RESUMEN
OBJECTIVE: To estimate the potential health impact and cost-effectiveness of nationwide Haemophilus influenzae type b (Hib) vaccination in India. STUDY DESIGN: A decision support model was used, bringing together estimates of demography, epidemiology, Hib vaccine effectiveness, Hib vaccine costs, and health care costs. Scenarios favorable and unfavorable to the vaccine were evaluated. State-level analyses indicate where the vaccine might have the greatest impact and value. RESULTS: Between 2012 and 2031, Hib conjugate vaccination is estimated to prevent over 200â000 child deaths (â¼1% of deaths in children <5 years of age) in India at an incremental cost of US$127 million per year. From a government perspective, state-level cost-effectiveness ranged from US$192 to US$1033 per discounted disability adjusted life years averted. With the inclusion of household health care costs, cost-effectiveness ranged from US$155-US$939 per discounted disability adjusted life year averted. These values are below the World Health Organization thresholds for cost effectiveness of public health interventions. CONCLUSIONS: Hib conjugate vaccination is a cost-effective intervention in all States of India. This conclusion does not alter with plausible changes in key parameters. Although investment in Hib conjugate vaccination would significantly increase the cost of the Universal Immunization Program, about 15% of the incremental cost would be offset by health care cost savings. Efforts should be made to expedite the nationwide introduction of Hib conjugate vaccination in India.
Asunto(s)
Infecciones por Haemophilus/economía , Vacunas contra Haemophilus/economía , Haemophilus influenzae tipo b/inmunología , Programas de Inmunización/economía , Meningitis por Haemophilus/economía , Vacunas Conjugadas/economía , Cápsulas Bacterianas , Niño , Costo de Enfermedad , Análisis Costo-Beneficio , Técnicas de Apoyo para la Decisión , Infecciones por Haemophilus/inmunología , Infecciones por Haemophilus/prevención & control , Costos de la Atención en Salud , Humanos , India , Meningitis por Haemophilus/epidemiología , Meningitis por Haemophilus/inmunología , Vacunas Conjugadas/inmunologíaRESUMEN
On September 22 to 25, 2002, a group of infectious disease specialists, public health officials, and vaccine experts from 33 countries gathered in Scottsdale, Arizona, to discuss the epidemiology and control of disease caused by Haemophilus influenzae type b (Hib) in the era of Hib conjugate vaccines. This supplement is a synthesis of the major themes and key lessons identified at the meeting. The objectives of the conference were to review the 10-year experience with Hib conjugate vaccines, discuss strategies to reduce Hib disease rates to lowest possible levels in industrialized countries, review impediments to the introduction of Hib vaccine in developing countries, and discuss strategies for disseminating lessons learned from countries using to those not using Hib conjugate vaccines. Over 10 years of international experience with Hib conjugate vaccines has demonstrated that they are safe and effective. Routine use of Hib conjugate vaccine has consistently led to decreases in the incidence of invasive Hib disease of 90% or more across a wide range of epidemiologic situations in industrialized countries. In some countries, the vaccine has caused a near-disappearance of invasive Hib disease through a combination of direct protection and herd immunity. Developing countries that have implemented routine vaccination (eg, The Gambia, Chile) have also had substantial disease reduction. In countries where Hib conjugate vaccine is being used, reducing Hib disease incidence to the lowest possible level will depend on maintaining high vaccine coverage levels, conducting surveillance for Hib disease, and investigating Hib disease cases. The optimal Hib vaccination strategy will depend on many factors, including local epidemiology and programmatic considerations. In countries that are not using Hib conjugate vaccine, information on the local burden of Hib disease will be essential for leaders considering vaccine introduction. Where disease burden is high, a multifaceted approach is urgently needed to evaluate and overcome barriers to vaccine introduction. In areas where Hib disease burden is not well characterized, additional work will be needed to understand the epidemiology of Hib disease and to communicate the value of Hib conjugate vaccine.
Asunto(s)
Salud Global , Infecciones por Haemophilus/inmunología , Vacunas contra Haemophilus/uso terapéutico , Haemophilus influenzae/inmunología , Meningitis por Haemophilus/inmunología , Neumonía Bacteriana/inmunología , Niño , Países en Desarrollo , Infecciones por Haemophilus/diagnóstico , Infecciones por Haemophilus/epidemiología , Infecciones por Haemophilus/prevención & control , Vacunas contra Haemophilus/economía , Humanos , Programas de Inmunización/organización & administración , Meningitis por Haemophilus/diagnóstico , Meningitis por Haemophilus/epidemiología , Meningitis por Haemophilus/prevención & control , Neumonía Bacteriana/diagnóstico , Neumonía Bacteriana/epidemiología , Neumonía Bacteriana/prevención & control , Vacunas Combinadas/uso terapéutico , Vacunas Conjugadas/economía , Vacunas Conjugadas/uso terapéuticoRESUMEN
In 40 children with Haemophilus influenzae b (Hib) meningitis, we determined serum levels (mg/dl) of IgG subclasses using the radial immunodiffusion method; 67.8 per cent of these children were less than 24 months old. In 14 children of the sample we measured serum IgG and IgG2 anti-ribosyl-ribitolphosphate (anti-PRP) (by enzyme-linked immunosorbent assay, ELISA) in the acute and convalescent phases of the disease. Lower IgG2 levels than those of the control group were obtained in all age ranges: 3-12 months, 1-2 years (p < 0.01), and 2-5 years (p < 0.001). IgG4 was also present in lower levels in patients of all age ranges (p < 0.05, p < 0.001, and p < 0.01 respectively). Serum levels of IgG anti-PRP and IgG2 anti-PRP measured were very low in the acute phase of the disease in all age ranges and there was no notable increase in levels during the convalescent phase of the disease. This result indicates that children less than 24 months old do not produce sufficient levels of IgG and IgG2 anti-PRP even after Hib meningitis.
Asunto(s)
Inmunoglobulina G/sangre , Meningitis por Haemophilus/inmunología , Ribosamonofosfatos/inmunología , Enfermedad Aguda , Distribución por Edad , Brasil , Estudios de Casos y Controles , Preescolar , Convalecencia , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunodifusión , Inmunoglobulina G/clasificación , Lactante , Masculino , Meningitis por Haemophilus/sangreRESUMEN
In some countries, the invasive disease caused by Haemophilus influenzae type b (Hib) has been practically eliminated thanks to vaccination. However, in much of the developing world, meningitides and pneumonias caused by these bacteria continue to be a major cause of childhood morbidity and mortality, as well as high hospitalization costs. Because safe and effective conjugate vaccines are now available, the Special Program for Vaccines and Immunization of the Pan American Health Organization has recommended introducing them into the regular vaccination regimen of as many countries as possible. This has been done in Chile and Uruguay, where the Hib vaccine now forms part of the regular vaccination routine. When the vaccine was being introduced, both countries had difficulties they could have avoided if they had known of the experiences of other nations. Therefore, these two countries now offer the lessons they learned to other nations considering introducing the vaccine into their immunization programs. The most important lessons were to: strengthen the epidemiological surveillance system sufficiently in advance of introducing the vaccine; with the support of scientific societies, present the technical information that justifies introducing the vaccine; seek community backing and acceptance; precisely establish in advance the presentation and dosage of the vaccine that is most appropriate for the country; and be certain to have the political and legal decisions needed to ensure the continuity of Hib vaccination in the future.
Asunto(s)
Haemophilus influenzae tipo b/inmunología , Meningitis por Haemophilus/epidemiología , Vacunas Conjugadas , Niño , Preescolar , Chile/epidemiología , Femenino , Humanos , Esquemas de Inmunización , Lactante , Masculino , Meningitis por Haemophilus/inmunología , Meningitis por Haemophilus/prevención & control , Uruguay/epidemiología , VacunaciónRESUMEN
Between 1979 and 1994, epidemiological surveillance of meningitides in Uruguay showed a progressive increase in suppurative meningitides due mainly to Neisseria meningitidis and Haemophilus influenzae type b (Hib). The cases were concentrated in children under 5; however, among the cases caused by Hib, 70% affected children from 1 to 11 months old. Facing this situation, the Ministry of Public Health resolved, as of August 1994, to include the Hib vaccine in the country's Expanded Program on Immunization, which has been in place since 1982. The Hib vaccination is done without charge and is obligatory for all children under 5 years of age. It is done using the following series of vaccinations: a) three doses, given at 2, 4, and 6 months, with a booster dose at age 1; b) children from 7 to 11 months old receive two doses two months apart and a booster dose a year later; and c) a single dose for children 12 months to 4 years old. Between August and December 1994 a coverage rate of 76.6% was reached among children between 2 months and 4 years old, and the coverage has remained above 80% in the new cohorts. In Uruguay, this vaccination strategy had a spectacular impact on morbidity and mortality due to meningitides caused by Hib. One of the results was that the incidence of 15.6 per 100,000 registered in children under 5 in the prevaccination years declined to 0.03 per 100,000 in 1996.
Asunto(s)
Vacunas contra Haemophilus/administración & dosificación , Haemophilus influenzae tipo b/inmunología , Programas de Inmunización , Meningitis por Haemophilus/epidemiología , Preescolar , Femenino , Vacunas contra Haemophilus/inmunología , Humanos , Esquemas de Inmunización , Incidencia , Lactante , Masculino , Meningitis por Haemophilus/inmunología , Meningitis por Haemophilus/prevención & control , Uruguay/epidemiología , VacunaciónRESUMEN
Haemophilus influenzae is still one of the main causes of diverse invasive diseases in children in México. Epidemiologic data indicate that these processes affect primarily the central nervous system and the respiratory tract. Several factors are involved in the expression of infectious disease by this organism, among them the pathogenic determinants of the parasite and those related with resistance in the host. Occurrence of disease is usually the result of the interaction between these determinants. Knowledge of these pathogenic determinants of the parasite and of factors involved in the immune response of the host have allowed an understanding of the infectious process and have directed research in a least three areas: 1) identification of bacterial membrane fractions related with diagnosis of the disease, 2) screening for immunogenic components in the bacterias as vaccine candidates to be used in the prevention of the disease and, 3) the planning of appropriate alternatives for specific antimicrobial therapy.
Asunto(s)
Infecciones por Haemophilus/etiología , Haemophilus influenzae , Vacunas Bacterianas/inmunología , Infecciones por Haemophilus/epidemiología , Infecciones por Haemophilus/inmunología , Infecciones por Haemophilus/prevención & control , Haemophilus influenzae/inmunología , Meningitis por Haemophilus/epidemiología , Meningitis por Haemophilus/etiología , Meningitis por Haemophilus/inmunología , México/epidemiologíaRESUMEN
Haemophilus influenzae serotipo b es el principal agente etiológico de meningitis bacteriana endémica en población infantil. Aproximadamente 80% de los casos con este padecimiento ocurre entre los dos a tres meses de edad y al final del tercer año de vida; el 20% restante habitualmente se presenta en niños de tres a seis años de edad; los adultos son raramente afectados. Actualmente en Estados Unidos la meningitis bacteriana tipo b ocurre con una tasa anual entre 19 a 63 por 100.000 niños menores de cinco años de edad. Existen datos que estiman que uno de cada 250 niños es susceptible de contraer la enfermedad antes de los cinco años de edad
Asunto(s)
Lactante , Preescolar , Niño , Ratones , Animales , Humanos , Vacunas Bacterianas , Haemophilus influenzae/inmunología , Meningitis por Haemophilus/inmunologíaRESUMEN
We studied Haemophilus influenzae type b meningitis in 68 patients to evaluate whether quantitative determination of PRP in body fluids obtained at admission or measurement of the duration of its presence helped identify patients at risk for complications. Geometric mean admission PRP concentrations in CSF, blood, and urine increased with severity of disease, but individual values varied greatly. Measurements of the duration of antigenemia and antigenuria also varied widely and were best predicted by the admission or peak PRP concentration. The mean duration of both antigenemia and antigenuria increased with severity of disease. In contrast, the elimination half-life of PRP did not differ significantly with severity of hospital course, peak PRP concentration in blood or urine, or patient age. Clearance from CSF could not be accurately assessed, but PRP was detectable in only six of 41 patients in whom spinal fluid was obtained after the eighth day of hospitalization; all had complicated courses. Although latex particle agglutination assay is a valuable aid in rapid diagnosis of invasive Hib infections, the predictive value of antigen quantitation at admission and the determination of its duration in body fluids is limited by the wide range of observed values.
Asunto(s)
Meningitis por Haemophilus/inmunología , Polisacáridos Bacterianos/análisis , Polisacáridos/análisis , Pruebas de Aglutinación , Antibacterianos/uso terapéutico , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Cinética , Masculino , Meningitis por Haemophilus/tratamiento farmacológico , Polisacáridos/metabolismo , Polisacáridos Bacterianos/metabolismo , Pronóstico , Estudios ProspectivosRESUMEN
Siblings of patients with type b Haemophilus influenzae meningitis are at increased risk of developing Haemophilus disease. We immunized 26 healthy siblings and 25 control subjects using a vaccine containing the type b polysaccharide capsule (10 micrograms PRP) and pertussis vaccine (4 opacity units) (Lederle Laboratories) to determine whether siblings of patients with Haemophilus meningitis had an impaired antibody response to PRP. Using two intramuscular injections one month apart, we found that the siblings had a lower response to PRP. One month after the second injection, 12 of 24 of the siblings had serum concentrations of anticapsular (PRP) antibody thought to be sufficient to confer protection against Haemophilus disease (greater than or equal to 300 ng/ml), compared with 19 of 24 of the control children tested (50% vs 79%, P = 0.035 by chi-square analysis). In comparison with the normal controls, the siblings produced significantly less IgG anti-PRP antibody but similar amounts of IgM. The impaired responsiveness to PRP was most evident among the 16 children born after their sibling had meningitis and who were not known to have been exposed to type b Haemophilus infection previously. These data indicate that siblings of some patients with type b Haemophilus meningitis have reduced ability to form IgG anti-PRP antibody, which may be associated with increased susceptibility to Haemophilus disease.
Asunto(s)
Formación de Anticuerpos , Vacunas Bacterianas/inmunología , Haemophilus influenzae/inmunología , Meningitis por Haemophilus/genética , Polisacáridos Bacterianos/inmunología , Anticuerpos Antibacterianos/análisis , Humanos , Inmunoglobulina G/análisis , Inmunoglobulina M/análisis , Lactante , Meningitis por Haemophilus/inmunología , Vacuna contra la Tos Ferina/inmunologíaAsunto(s)
Antígenos Bacterianos/líquido cefalorraquídeo , Contrainmunoelectroforesis/métodos , Haemophilus influenzae/inmunología , Inmunoelectroforesis/métodos , Meningitis por Haemophilus/líquido cefalorraquídeo , Electroforesis en Gel de Poliacrilamida/métodos , Humanos , Meningitis por Haemophilus/inmunologíaRESUMEN
Fifty children with Hemophilus influenzae meningitis have been enrolled in a prospective study. Patients were randomly assigned chloramphenicol or ampicillin treatment; there were no significant differences between groups in other respects. Countercurrent immunoelectrophoresis proved to be a valuable tool for rapid diagnosis of the causative agent even in pretreated patients. Increasing quantities of capsular polyribosephosphate antigen detected in the initial cerebrospinal fluid correlated significantly (r=0.62419; p less than 0.01) with early and late sequelae of meningitis. None of the patients died. Severe and persistent neurologic or intellectual deficits were noted in four (8%) of the children, and an additional 14 (28%) had IQ scores between 70 and 90. The presence of bactericidal antibody in serum was not protective. Anti-PRP antibody generally was not present in acute serum specimens and irrespective of the quantity of antigenic stimulus provided by the disease was nondetectable in 21 of 24 children less than 17 months of age following recovery.
Asunto(s)
Ampicilina/uso terapéutico , Cloranfenicol/uso terapéutico , Meningitis por Haemophilus/tratamiento farmacológico , Adolescente , Anticuerpos Antibacterianos/análisis , Antígenos Bacterianos/líquido cefalorraquídeo , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Inteligencia , Masculino , Meningitis por Haemophilus/complicaciones , Meningitis por Haemophilus/inmunología , Estudios Prospectivos , Convulsiones/etiología , Efusión Subdural/etiologíaRESUMEN
Five cases of HITB maningitis occurred within six months in an enclosed population of 28 to 32 chronically ill children. Studies of nasopharyngeal carriage and serum HITB anticapsular antibodies were started after the third case occurred. Two patients had low (less than 0.04 and 0.05mug/ml) antibodies and were not carriers when studied prior to onset of their disease. The carriage rate was approximately 20% among the children. Carriage was usually prolonged, and acquisition was not prevented by high antibody levels. Attempts to arrest this outbreak with type b polysaccharide immunization and ampicillin therapy are discussed in the context of HITB meningitis as a contagious disease.