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Introduction: Côte d’Ivoire introduced the Haemophilus influenzae type b vaccine into the EPI in March 2009. Following this introduction, an evaluation was conducted in 2012 in order to evaluate the vaccine introduction process. Methods: Data collection methods consisted of document review, structured interviews and direct observation. This study collected information from six health region officials, 12 health districts and 36 healthcare institutions. Seventy-two mothers or child carers were also interviewed. Collected data were processed and analysed by Excel, Epi Info and SPSS. Results: A vaccine introduction plan was developed, but was not communicated at the operational level. The planned training for district health care providers was conducted eighteen months after introduction of the vaccine. None of the vaccinating centres had communication support about the new vaccine. Temperature recording was regularly performed in 92% of district deposits and 68% of vaccinating centres. Deteriorated vaccines were observed in 6% of vaccinating centres. Only 3.5% of parents had been informed about introduction of the vaccine. Increased immunization coverage for the third dose of pentavalent vaccine was observed in one half of health districts. Conclusion: Evaluation of the introduction of Haemophilus influenzae type b vaccine highlightsthe strengths and weaknesses of the health system and provides lessons for the introduction of other vaccines into the expanded programme on immunization.

In humans, CD27+ blood B cells with mutated immunoglobulin (Ig) receptors comprise two major populations: isotype-switched memory cells (IgG+ or IgA+CD27+) and IgM+IgD+CD27+ cells. While switched CD27+ cells are generated in germinal centers (GC) by T-dependent (TD) responses, the origin of IgM+IgD+CD27+ cells is still controversial. Data including ours support the view that these cells can develop and mutate along a GC-independent pathway and that they represent circulating marginal zone B (MZB) cells involved in T-independent (TI) responses. Our data provide evidence for a developmental diversification of these MZB cells, at least in very young children, outside of TD and TI immune responses. The identification of a human MZB cell precursor with NOTCH2-dependent differentiation properties further argue in favor of the existence of a MZB cell lineage in humans, like in rodents. At last, a role for Toll-like receptors in the development and/or maintenance of IgM+IgD+CD27+ B cells is proposed.

The aim of this study was to precise the capsular type of Haemophilus influenzae, to determine its susceptibility to beta-lactam agents, and to search for an eventual clonality between the clinical strains of the pathogen. Polymerase chain reaction was carried out to confirm the capsular type and to determine the beta-lactamase type. Minimum inhibitory concentrations (MICs) of beta-lactam agents for H. influenzae were determined by the agar dilution method on Haemophilus test medium, and the strains were analyzed by pulsed-field gel electrophoresis after SmaI restriction. Among 157 strains of H. influenzae studied, 12.1% was of serotype b. Sixty-seven strains (42.7%) were resistant to amoxicillin, among which 51 were resistant through production of TEM-type beta-lactamase while 16 showed high MICs for amoxicillin, amoxicillin + clavulanic acid, and cefuroxim, which suggested a resistance by modification of penicillin-binding proteins. Among the latter strains, five were producing TEM-type beta-lactamase. Cefotaxim, cefixim, and cefpodoxim had low MICs in all cases. The pulsed-field gel electrophoresis revealed 110 pulsotypes. All H. influenzae strains, including noncapsulated strains and serotype-b encapsulated strains, had a high level of heterogeneity, with diversity indices of respectively 0.67 and 0.94.

The incidence of Haemophilus influenzae b meningitis (Hib) in children5 years in Tunisia was studied through a surveillance system set up in June 2000 and followed for 14 months. Population-based surveillance began in 3 governorates and sentinel surveillance in 2. Children5 years suspected of meningitis had lumbar puncture, macroscopic exam, blood count, chemical analysis and culture carried out. In the 14 months, 80 cases of meningitis were recorded. From the population-based surveillance most cases were children1 year (73.6%) and boys (64%). H. influenzae was isolated in 38% of cases, pneumococci in 13% and meningococci in 7%. The incidence of confirmed Hib was 14.4/100 000 children. The estimated cost of identifying and treating Hib meningitis and its complications was greater than the cost of vaccine introduction. Based this study, the Ministry of Health has decided to introduce Hib vaccination.

Immunization against Haemophilus influenzae b and hepatitis B during infancy, as well as the administration of a second dose of measles-mumps-rubella vaccine around the age of 12, are the significant additions brought to the childhood immunization program in recent years. The availability in the near future of the acellular pertussis vaccines illustrates the efforts made to reduce the side effects associated with the use of some vaccines. The high cost of these acellular vaccines, together with the absence of combined Haemophilus influenzae or hepatitis B vaccines, represent their current limitations.

Group A streptococci (S. pyogenes) possess a number of capsule and cell wall associated components and release many extracellular proteins (toxins and hydrolytic enzymes) that are known or thought to contribute to the virulence and pathogenicity of the microorganism. Groupe A streptococci cause a wide array of infections, the most frequent of which are acute pharyngitis and pyoderma with two severe sequelae (acute rheumatic fever and glomerulonephritis). Other manifestations are scarlet fever and various soft tissue infections as well as sepsis and the recently characterized streptococcal toxic shock syndrome. The somatic components of group A streptococci include cell wall M protein, capsular hyaluronic acid, lipoteichoic acid, peptidoglycan, fibronectin binding protein, C5a peptidase and receptors for various human plasma proteins particularly IgA and IgG. The extracellular products are numerous and consist of among others the hemolytic toxins streptolysins S and O, hyaluronidase, streptokinase and cysteinyl proteinase as well as the superantigens erythrogenic toxins A and C also known as pyrogenic exotoxins.

We have made a retrospective study of invasive Hib infections which have occurred in the Children's Hospital since 1980 to the end of July 1994; and we have been able to notice that since the introduction of vaccination against Hib, especially since it is free, the incidence of invasive Hib infections in the Grand Duchy of Luxembourg is in great decline.

During the last decades, progresses in the field of vaccination entailed a better control of many infectious diseases, even to their complete or nearly complete eradication. However, progresses in this field can still be realised. This paper brings the attention of the practioners on the new trends contributing to improve, in our country, the rate of immunization owing to a better attention for applying the present vaccination schedule and introducing new vaccines.

Currently three Haemophilus influenzae type b (Hib) conjugate vaccines are licensed for use in Canada in infants 2 months of age and older: HibTITER (Lederle Laboratories), PedvaxHIB (Merck SharpDohme Canada) and Act-HIB (Pasteur-Mérieux, distributed in Canada by Connaught Laboratories Ltd.). A fourth vaccine, licensed both as a single product (ProHIBIT) or in combination with diphtheria toxoid-pertussis vaccine-tetanus toxoid (DPT-Hib) (Connaught), is limited to use in children 18 months of age or older. The following recommendations incorporate those previously published by the National Advisory Committee on Immunization(1), provide information on Act-HIB (which was licensed in March 1992) and summarize recently published data on the comparative immogenic effects and interchangeability of Hib conjugate vaccines (2-6).

Immunization with Haemophilus vaccine is undertaken to prevent invasive infections due to Haemophilus influenzae type b. Purulent meningitis is the most frequent chiefly in less than 2 years infants. Vaccine is composed of purified PRP which is poorly immunogenic and protective before two years. Actual vaccines are conjugate with protein which give them a protective and immunogenic power in very long young infants. They must be included in the schedule of infants immunizations, and fitting to other immunizations (DTP-Polio) is the best. The frequency of H. influenzae meningitis is high in tropics and those vaccines should be very useful. Cost of vaccine and inclusion in EPI are yet discussed for infants in tropical areas.

The antigenic properties of the capsule polyoside (PRP) from Haemophilus influenzae type b (Hib) are adequate to form the basis for immunization designed to prevent the severe infections caused by this organism. The tolerance and immunogenicity of a vaccine containing either 12.5 or 25 micrograms PRP were studied in 325 healthy children aged 15 to 71 months after informed consent had been obtained from the parents. Each child was given one subcutaneous injection of 0.5 ml vaccine. Antibodies against Hib were assayed before and one month after the injection. Clinical tolerance was outstanding both locally (moderate and transient pain in 13% of cases) and systematically, with only eight (2.6%) febrile reactions in excess of 38.5 degrees C within 24 hours after the injection. A very significant rise in antibody titers was seen in all age groups, but a mean titer of 1 microgram/ml was achieved only in children aged 24 months or more. No significant difference was found between the two dosages. Individual analysis showed that following immunization antibody titers reached 0.15 micrograms/ml or more in 65% of infants aged 15 to 17 months, 71% of infants aged 18 to 23 months, 80% of infants aged 24 to 30 months and 95% of children older than 30 months. Despite the inadequate immune response evidenced in the younger age groups, our results confirm that Hib infections are preventable from the age of 2 years. Our results are consistent with those recorded with a similar vaccine in Finland.

The choice of treatment, the importance of chemoprophylaxis in household contacts and the potential impact of immunization with vaccines against Haemophilus influenzae type b (Hib) currently under investigation are discussed on the basis of the patients hospitalized for invasive Hib infections at the University Children's Hospital Geneva from 1976 to 1985. Among 122 culture-proven infections due to Hib, there were 41% of cases of meningitis, 37.7% of epiglottitis, 9.8% of pneumonia, 5.7% of septicemia, 3.3% of cellulitis and 2.4% of septic arthritis. From 1981 to 1983, one strain of Hib produced beta-lactamase, but between 1984 and 1985, 5 strains (19.2%) produced beta-lactamase. Only one case of possible horizontal transmission of the infection was found in this 10-year period. We conclude that 1. the appearance of beta-lactamase producing strains of Hib requires that treatment be initiated with an antimicrobial agent resistant to beta-lactamase when a Hib infection is suspected; 2. in our region, only one case of an invasive Hib infection could theoretically have been prevented by chemoprophylaxis; and 3. the calculated theoretical impact of vaccination with the new types of vaccines against Hib could have prevented 106 of 122 cases of invasive Hib infections.