Hemophilus influenzae bacteremia in children with sickle cell disease

Conjugate Haemophilus influenzae type b vaccines for sickle cell disease

BACKGROUND

People affected with sickle cell disease (SCD) are at high risk of infection from Haemophilus influenzae type b (Hib). Before the implementation of Haemophilus influenzae type b conjugate vaccination in high-income countries, this was responsible for a high mortality rate in children under five years of age. In African countries, where coverage of this vaccination is still extremely low, Hib remains one of the most common causes of bacteraemias in children with SCD. The increased uptake of this conjugate vaccination may substantially improve the survival of children with SCD. This is an update of a previously published Cochrane Review.

OBJECTIVES

The primary objective was to determine whether Hib conjugate vaccines reduce mortality and morbidity in children and adults with SCD.The secondary objectives were to assess the following in children and adults with SCD: the immunogenicity of Hib conjugate vaccines; the safety of these vaccines; and any variation in effect according to type of vaccine, mode of administration (separately or in combination with other vaccines), number of doses, and age at first dose.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched trial registries (04 July 2018) and contacted relevant pharmaceutical companies to identify unpublished trials.Date of last search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinoapthies Trials Register: 18 December 2017.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs comparing Hib conjugate vaccines with placebo or no treatment, or comparing different types of Hib conjugate vaccines in people with SCD.

DATA COLLECTION AND ANALYSIS

No trials of Hib conjugate vaccines in people with SCD were found.

MAIN RESULTS

There is an absence of evidence from RCTs relating to the subject of this review.

AUTHORS' CONCLUSIONS

There has been a dramatic decrease in the incidence of invasive Hib infections observed in the post-vaccination era in people with SCD living in high-income countries. Therefore, despite the absence of evidence from RCTs, it is expected that Hib conjugate vaccines may be useful in children affected with SCD, especially in African countries where there is a high prevalence of the disease. The implementation of childhood immunisation schedules, including universal Hib conjugate vaccination, may substantially improve the survival of children with SCD living in low-income countries. We currently lack data to evaluate the potential effect of Hib vaccination among unvaccinated adults with SCD. Further research should assess the optimal Hib immunisation schedule in children and adults with SCD.

Conjugate Haemophilus influenzae type b vaccines for sickle cell disease

BACKGROUND

People affected with sickle cell disease are at high risk of infection from Haemophilus influenzae type b. Before the implementation of Haemophilus influenzae type b conjugate vaccination in high-income countries, this was responsible for a high mortality rate in children under five years of age. In African countries, where coverage of this vaccination is still extremely low, Haemophilus influenzae type b remains one of the most common cause of bacteraemias in children with sickle cell disease. The increased uptake of this conjugate vaccination may substantially improve the survival of children with sickle cell disease.

OBJECTIVES

The primary objective was to determine whether Haemophilus influenzae type b conjugate vaccines reduce mortality and morbidity in children and adults with sickle cell disease.The secondary objectives were to assess the following in children and adults with sickle cell disease: the immunogenicity of Haemophilus influenzae type b conjugate vaccines; the safety of these vaccines; and any variation in effect according to type of vaccine, mode of administration (separately or in combination with other vaccines), number of doses, and age at first dose.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also contacted relevant pharmaceutical companies to identify unpublished trials.Date of last search: 23 November 2015.

SELECTION CRITERIA

All randomised and quasi-randomised controlled trials comparing Haemophilus influenzae type b conjugate vaccines with placebo or no treatment, or comparing different types of Haemophilus influenzae type b conjugate vaccines in people with sickle cell disease.

DATA COLLECTION AND ANALYSIS

No trials of Haemophilus influenzae type b conjugate vaccines in people with sickle cell disease were found.

MAIN RESULTS

There is an absence of evidence from randomised controlled trials relating to the subject of this review.

AUTHORS' CONCLUSIONS

There has been a dramatic decrease in the incidence of invasive Haemophilus influenzae type b infections observed in the post-vaccination era in people with sickle cell disease living in high-income countries. Therefore, despite the absence of evidence from randomised controlled trials, it is expected that Haemophilus influenzae type b conjugate vaccines may be useful in children affected with sickle cell disease, especially in African countries where there is a high prevalence of the disease. The implementation of childhood immunisation schedules, including universal Haemophilus influenzae type b conjugate vaccination, may substantially improve the survival of children with sickle cell disease living in low-income countries. We currently lack data to evaluate the potential effect of Haemophilus influenzae type b vaccination among unvaccinated adults with sickle cell disease. Further research should assess the optimal Hib immunisation schedule in children and adults with sickle cell disease.

Risk of infection and death among post-splenectomy patients

OBJECTIVES

The true incidence of post-splenectomy sepsis remains undetermined.

METHODS

An English literature review on post-splenectomy sepsis was undertaken by means of databases of MEDLINE for the period 1966-96. The data registered included age at splenectomy, indication for splenectomy, incidence of infection and death, interval between splenectomy and infection, and microbial aetiology.

RESULTS

The reports include 19 680 patients having undergone splenectomy with a median follow up of 6.9 years. The incidence of infection after splenectomy was 3.2% and the mortality rate was 1.4%. Only 6942 reports were sufficiently detailed to allow useful analysis. The incidence of infection among children and adults was similar, 3.3% and 3.2%, respectively. However, the death rates among children were higher than adults (1.7% vs. 1.3%). The incidence of infection was highest among patients with thalassemia major (8.2%), and sickle-cell anaemia (7.3%). The highest mortality rates were observed among patients with thalassaemia major (5.1%), and sickle-cell anaemia (4.8%).

CONCLUSION

The incidence of sepsis among post-splenectomy patients is low, however, it carries a high mortality rate especially among children with hematological disorders.

Retrospective review of osteoarticular infections in a pediatric sickle cell age group

Patients with sickle cell disease have been documented to be particularly susceptible to osteoarticular infections. Controversy exists concerning the bacteriology, etiology, and clinical presentation in differentiating osteoarticular infections from bone infarct. We retrospectively reviewed all cases from our institution over the past 22 years of osteoarticular infections in children who carry the diagnosis of sickle cell disease. Two thousand consecutive patient charts of children enrolled in the Pediatric Sickle Cell Clinic of our institution between 1973 and 1995 were evaluated. There were 14 cases of bone or joint infections (10 osteomyelitis, four septic arthritis). There was one case of multicentric osteomyelitis and one case of meningitis complicating the septic arthritis. There were nine male and five female patients with ages ranging from 6 months to 17 years (mean, 8.0). All patients were noted to have hemoglobin SS. The predominant presenting symptoms were pain (79% of cases) and swelling (71% of cases). The most frequent physical findings were fever >38.2 degrees C (71% of cases) and tenderness (86% of cases). Ninety-three percent of the children had a white blood count exceeding 15,000/mm3 (range, 7,900-32,300). Westergren sedimentation rates ranged from 14 to 89 mm/h with 93% of the children exceeding the normal value in our hospital. Cultures were positive in 75% of tissue biopsies, 58% of the blood cultures, and 70% of the bone or joint aspirates. The most common offending organism found in osteomyelitis was Salmonella (eight of 10 cases); however, no predominant organism found was identified in cases of septic arthritis. Radiographs and bone scans were of limited value in the differential diagnosis between osteoarticular infections and bone infarction. Early diagnosis and treatment of osteoarticular infections is key to satisfactory outcome. This study suggests that an ill-appearing patient with a fever >38.2 degrees C, pain, and swelling should prompt the physician to aspirate or biopsy the area and not rely on diagnostic studies that we found to be unreliable.

Low number of antibody producing cells in patients with sickle cell anemia

B cell function is impaired in patients with sickle cell anemia. Although the number of surface IgM positive cells was similar in sickle cell patients and controls, in vitro spontaneous IgM, and PWM stimulated IgA, IgM, and IgG synthesis was significantly lower in the patients than in controls. The number of PWM induced and antigen specific immunoglobulin producing cells after immunization with Pneumovax, containing 21 serotypes of Streptococcus pneumoniae, was about 100-fold lower in the patients as compared with controls. Finally, the ability of the patients' peripheral blood mononuclear cells to proliferate in response to mitogens (PWM, SAC, PHA) was diminished. Because of the observed impairments in both nonspecific and antigen specific immunoglobulin synthesis and cell proliferation assays in the patients, we determined serum concentrations of IL-4 and IL-6, two cytokines associated with antibody production. IL-4 concentrations appeared low in sickle cell patients, and correlated with that of serum IgM. We hypothesize that B cell maturation in sickle cell patients is arrested at an IL-4 dependent stage.

Lymphocyte blastogenic responses in sickle cell disease

Cell mediated immunity (CMI) has not been extensively studied in sickle cell disease (SCD). In this study, an assessment of lymphocyte blastogenic responses was done in 62 SCD patients (62 steady state and 25 in crisis with or without documented infection), along with 30 normal controls in good health and 10 with various infections. The mitogen phytohemagglutinin (PHA) and two antigens (Candida albicans and Tetanus Toxoid) were used as stimuli. An evaluation of these results by stimulation index revealed 53/62 (86%) of SCD steady state patients, 30/30 (100%) of healthy controls and 7/10 (70%) of normal control patients with infection positively responded to all three stimuli. Conversely, only 5/25 (20%) of SCD crisis state patients had totally normal blastogenic responses. Analysis of the data from SCD crisis patients revealed 14/20 (70%) with abnormally depressed proliferation to PHA, 11/20 (55%) to Candida and 6/20 (30%) to Tetanus. When comparisons were made by mean counts per minute, the most striking finding was the PHA response in the SCD crisis state. In this group the mean counts per minute were significantly less than the three other groups by statistical analysis. This data suggests that the crisis state, especially when associated with infection, profoundly effects blastogenic responses to PHA and to a lesser degree in vitro antigenic stimulation. The normal group with infection showed similar diminished blastogenesis to antigen, but no effect on mitogen response.

Splenic function in Saudi children with sickle cell disease

Splenic function was studied in 15 Saudi children with homozygous sickle cell disease. Age range was 4-13 years. Using 99Tc liver spleen scan, it was shown that 13 patients had some splenic function ranging from minimal to normal. This is in contrast to the black sicklers who usually have anatomic asplenia by the age of six to eight years. It might contribute to the relatively mild course in children with sickle cell disease in the eastern province of Saudi Arabia.

Sickle cell disease and infection

Overwhelming infections caused by encapsulated bacteria, salmonella spp. and Plasmodium falciparum (in malarious areas) are an important cause of morbidity and death in patients with sickle cell disease. Bacterial infections afflicting these patients include fulminant meningitis and septicaemia caused by Str. pneumoniae and H. influenzae type b, and non-typhoid salmonellosis. Children less than five years of age are at greatest risk for meningitis and septicaemia, while salmonella osteomyelitis is probably common to all age groups. The most important contributing factors to this increased susceptibility to encapsulated bacteria are: a state of functional asplenia, an opsonophagocytic defect due to an abnormality of the alternative complement pathway, and a deficiency of specific circulating antibodies. Devitalisation of gut and bone due to repetitive vaso-occlusive crises, saturation of the macrophage system with red cell breakdown products of chronic haemolysis, and underlying splenic and hepatic dysfunction all predispose to salmonella infections. Seventy per cent of septicaemias and meningitis among under-fives with sickle cell disease is caused by Str. pneumoniae. Septicaemia frequently presents with sudden fever, few prodromal features, and a deceptive appearance of well-being, followed within hours by rapid relentless progression to shock and death. Adrenal haemorrhage is common, and mortality can be as high as 50 per cent, unless intravenous antibiotic, with or without steroid therapy, is promptly initiated. The clinical presentation of bacterial meningitis, its management and mortality follow the normal patterns, but recurrent meningitis and cerebrovascular morbidity are common in patients with sickle cell disease. An acute pulmonary involvement, indistinguishable from bacterial pneumonia (the 'chest syndrome') is the commonest single complication of sickle cell disease at any age. Str. pneumoniae is responsible for about half of the episodes. The protective values of the pneumococcal vaccine and long-term penicillin prophylaxis remain to be established in sickle cell disease. Over 70 per cent of haematogenous osteomyelitis in sickle cell disease is caused by salmonellae. The distinction from vaso-occlusive bone crisis is often difficult, but the presence of multiple, often symmetrical bone involvement, diaphyseal fissuring and involucrum should suggest osteomyelitis rather than bone infarction. Chloramphenicol remains the drug of choice and often has to be given in high doses for up to six weeks. The role of surgery is limited by the presence of multiple bone involvement and the known anaesthetic risks in this group.(ABSTRACT TRUNCATED AT 400 WORDS)

Pneumococcal and other infections in children with sickle-cell hemoglobin C (SC) disease

The pattern of infection was compared in 139 children with sickle cell-hemoglobin C (SC) disease and in 250 control children with a normal hemoglobin (AA) genotype ascertained at birth and followed prospectively for periods of zero to six years. Both infection incidence rates and survival curve analysis indicated highly significant increases in serious infection among children with SC disease. Respiratory infection and gastroenteritis were the most common infections, but only respiratory infections were significantly more frequent in SC disease. Pneumococcal bacteremia was confined to the SC group. No hematologic differences were apparent between SC patients with and without a history of serious infection, but infection was significantly more common in patients manifesting early splenomegaly.

Systemic Hemophilus influenzae infection. A study of risk factors

In Omaha, from 1974 to 79, 30 (12.5%) of 240 patients with Haemophilus influenzae bacteremia or meningitis had a wide variety of conditions known to be associated with increased susceptibility to bacterial infection. Neonates and adults accounted for 47 per cent of the infections. Non-type b and non-typable strains caused 41 per cent of the episodes. Forty-one per cent of patients had bacteremia with no detectable focus of infection. The incidence of meningitis was low. Mortality was 28 per cent, considerably higher than in patients who were previously healthy. A review of the medical literature indicated that low-birth weight infants and patients with leukemia and other malignancies undergoing chemotherapy, splenectomy, congenital asplenia, sickle cell anemia, immunoglobulin deficiency diseases, cerebrospinal fluid shunts, and skull defects are at greater risk for systemic H. influenzae disease than the general population.

Polyvalent pneumococcal-polysaccharide immunization of patients with sickle-cell anemia and patients with splenectomy

To reduce the risk of infection from Streptococcus pneumoniae in hyposplenic patients we administered octavalent pneumococcal vaccine to 77 patients with sickle-cell disease and 19 asplenic persons and compared their response with 82 controls (38 age-matched normal persons and 44 normal black African children). Fifty micrograms each of pneumococcal-polysaccharide Types 1, 3, 6, 7, 14, 18, 19, and 23 were administered subcutaneously. Post-immunization serums (three to four weeks) were available from 52 of 77 patients with sickle-cell disease; the percent responding and the magnitude of the indirect hemagglutination response were comparable to those of the controls. Within two years after immunization we observed eight Str. pneumoniae infections in 106 age-matched unimmunized patients with sickle-cell disease, but none in the 77 immunized (P less than 0.025). We conclude that pneumococcal polysaccharides are immunogenic in hyposplenic patients and may protect against systemic Str. pneumoniae infection.

Sepsis and congenital asplenia

Fifty-nine children with congenital asplenia were reviewed for episodes of severe infection. Seven children had isolated asplenia and 52 had asplenia associated with complex congenital heart disease (asplenia syndrome). A control group of eusplenic children with comparable cardiac lesions were assembled and used for comparative statistical analysis. There were 16 instances of documented sepsis among 59 children (27%). In those less than six months of age, the invading organism was usually gram-negative (Escherichia coli or Klebsiella). In children six months of age or older, the infecting organism was usually a pneumococcus or H. influenzae. When those with asplenia syndrome were compared to the control population, the former group had a significantly greater incidence of sepsis. Children with asplenia syndrome who survived the first month of life were at greater risk of dying from sepsis than from their heart disease. It is recommended that prophylactic antibiotics be administered to children with congenital absence of the spleen, commencing at three months of age, to be continued indefinitely.