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Biomedical subjects

M D Decker

Publications and source records attributed to M D Decker.

At least 73 records · Page 4Linked to original sources

Differences in antibody response to whole-cell pertussis vaccines.

It has been assumed that whole-cell pertussis vaccines (WCVs) commercially distributed in the United States are of comparable immunogenicity, as all must comply with established standards for licensure. However, we have recently noted significant differences in antibody responses between groups of infants receiving the two WCVs commercially available in the United States. In separate studies performed concurrently under similar protocols at Vanderbilt and Johns Hopkins universities, infants were randomized to receive either an acellular pertussis vaccine or WCV. The acellular pertussis vaccine used at the two sites was identical, but the WCVs were from different manufacturers. Antibody responses to acellular pertussis vaccine did not differ between the two studies; responses to WCV differed dramatically, with infants receiving the Lederle WCV producing a 46-fold increase in antibody to pertussis toxin, compared with a 2.4-fold increase for infants receiving the Connaught WCV (P = .00003). Evaluation of other comparative data sets that were available provided further support for the conclusion that the two commercially available WCVs consistently differed in their ability to induce antibody to pertussis toxin. These findings have important implications for the design and interpretation of clinical trials comparing acellular and WCV products.

Adhesins, Bacterial↗

Natural history of pertussis antibody in the infant and effect on vaccine response.

To better characterize the transplacental transfer and persistence of pertussis antibodies and their role in the immune response to vaccine, concentrations of pertussis agglutinins and antibodies to lymphocytosis promoting factor (LPF) and filamentous hemagglutinin (FHA) were measured in three distinct groups of serum. Transplacental pertussis IgG antibody concentrations in newborns were found to be comparable to corresponding maternal concentrations and to decline with a half-life of approximately 6 weeks. By the age of 4 months, most infants had no detectable antibodies to LPF or FHA. Higher concentrations of maternally derived antibody to LPF were associated with a significantly weaker antibody response to conventional vaccine. In contrast, acellular vaccine stimulated superior antibody production, regardless of antecedent concentrations of antibody to LPF. The data support continuation of the current schedule of pertussis immunization and further efforts to develop an acellular vaccine for use in young infants.

Adult↗

Immunization of hospital personnel and other health care workers.

Hospital personnel and other health care workers are at increased risk of acquiring certain communicable diseases that can be prevented by immunization. These include hepatitis B, influenza, rubella, measles, and mumps, among others. The use of vaccines to protect health care workers as well as certain barriers to institutional immunization programs is discussed.

Hepatitis B Vaccines↗

Immunization after invasive Haemophilus influenzae type b disease. Serologic response to a conjugate vaccine.

Fifteen children with previous invasive Haemophilus influenzae type b disease were immunized with a Hemophilus-diphtheria toxin mutant protein conjugate vaccine. Serologic responses were compared with those of 31 newly immunized children without previous invasive H influenzae type b disease. Mean levels of antibody to polyribosylribitol phosphate among study children younger than 18 months were 0.086 mg/L before immunization, 0.737 mg/L after first immunization, and 4.453 mg/L after second immunization. In contrast, the comparable mean polyribosylribitol phosphate antibody levels among control children younger than 18 months were 0.107, 3.580, and 63.502 mg/L. A similar pattern of results was found among children aged 18 months or older. Although children with previous invasive H influenzae type b disease do not respond as vigorously to conjugate vaccine as do previously healthy controls, the response is sufficient to justify routine immunization of such children.

Age Factors↗

Evaluation of a new highly purified pertussis vaccine in infants and children.

Purified acellular pertussis vaccine (12.5 micrograms of lymphocytosis promoting factor [LPF] and 12.5 micrograms of filamentous hemagglutinin [FHA]) was compared with conventional pertussis vaccine in a randomized double-blind study involving 40 children aged 4-6 y, 40 children aged 18-24 mo, and 50 infants. Increases in antibody were significantly greater among recipients of acellular vaccine than among recipients of conventional vaccine for antibodies to LPF in all age groups and for antibodies to FHA in infants and children aged 4-6 y; the increase in FHA antibody was also greater with acellular vaccine among children aged 18-24 mo but not significantly so. Compared with conventional vaccine, acellular vaccine was significantly associated with reduced frequency of leg pain and fretfulness at all ages and less frequent fever and anorexia at some ages. The reduced reaction rates and comparable or enhanced immunogenicity of the acellular vaccine make it an attractive candidate for larger field trials, particularly among infants.

Antibodies, Bacterial↗

Changing trends in infection control and hospital epidemiology.

From the staphylococcal era through the gram-negative era into the AIDS era, hospital infection control has evolved into a dynamic discipline whose horizons are broadening to include many of the challenges facing hospitals today.

Acquired Immunodeficiency Syndrome↗

Failure of hospitals to promote the use of child restraint devices.

Motor vehicle accidents are the leading cause of death in children. In 1977, Tennessee adopted the nation's first law requiring the use of child restraint devices (CRDs), but despite extensive promotional efforts, a majority of young children still travel unrestrained. We surveyed all acute-care hospitals in Tennessee to determine their policies regarding CRDs. Of 109 hospitals with obstetric services, 28 (26%) had a policy calling for discharged newborns to be transported in CRDs; only seven (5%) of 128 pediatric services had such a policy. It is time for hospitals and professional organizations to adopt policies to ensure that the parents of every child discharged from an obstetric or pediatric unit are educated concerning CRD use laws and are able to comply with them. Pediatricians should consider incorporating "discharge in child restraint device" into their routine discharge orders.

Accidents, Traffic↗

Central venous catheter infections.

When used wisely, central venous catheters are capable of providing vital circulatory access in any patient with a remarkably low risk of infection or major complication. Tunneled silicone catheters are the route of choice for long-term or outpatient use, particularly for oncology or TPN patients; insertion of such a catheter should occur early in the hospitalization of a newly diagnosed patient on chemotherapy. The greatest experience has accrued with the cuffed silicone catheters (for example, Broviac), but the totally implantable devices (for instance, Port-a-cath) may become the device of choice in pediatric outpatients. For infants, small, percutaneously inserted noncuffed silicone catheters appear to offer the greatest safety. Among acute care patients, percutaneous plastic central venous catheters fulfill a vital role but represent an important source of infection. Scrupulous technique, the minimizing of manipulation, and a readiness to replace the catheter at any suggestion of trouble are important to achieving the best results. Within a given design, it is generally best to use the smallest diameter catheter capable of performing the desired tasks. However, on the basis of currently available data, there need be no hesitation to use a multilumen catheter if the care of the patient demands multiple access ports. The various silicone catheters can usually be left in place while infection is treated, although fungal and certain other infections are more likely to require catheter removal. Percutaneous plastic catheters should be removed or changed over a wire if infection is suspected; if tip culture of the removed catheter is positive, and the catheter was replaced over a wire, then the replacement catheter should be promptly removed.

Bacterial Infections↗

Description of case-mix adjusters by the Severity of Illness Working Group of the Society of Hospital Epidemiologists of America (SHEA).

Hospitals, insurance companies, and federal and state governments are increasingly concerned about reducing patient cost expenditures while maintaining high quality patient care. One method of reducing expenditures has been to tie hospital reimbursement with a prospective payment system based on diagnosis-related groups (DRGs). However, reimbursement under the DRG system is not acceptable for all patients in all hospitals because it is neither an accurate predictor of costs nor of clinical outcome. This deficiency poses significant problems for hospitals because DRGs are used nationwide as the prospective payment system for inpatients covered by Medicare. Several case-mix adjusters have been proposed to modify DRGs to improve their accuracy in predicting costs and outcome. We reviewed five of the most widely available indices: Acute Physiologic and Chronic Health Evaluation (APACHE II), Coded Disease Staging, Computerized Severity Index (CSI), Medical Illness Severity Group System (MEDISGROUPS), and Patient Management Categories (PMC). Recommendations for the use of a single case-mix adjuster cannot be made at this time because all indices have not been compared in sufficiently diverse settings and because some are better predictors of costs while others are better predictors of clinical outcome. Hospital epidemiologists and other infection control practitioners should be informed about these indices and their potential applications as they expand their role beyond infection control problems to issues concerning cost containment, quality assurance, and reimbursement.

Cost Control↗

Lack of comparability between commonly used serological assays of immune response to Haemophilus influenzae vaccine.

Reliable measures of the serum level of antibody to the capsular polysaccharide (PRP) of Haemophilus influenzae type b (Hib) are essential for evaluating current and future vaccines intended to protect against invasive disease. It was recently noted, however, that certain commonly used assays of antibody to PRP produced incompatible results. To investigate this observation, we analyzed banked sera from four PRP vaccine studies in parallel by several assays. Significant differences were noted, both in absolute titers and in the ratios of post- to prevaccination titers, between the various assays. These differences seemed to be due to the different antigen preparations used in the assays. Unless workers standardize on a single assay, protective levels of antibody to PRP will have to be defined separately for each assay. Serological results of Hib vaccine trials cannot be compared without considering the assay methods used.

Antibodies, Bacterial↗

Eikenella corrodens.

Eikenella corrodens is a microaerophilic gram-negative rod which is a normal inhabitant of human mucosal surfaces, particularly the oral cavity. Although an uncommon cause of infection, it is by no means rare. It is found most often as part of a mixed infection, particularly with streptococci, but is capable of independently causing serious infection in both normal and immunocompromised hosts. Given its slow growth, requirement for hemin when grown aerobically, and preference for CO2 enrichment, it is likely that the involvement of Eikenella in an infection is not always recognized, and it would be prudent to alert the laboratory in situations where isolation of Eikenella is likely (especially in head and neck infections or infected wounds caused by a human bite). Although mixed infections which include Eikenella may resolve with treatment directed at the other infecting organisms, treatment of such infections with antibiotics to which Eikenella is resistant may result in a pure Eikenella infection. Such an outcome may occur, for example, when a human bite wound is treated with clindamycin or metronidazole. Among the oral antibiotics, penicillin, tetracycline, and chloramphenicol are generally effective, whereas cephalexin, dicloxacillin and their relatives are not. Cefoxitin and the third-generation cephalosporins are highly effective against Eikenella.

Anti-Bacterial Agents↗

Frequency of broviac catheter infections in pediatric oncology patients.

Indwelling, right atrial catheters are important in the care of children with cancer, despite the risk of infection. We have reviewed the records of 64 pediatric oncology patients with 70 Broviac catheters. Fifty infections (17 exit site, 25 septic, and 8 combined) occurred during 17,581 catheter-days, a crude rate of 2.8 infections/1,000 catheter-days. The risk of infection correlated most strongly with age; for example, only children aged one through four years had multiple infections. Overall, 70% of infections were cured without removing the catheter, including 83% of septic infections. However, as compared with newly inserted catheters, the subsequent mean infection-free interval was greatly reduced for catheters associated with a previous, cured infection. Thus, although most Broviac catheter infections can be cured without catheter removal, insertion of a new catheter may nonetheless be necessary in patients who may need prolonged intravenous therapy.

Adolescent↗