomly assigned to receive the injections separated by 1 or 2 months. Each dose contained 15 µg of polysaccharide and 51 µg of protein, or approximately twice the amount of polysaccharide as used in our previous trial (Lancet 1986;2:299). Fevers of 38.0° to 38.8°C developed in three infants (6%) within 24 hours after vaccination, but there were no other notable reactions. Following one injection, the geometric mean antibody concentration increased from 0.13 µg/mL in preimmune serum to 1.50 µg/mL in serum obtained 1 to 2 months later (P &lt; .001). After a second injection, there was a further increase in serum antibody (geometric mean = 3.11 µg/mL, P &lt; .007). The geometric mean antibody concentration of the group reimmunized 2 months after the first injection was higher than that in the group reimmunized after 1 month (3.95 v 2.32 µg/mL, P = .05, by analysis of covariance with age as the covariant). These data confirm our previous preliminary observations on the safety and immunogenicity of this new conjugate vaccine in infants 2 to 6 months of age. The data suggest that a 2-month interval between the first and second injections results in higher levels of serum antibody than a 1-month interval.

Epidemiology of Haemophilus Type B Invasive Disease in Childhood in Glasgow

1993 ◽  
Vol 38 (1) ◽  
pp. 18-20 ◽  
Author(s):  
A Coggins ◽  
C.W. Shepherd ◽  
F. Cockburn
Keyword(s):  
Haemophilus Influenzae ◽  
Invasive Disease ◽  
Annual Incidence ◽  
Childhood Vaccination ◽  
Haemophilus Influenzae Type ◽  
Haemophilus Influenzae Type B ◽  
Type B ◽  
Neurological Sequelae ◽  
The United Kingdom

The objective of this study was to investigate the epidemiology of invasive disease due to Haemophilus influenzae type b in childhood in Glasgow. A retrospective study has been made on the hospital records of 252 children aged 0 to 12 years admitted to Glasgow hospitals during 1981–1990. The annual incidence of invasive Haemophilus influenzae type b disease in Glasgow was estimated at 39 per 100,000 children less than five years of age per year. The figure for Haemophilus meningitis was 23.8 per 100,000 children less than five years of age per year. Ninety-five per cent of all cases occurred in children less than five years of age and 72.1% of meningitis cases occurred before two years of age. There was a mortality of 2.77%. Long-term neurological sequelae were found in 15.3% of the survivors. The annual incidence of Haemophilus influenzae type b disease is slightly higher in Glasgow than previously reported for the United Kingdom. The study provides baseline data to help assess efficacy of proposed early childhood vaccination.

Interchangeability of Haemophilus influenzae Type b vaccines in the Primary Series: Evaluation of a Two-dose Mixed Regimen

PEDIATRICS ◽  
1996 ◽  
Vol 98 (5) ◽  
pp. 898-904 ◽  
Author(s):  
Kathleen M. Bewley ◽  
Joel G. Schwab ◽  
Gerard A. Ballanco ◽  
Robert S. Daum
Keyword(s):  
Haemophilus Influenzae ◽  
Randomized Clinical Trials ◽  
Geometric Mean ◽  
Serum Antibody ◽  
Area Under The Curve ◽  
Haemophilus Influenzae Type ◽  
Antibody Concentration ◽  
Haemophilus Influenzae Type B ◽  
Type B ◽  
Series Evaluation

Objective. To evaluate two- or threedose "mixed" regimens of Haemophilus influenzae type b conjugate vaccines in the priming series. Design. Two randomized clinical trials with 140 and 181 infants, respectively. Setting. Private practices in New Orleans and Chicago. Methods. In trial I, infants received one of four regimens. Two were recommended regimens for polyribosylribitol phosphate (PRP)—meningococcal protein conjugate (M) and PRP—tetanus toxoid conjugate (T). Two mixed regimens consisted of M at 2 months followed by two doses of T or PRP—diphtheria toxoid conjugate (D) at 4 and 6 months. Trial II consisted of three groups. Two were recommended regimens for M and T. The third was a two-dose mixed regimen consisting of M at 2 months and T at 4 months. Parents were interviewed and instructed to record side effects after each vaccination. Serum was assayed for H influenzae type b anticapsular antibody (anti-PRP). Results. Minor differences in safety profiles likely reflected α error. In trial I, M (lot 0884T, one of several known to have had decreased immunogenicity), probably primed for substantial increase in serum antibody when D or T was given at 4 and 6 months. In trial II, infants who received the two-dose mixed regimen (M from immunogenic lot 0116W at 2 months and T at 4 months) had a significantly higher mean area under the curve than recipients of the three-dose TIT regimen when antibody concentration was plotted against age, although the geometric mean anti-PRP antibody concentration for the MT-recipients was significantly lower at 7 months. Conclusions. M used in trial I may have primed infants despite poor immunogenicity. The two-dose mixed regimen (MT-) in trial II produced a mean anti-PRP antibody concentration with higher sustained anti-PRP concentrations from 2 to 7 months, as judged by the area under the curve, but a lower mean anti-PRP antibody concentration at 7 months.

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