Comparative detection of measles and rubella IgM and IgG derived from filter paper blood and serum samples.

We compared the use of serum and filter paper blood spots as specimen sources for the detection of measles- and rubella-specific IgM and IgG. We collected capillary blood into microtainer tubes and onto filter paper spots from 60 children and 60 healthy adults. The blood was collected from 12-15-month-old children approximately 3 weeks after primary vaccination with measles, mumps, rubella vaccine, and the sample-pairs were tested for measles-specific IgM and IgG antibodies by using a capture antibody EIA and an indirect EIA, respectively. We tested sample-pairs from a subset of participants for rubella- specific IgM and IgG antibodies by using commercially available capture IgM (Captia) and indirect IgG (Wampole) assays. The concordance of results from serum and filter paper blood spots was high for all assays: 98% for measles IgM, 93% for measles IgG, 94% for rubella IgM, and 93% for rubella IgG, and increased to between 96-100% for all four assays when indeterminate samples were excluded. The correlation coefficients for EIA signals were 0.99 and 0.77 for measles IgM and IgG, respectively, and 0.92 and 0.94 for rubella IgM and IgG, respectively. The cut-off values used for filter paper samples were the same as those used for serum samples for all tests except for the rubella IgM assay. The use of filter paper blood spots is a promising future option for the detection of measles- and rubella-specific antibodies.

Antibody responses of healthy infants to concurrent administration of a bivalent haemophilus influenzae type b-hepatitis B vaccine with diphtheria-tetanus-pertussis, polio and measles-mumps-rubella vaccines.

OBJECTIVE: To confirm that children given a bivalent Haemophilus influenzae type b-hepatitis B vaccine (bivalent Hib-HB vaccine; COMVAX) concurrently with priming doses of diphtheria-tetanus-pertussis vaccine (DTP), a booster dose of diphtheria-tetanus-acellular pertussis vaccine (DTaP), inactivated or oral polio vaccine (IPV or OPV) and measles-mumps-rubella vaccine (M-M-R(II)) have satisfactory antibody responses to all antigens. DESIGN: 126 healthy 2-month-old infants were scheduled to receive bivalent Hib-HB vaccine concurrently with DTP (2 and 4 months of age), OPV or IPV (random allocation to OPV or IPV at 2 months of age; OPV at 4 and 14 to 15 months of age), DTaP and M-M-R(II) (14 to 15 months of age). A response was judged "adequate" if the lower bound of the 95% confidence interval on the proportion of vaccinees having a critical antibody level was <10 percentage points below prediction. RESULTS: Antibodies to hepatitis B virus surface antigen, H. influenzae polysaccharide, diphtheria toxin, tetanus toxin, pertussis agglutinogens, pertussis toxin (as measured by enzyme immunoassay but not by Chinese hamster ovary cell assay), pertussis filamentous haemagglutinin after a booster dose of DTaP, poliovirus type 2, measles virus, and mumps virus all equalled or exceeded expected levels. Antibodies to rubella virus and pertussis filamentous haemagglutinin (after priming doses of DTP) fell slightly, and in the case of rubella significantly, below predicted levels. Antibodies to poliovirus types 1 and 3 were also below expectation after 2 doses of polio vaccine but were adequate following a third dose of vaccine. CONCLUSION: Concurrent administration of bivalent Hib-HB vaccine with priming doses of DTP, a booster dose of DTaP, OPV, IPV, or M-M-R(II) was well tolerated and, with the possible exception of rubella, did not substantially impair the antibody response to any antigen.

Safety and immunogenicity of four doses of Neisseria meningitidis group C vaccine conjugated to CRM197 in United States infants.

BACKGROUND: Following widespread use of conjugate pneumococcal vaccine, Neisseria meningitidis likely will become the leading cause of bacterial sepsis and meningitis in US children. This report describes the safety and immunogenicity in US children of four consecutive doses of a meningococcal group C vaccine conjugated to CRM197 via reductive amination (MnCC). METHODS: One hundred six healthy 2-month-old infants received MnCC at 2, 4 and 6 months of age in a randomized, controlled double blind study; children in the other treatment arm were given a 7-valent conjugate pneumococcal vaccine. Parents reenrolled 64 of these children at 12 to 15 months to receive a fourth dose of MnCC. Routine childhood vaccines, including DTP, were coadministered. Temperatures and symptoms were recorded for 3 days after each immunization. Serum enzyme-linked immunosorbent assay IgG and bactericidal antibodies were measured prevaccination and before and 1 month after Doses 3 and 4. RESULTS: Moderate to severe local reactions, defined as erythema or induration > or =2.4 cm or pain that interfered with limb movement was reported after 0 to 3.2% of MnCC injections, depending on the reaction and dose. Fever occurred in 23 to 37% of children, but the contribution of MnCC to the febrile reactions is unknown. Geometric mean concentrations of IgG antibody to group C meningococcal polysaccharide were 3.72 microg/ml after Dose 3 and 8.03 microg/ml after the booster. Geometric mean functional serum bactericidal antibody titers after Doses 3 and 4 were 1:463 and 1:2341, respectively. One hundred percent of children had a serum bactericidal antibody titer of > or =1:64 after three doses and > or = 1:128 after the booster. CONCLUSIONS: The MnCC vaccine had an acceptable safety profile and generated high titers of bactericidal antibody in immunized US infants and toddlers. It appears to be an attractive candidate vaccine for the prevention of serogroup C meningococcal disease in young children.

The Internet: a practical example of the use of new technology in the assessment of vancomycin use in pediatrics. The Pediatric Prevention Network.

BACKGROUND: The rapid emergence of both new infections and new technologies has revolutionized health care during the past 50 years. Increased use of the Internet has enabled health care professionals to educate, interact, and collaborate throughout the world in ways never before possible. Increased use of vancomycin has been associated with the emergence of organisms with decreased susceptibility to vancomycin, such as Enterococcus and staphylococcal species. The purpose of this article is to describe our experience using Internet technology to assess vancomycin use at children's hospitals in the United States. METHODS: A Web-based evaluation was developed and distributed on the Internet to 57 Pediatric Prevention Network hospitals. The evaluation was structured to collect summary statistics on vancomycin use and admissions data by service for 1997 and 1998. RESULTS: Twenty-four hospitals were able to provide archived vancomycin use and patient admissions data; completed evaluations were returned from 15 hospitals (62.5% response rate). Personnel at 6 (40%) hospitals completed the evaluation directly on the Internet. CONCLUSIONS: In our study, Internet technology facilitated a more efficient evaluation of vancomycin use, but fewer than half of the personnel at Pediatric Prevention Network hospitals completed the evaluation directly on the Internet. It is unclear whether personnel at these hospitals were limited in Internet access, support, or understanding. Efforts should be directed to educate health care personnel on the advantages of the Internet. Furthermore, many of the pharmacy databases used in our assessment were not standardized across hospitals nor systematically validated. Understanding that limitations still remain-within the source of the data studied, the health care system sampled, and the Internet tools available-is essential because the Internet offers health care professionals today a tool both to protect patients and to improve quality throughout the world.

Vancomycin use in pediatric hematology-oncology patients.

Across-sectional study was performed of pediatric hematology-oncology patients who received vancomycin; use was compared to the Centers for Disease Control and Prevention (CDC) recommendations for vancomycin use. Thirty-seven patients received 308 doses of vancomycin. AR patients initially received vancomycin as empirical therapy; 100% of this use was not consistent with the CDC recommendations.

Vancomycin use in pediatric neurosurgery patients.

OBJECTIVE: The objective of this article is to describe a pediatric neurosurgery patient population receiving vancomycin and examine the indications for and appropriateness of vancomycin use. METHODS: A cross-sectional study was performed on the pediatric neurosurgery patients at Egleston Children's Hospital who received vancomycin from January 1 through December 31, 1996. Vancomycin use was compared with the Centers for Disease Control and Prevention Hospital Infection Control Practices Advisory Committee recommendations for vancomycin use. RESULTS: Thirty patients received 115 doses of vancomycin. The median patient age was 8.0 years, and 17 (56.7%) were male. Vancomycin was used for prophylaxis in 28 (93.3%) patients and empiric therapy in 3 (10.0%) patients; one patient received vancomycin for surgical prophylaxis followed by empiric therapy for suspected meningitis. Vancomycin prophylaxis was initiated after the incision in 6 (21.4%) patients and was continued as prophylaxis for more than one dose in 26 (92.9%) patients. CONCLUSIONS: Vancomycin was used primarily as surgical prophylaxis in pediatric neurosurgery patients, and use was not consistent with the Hospital Infection Control Practices Advisory Committee recommendations. These data suggest that for certain subpopulations, such as pediatric neurosurgery patients, there is a need for more specialized recommendations. Furthermore, prudent vancomycin use is warranted to successfully decrease the risk of further emergence of vancomycin resistance. Because vancomycin use may be prevalent in this population, assessment of vancomycin use in pediatric neurosurgery patients followed by establishment of vancomycin clinical guidelines may help improve the appropriateness of vancomycin use in this population.

Decline of measles-specific immunoglobulin M antibodies after primary measles, mumps, and rubella vaccination.

Detection of measles-specific immunoglobulin M (IgM) has become the standard diagnostic method for laboratory confirmation of measles. In outbreaks, the interpretation of an IgM-positive result can be complicated when persons with suspected measles receive a dose of measles vaccine as part of outbreak control measures. This investigation evaluated the decay of measles-specific IgM antibodies 1 to 4 months after primary vaccination with measles, mumps, and rubella vaccine (MMRII). Serum samples were obtained from 536 infants vaccinated when they were 15 months old as part of a study to assess primary and secondary measles vaccine failure. Sixty serum specimens per week were selected from specimens collected between 4 and 9 weeks after MMRII vaccination; all 176 available serum specimens collected between 10 and > or = 16 weeks were included. Specimens were tested for the presence of measles-specific IgM by an antibody-capture enzyme immunoassay. The proportion of IgM-positive specimens dropped from 73% at 4 weeks after vaccination to 52% at 5 weeks after vaccination and then declined to 7% by 8 weeks after vaccination. Less than 10% of children remained IgM positive between 9 and 11 weeks. An IgM-negative result helps rule out the diagnosis of measles in a person with suspected infection and a history of recent vaccination. The interpretation of a positive IgM result from a person with a clinically suspected case of measles and a recent history of measles vaccination (especially within 8 weeks) is problematic, and the diagnosis of measles should be based on epidemiologic linkage to a confirmed case or on detection of wild-type measles virus.

Safety and immunogenicity of heptavalent pneumococcal vaccine conjugated to CRM197 in United States infants.

OBJECTIVE: To determine the safety and immunogenicity of heptavalent pneumococcal saccharide vaccine (serotypes 4, 6B, 9V, 14, 18C, 19F, 23F) individually conjugated to CRM197 (PNCRM7), administered at 2, 4, 6, and 12 to 15 months of age. DESIGN: Two hundred twelve healthy 2-month-old infants were equally randomized to receive four consecutive doses of PNCRM7 or an investigational meningococcal group C conjugate vaccine, which served as a control. Concomitantly administered routine vaccines were oral polio vaccine and combined diphtheria toxoid, tetanus toxoid, and whole cell pertussis vaccine/Haemophilus influenzae type b vaccine consisting of capsular oligosaccharides conjugated to CRM197 (DTP/HbOC) at 2, 4, and 6 months, and either measles-mumps-rubella vaccine or HbOC at 12 to 15 months. Active safety surveillance was conducted for 3 days after each dose. Antibody concentrations to each of the 7 pneumococcal serotypes were measured by enzyme-linked immunosorbent assay prevaccination, after doses two and three, prebooster, and postbooster. RESULTS: Significantly fewer children experienced local reactions at the PNCRM7 injection site than at the DTP/HbOC site. There was no increase in the incidence or severity of local reactions at the PNCRM7 site with increasing doses of vaccine. Mild to moderate postvaccination fever was common in both the PNCRM7 and control vaccine groups, however DTP/HbOC was administered concurrently. All 7 vaccine serotypes were immunogenic. The kinetics of the immune responses were serotype-specific. After three doses of PNCRM7, between 92% to 100% of children had >/=0.15 microg/mL of antibody, and 51% to 90% achieved a level of >/=1 microg/mL against specific serotypes. A booster dose of PNCRM7 resulted in a brisk anamnestic response to all 7 vaccine serotypes, demonstrating effective stimulation of T-cell memory by the primary series of vaccinations. CONCLUSION: Primary immunization followed by a booster dose of PNCRM7 seemed to be acceptably safe and resulted in significant rises in antibody to all 7 serotypes. Implications. Studies to assess vaccine efficacy of PNCRM7 for prevention of systemic disease, nasopharyngeal colonization, and acute otitis media are in progress. If PNCRM7 proves to be protective, there is the potential to prevent up to 85% of invasive pneumococcal disease occurring in US children.

Standardization of an opsonophagocytic assay for the measurement of functional antibody activity against Streptococcus pneumoniae using differentiated HL-60 cells.

Host protection against pneumococcal disease i primarily mediated by phagocytosis. We developed and standardized an opsonophagocytic assay using HL-60 cells (human promyelocytic leukemia cells). Fifty-five serum samples were analyzed for the presence of functional antibody against seven pneumococcal serogroups or serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F) by using differentiated HL-60 cells (granulocytes) and peripheral blood leukocytes (PBLs). Six of the 55 serum samples were from unvaccinated adult volunteers, 31 serum samples were from adults who received one dose of the 14-valent or the 23-valent polysaccharide vaccine, and 18 serum samples were from 16-month-old infants who received four doses of an investigational 7-valent polysaccharide-protein conjugate vaccine. The results of an opsonophagocytic assay with HL-60 cells correlated highly with those of an assay with PBLs as effector cells (median r for seven serotypes = 0.87: P < 0.01). Opsonophagocytic titers were compared with the immunoglobulin G antibody concentrations determined by enzyme-linked immunosorbent assay (ELISA). The r values for serogroups or serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F were 0.61, 0.60, 0.67 0.90, 0.61, 0.39, and 0.57, respectively, when HL-60 cells were used as effector cells and 0.56, 0.47, 0.61, 0.90, 0.71, 0.31, and 0.62, respectively, when PBLs were used. The assay requires small amounts of serum (40 microliters per serotype), making this test suitable for assaying infant sera. Culturable cells aid in assay standardization and likely reduce donor-to-donor variability. This standardized assay, in combination with the standardized ELISA, can be used to evaluate current and developing pneumococcal vaccines, in which functional opsonophagocytic antibody activity may correlate with protection against pneumococcal disease.

A comparative trial of standard or high-dose S subunit recombinant hepatitis B vaccine versus a vaccine containing S subunit, pre-S1, and pre-S2 particles for revaccination of healthy adult nonresponders.

The efficacy of 10-microg and 40-microg hepatitis B vaccines was compared with that of an investigational vaccine containing pre-S1, pre-S2, and S subunit particles (mixed particle vaccine) in inducing protective anti-hepatitis B surface antigen (anti-HBs) concentrations in 46 otherwise healthy persons who previously did not develop measurable levels of antibodies to at least one complete course of vaccine. A statistically significant difference was seen in the percentage of subjects who developed protective levels of anti-HBs (> or = 10 mIU/mL) with three 40-microg doses of S subunit vaccine versus the other groups. One hundred percent of the 40-microg dose group developed protective anti-HBs titers. No difference in adverse effects was noted.

Other viral agents of perinatal importance. Varicella, parvovirus, respiratory syncytial virus, and enterovirus.

This article summarizes new information on the natural history of maternal varicella and maternal parvovirus B19. Controversies in the therapy of respiratory syncytial virus are presented. Prophylactic and therapeutic immunotherapy of neonatal enteroviral disease are reviewed.

Vitamin A therapy for children with respiratory syncytial virus infection: a multicenter trial in the United States.

BACKGROUND: High dose vitamin A therapy is effective in reducing morbidity and mortality associated with measles infection. Children with acute respiratory syncytial virus (RSV) infection have low serum vitamin A concentrations. METHODS: We performed a multicenter, randomized, placebo-controlled trial of high dose vitamin A therapy among 239 children 1 month to 6 years of age to determine whether high dose vitamin A therapy would reduce morbidity associated with RSV infection. RESULTS: There were no differences between the vitamin A and placebo recipients for most clinical outcomes; however, vitamin A recipients had-longer hospital stays than placebo recipients (5.0 days vs. 4.4 days, P = 0.01) after enrollment. This effect was significant for children who were older than 1 year (who also had received the highest doses of vitamin A), particularly among those at low risk for complications of RSV infection and those enrolled during the second study season. Serum retinol levels at enrollment were inversely correlated with severity of illness. CONCLUSIONS: We found no evidence of a beneficial effect of vitamin A for the treatment of RSV infection in children in the United States. There may be groups of children for which vitamin A has an adverse effect, resulting in longer hospital stays.

Bacteremia in a pediatric hemodialysis unit secondary to Enterococcus fecalis.

UNLABELLED: Bacteremia is often a serious and recurring problem in children with hemodialysis catheters. We report an outbreak of Enterococcus bacteremia in a pediatric hemodialysis unit occurring from June 1992 to June 1993. During this period, 18 episodes of bacteremia occurred in eight children; 11 infections were polymicrobial. Enterococcus fecalis was associated with 13 infections in five patients (8 polymicrobial). Other pathogens included Enterobacter cloacae (5 infections), Staphylococcus (3), Staphylococcus epidermidis (2), and Klebsiella pneumoniae (2). All Enterococcus infections occurred in patients with dual-lumen subclavian venous catheters. Skin and catheter sites were culture negative, except in one patient. Rectal swabs were positive for Enterococcus in five patients. Enterococcus was not isolated from any source within the unit. Serotypes of all Enterococcus isolates were different, except for 2 isolates in the same patient. Starting in June 1993, catheters were flushed after dialysis with vancomycin or ampicillin. Since initiating this procedure, further episodes of Enterococcus bacteremia have not occurred. A questionnaire sent to other pediatric hemodialysis units failed to identify Enterococcus among 26 cases of bacteremia. IN CONCLUSION: (1) Enterococcus is an unusual pathogen for hemodialysis-related bacteremia in children; (2) patients with dialysis catheters were predisposed to this infection; (3) a common source for Enterococcus could not be identified by either culture or by serotyping; (4) flushing catheters with antibiotics after dialysis was effective prevention.

Neonatal enterovirus infection: virology, serology, and effects of intravenous immune globulin.

A prospective study of the virology of and serological responses to enterovirus infection in 16 neonates (< or = 2 weeks of life) and their mothers was performed. At study entry, 11 neonates did not have detectable serum neutralizing antibody to their own viral isolates, despite the presence of neutralizing antibody in 9 of 11 mothers of these infants. Viremia and viruria were demonstrated in 8 and 7 neonates, respectively, with maximal detected titers of 6.3 x 10(3) 50% tissue culture infective dose per mL (TCID50) and 6.8 x 10(1) TCID50/mL, respectively. Viremia was associated with onset of illness in the first 5 days of life, low initial serum neutralization titer, and the presence of echovirus serotypes. Randomized administration of intravenous immune globulin (IVIG; 750 mg/kg) to nine neonates overall modestly increased serum neutralization titers but did not reduce the daily incidence of viremia and viruria compared with that of controls. However, receipt of IVIG containing a neutralization titer of > or = 1:800 to the patients' own viral isolates was associated with significantly higher serum neutralization titers and more rapid cessation of viremia and viruria. Future trials of IVIG for neonatal enterovirus disease should assess the efficacy and safety of higher or repeated doses of this agent and/or of IVIG selected for their high titers to frequently circulating and/or particularly virulent enterovirus serotypes.

Cytokine response to respiratory syncytial virus stimulation of human peripheral blood mononuclear cells.

A key impediment to developing respiratory syncytial virus (RSV) vaccines is a lack of understanding of enhanced disease that occurred in children who received a formalin-inactivated RSV (FI-RSV) vaccine. Studies in mice have suggested that the FI-RSV vaccine induces a TH2 and live RSV induces a TH1 memory T cell response. In this study, the cytokine mRNA response of peripheral blood mononuclear cells (PBMC) from adults and children with and without previous RSV infection was characterized using a semiquantitative polymerase chain reaction (PCR). PBMC from 22 subjects previously infected with RSV usually had RSV-specific increases in TH1 cytokine-specific mRNA (interferon-gamma [IFN-gamma] mRNA, 20; interleukin [IL]-2 mRNA, 12; IL-5 mRNA, 6; and IL-4 mRNA, 0). PBMC from RSV antibody-negative children had no RSV-specific increases in IFN-gamma, IL-2, or IL-4 mRNA; 1 of 7 had an increase in IL-5 mRNA. These data indicate that naturally acquired RSV induces a TH1 memory T cell response.

Antibody responses of healthy infants to a recombinant hepatitis B vaccine administered at two, four, and twelve or fifteen months of age.

Hepatitis B vaccine was administered to healthy infants on two investigational schedules that fall within ranges recommended by the U.S. Public Health Service Advisory Committee on Immunization Practices and by the American Academy of Pediatrics Committee on Infectious Diseases. A month after receiving vaccine at 2, 4, and 12 or 15 months of age, 98% and 100% of the children had > 10 mIU antibodies to hepatitis B surface antigen per milliliter, with gemometric mean titers of 1358 mIU/ml and 3424 mIU/mL, respectively.

Immunogenicity of Haemophilus influenzae type b polysaccharide-tetanus toxoid conjugate vaccine in infants.

OBJECTIVE: To compare the safety and immunogenicity of three investigational lots of Haemophilus influenzae type b polysaccharide-tetanus toxoid (PRP-T) conjugate vaccine in infants. DESIGN: A multicenter, randomized immunogenicity trial. Infants were vaccinated at 2, 4, and 6 months of age with one of three lots of PRP-T. A control group received H influenzae type b oligomers conjugated to CRM197 (HbOC). Serum was obtained before each injection and 1 month after the third dose, and assayed blindly for antibody in one laboratory. SUBJECTS: Four hundred eighty-four infants from private pediatric practices located in five geographic areas. MEASUREMENTS AND RESULTS: There were no significant differences in the number of adverse events reported for infants receiving PRP-T or HbOC, and the rates did not exceed those observed previously in infants given diphtheria-tetanus-pertussis vaccine alone. Total serum anti-PRP antibody responses were analyzed in 336 infants who met strict inclusion criteria. After one, two, or three doses, the respective antibody responses to each of the three lots of PRP-T and to HbOC vaccine were similar. The only exception was one lot of PRP-T, which after one or two injections elicited significantly higher geometric mean antibody responses than the other two lots or the HbOC vaccine. After a third injection, there were no significant lot differences. Combining the data from the different lots, there were no significant differences in the geometric mean antibody concentration after three doses of PRP-T or HbOC (8.3 vs 7.7 micrograms/mL), and 95% and 91%, respectively, of infants had greater than 1.0 microgram/mL of antibody. There were no significant differences in the magnitudes of the respective IgG1-, IgG2-, and IgM-specific antibody concentrations between infants given PRP-T or HbOC. CONCLUSIONS: The three investigational lots of PRP-T tested were safe and were as immunogenic as or more so than the licensed HbOC conjugate vaccine.

Immunoglobulin class and subclass-specific monoclonal antibody sandwich ELISA for the detection of antibodies against coxsackieviruses B, types 1-5.

Immunoglobulin subclass-specific ELISAs were developed for human IgG1, IgG2, IgG3, IgG4, IgAtotal, and IgM directed against Coxsackie B (CB) virus types 1, 2, 3, 4, and 5. In all the assays the solid phase was coated with immunoglobulin class/subclass-specific monoclonal antibodies, followed by an incubation with the serum specimens. Incubation with one of the CB viruses, as well as an incubation with biotinylated serotype-specific monoclonal antibodies to the same virus type provided the virus specificity. Finally, there were incubations with peroxidase labeled Extravidin and the substrate-chromogen system. This ELISA method eliminated the competition between the immunoglobulin classes and subclasses. IgG3 and/or IgG1 were seen most frequently of the IgG subclasses, but IgG2 and IgG4 were also present infrequently. The viral specificity of the antibody subclass assays seems to be predominantly at the enterovirus group level, but this remains to be evaluated in a larger study. IgA and IgM were seen almost exclusively in specimens from patients with acute enteroviral infections, except in the assays with the crude CB5 antigen. This indicates the possible suitability of the IgA and IgM assays as diagnostic tests for enteroviral infections. A larger study is necessary to confirm this finding.