Detection of human immunodeficiency virus type 1 infection in young pediatric patients by using polymerase chain reaction and biotinylated probes.

Polymerase chain reaction (PCR) testing using up to four primer pairs and biotinylated probes was 97.9% sensitive (188 of 192 specimens positive) and 100% specific (267 of 267 specimens negative) for detecting the presence or absence of human immunodeficiency virus (HIV) DNA in peripheral blood mononuclear cells from pediatric patients whose HIV status has been confirmed. SK38/39 and SK145/150 were the most sensitive primer pairs, respectively detecting HIV DNA in 95.6 and 95.9% of peripheral blood mononuclear cell specimens from HIV-infected children and collectively detecting all adequately tested PCR-positive specimens. Primer pairs SK29/30 and SK68/69 respectively detected HIV DNA in only 76.4 and 76.6% of HIV-positive specimens. Among infants born to HIV-seropositive mothers, 30 who subsequently were confirmed to be infected were sampled when they were less than or equal to 6 months of age; in all but one infant, HIV DNA was found in the first specimen collected. Among the nine youngest infected infants tested, all were PCR positive by 38 days of age. PCR methods thus have reliably detected vertically transmitted HIV infection early in life.

Limitations in the laboratory diagnosis of vertically acquired HIV infection.

At present, the only well-standardized and widely available diagnostic techniques for HIV infection are detection of IgG HIV antibodies and HIV antigen. The antibody detection is sensitive, but is useful only in infants and children older than 15 months because of the presence of maternal antibodies. The utility of HIV antigen testing in neonates and young infants has not been established. A number of sensitive techniques, such as PCR, ELISPOT, and detection of HIV-specific IgM and IgA antibodies, are under development and promise to be very useful in the early diagnosis of vertical HIV infection. However, we will be able to accurately establish the sensitivity or specificity of the individual tests only when we have results of large prospective studies. These studies should compare different diagnostic methods and correlate the results of tests performed sequentially in neonates and young infants with the natural history of their disease process and eventual clinical outcome.

Refining DRGs. The example of children's diagnosis-related groups.

Congress exempted certain types of specialty hospitals from the Medicare Prospective Payment System because it was recognized that Diagnosis-Related Groups (DRGs) may not properly define the case mixes in such institutions. This study is part of a larger investigation into case mix and payment in children's hospitals, one category of exempted institutions. A national sample of approximately 500,000 cases was developed with intentional oversampling of children's and university hospitals to allow detection of specialized types of cases. Five case-mix classification schemes--DRGs, Disease Staging, Patient Management Categories, Severity of Illness Score, and Pediatric Diagnosis System groups--were applied to the data set, and data items not included in the Uniform Hospital Discharge Data Set were collected. A set of Children's Diagnosis-Related Groups (CDRGs), based on modification of the current DRG system, resulted from the study. When CDRGs were applied to an independent sample of children's hospital data, length of stay variance was reduced by 47.6% compared with 32.3% for DRGs (length of stay outliers removed). These results suggest that incremental approaches to DRG refinement in other clinical areas where current definitions are inadequate may be better than rejecting the large amounts of statistical and clinical analyses existing in the DRG system. Similar methods can be used to correct problems brought on by changes in medical practice.

Current approaches to the development of vaccines effective against parainfluenza and respiratory syncytial viruses.

Vaccines against parainfluenza (PIV) and respiratory syncytial viruses (RSV) that are currently being developed include both live and subunit vaccines. Candidate live PIV vaccines that have been found to be attenuated and efficacious in rodents or primate models are (1) cold-adapted, temperature-sensitive mutants of PIV-type 3 that have been serially passaged at low temperature (20 degrees C) in simian kidney tissue culture; (2) protease-activation mutants (PIV-1-Sendai), which have mutations that decrease the cleavability of their F glycoprotein by host cell protease; (3) an animal virus, bovine PIV-3 virus, which is antigenically related to the human PIV-3 virus, and (4) vaccinia recombinant viruses bearing RSV or PIV-3 glycoproteins. Subunit RSV and PIV-3 viruses are being produced and evaluated as immunogens. A major concern with these vaccines is the possibility of disease potentiation following virus infection as occurred previously with formalin-inactivated measles and RSV vaccines. Studies indicate that PIV-3 and RSV glycoprotein vaccines are immunogenic and efficacious in animals but insufficient data exist to estimate their capacity to potentiate disease. However, since a cotton rat model is available to detect potentiated disease resulting from infection of cotton rats previously immunized with formalin-inactivated RSV vaccine, it is now possible to systematically evaluate new vaccines in experimental animals for disease potentiation before studies are initiated in humans. It is likely within the next several years that one or more of these PIV or RSV vaccines will be tested in humans for safety and immunogenicity.

Respiratory syncytial virus infections and intravenous gamma-globulins.

The respiratory syncytial virus (RSV) is a common cause of bronchiolitis and pneumonia in infants and young children. Throughout the world annual RSV epidemics result in numerous hospitalizations, substantial morbidity and some mortality. Until the recent introduction of ribavirin only supportive therapy has been available for treating these infections. The development of animal models of RSV infection and the observation that some lots of immunoglobulin prepared for intravenous administration contained substantial RSV-neutralization antibody titers, prompted a series of studies examining the safety and efficacy of immunoglobulin prepared for intravenous administration in the prophylaxis and treatment of RSV infections. This discussion will review our published, or soon to be published, studies on the use of Sandoglobulin for both immunoprophylaxis and immunotherapy of RSV infections in cotton rats. It will summarize studies utilizing both parenteral and topical (tracheal) Sandoglobulin therapy for RSV infections in owl monkeys. Finally the results of a small double blind trial of parenteral albumin or Sandoglobulin in the therapy of RSV bronchiolitis and/or pneumonia in hospitalized children will be reviewed. The data show that immunoprophylaxis and immunotherapy of RSV infections in laboratory animals was well-tolerated, was safe and induced highly significant reductions in RSV shedding from the lower respiratory tract. Further, immunotherapy of RSV infections in children was also well-tolerated, induced no short or long term evidence of toxicity or injury and caused significant improvements in oxygenation and reductions in RSV shed from the respiratory tract.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous immunoglobulin treatment of respiratory syncytial virus infections in infants and young children.

Respiratory syncytial virus (RSV)-infected cotton rats (Sigmadon hispidus) and owl monkeys (Aotus trivirgatus) showed significant reductions in RSV shedding from their respiratory tracts following parenteral therapy with human intravenous immunoglobulin (IVIG) containing high titers of RSV-neutralizing antibody. Because this therapy was well tolerated and appeared safe, a double-blind, placebo-controlled IVIG immunotherapy pilot study was performed on 35 hospitalized, RSV-infected infants and children. The treatment was well tolerated and resulted in significant reductions in nasal RSV shedding and in improvements in transcutaneous oximetry readings. However, the mean duration of hospitalization was not reduced by IVIG treatment. Followup to date has revealed no harmful effects resulting from immunotherapy of RSV infections. These studies appear to refute the hypothesis that passively acquired antibody may exacerbate RSV bronchiolitis or pneumonia in infants. Studies with larger numbers of seriously ill children will be required to determine if immunoglobulin G immunotherapy of RSV infections in infants is of clinical value.

Evaluation of a latex test for rotavirus detection.

A latex agglutination (LA) test (Slidex Rota-Kit; bioMérieux, Marcy-l'Etoile, France) was a rapid, easily used method for detecting rotavirus (RV) in pediatric fecal specimens. With 45 RV-positive and 50 RV-negative diarrhea specimens, the sensitivity of the LA test was 82%, and the specificity was 100%. Six other specimens produced indeterminate results. The frequency of positive LA tests appeared to be proportional to the concentration of virions in the stool.

Environmental exposure of primary care personnel to ribavirin aerosol when supervising treatment of infants with respiratory syncytial virus infections.

The potential exposure to ribavirin aerosol in the environment was assessed in nurses caring for infants and children with severe lower respiratory tract infections due to respiratory syncytial virus. Ribavirin aerosol was administered via a ventilator, oxygen tent, or oxygen hood. Participants worked directly with infants receiving ribavirin for 20.0 to 35.0 h over a 3-day period. No toxic or adverse effects of ribavirin aerosol were observed in any of the 19 nurses studied, and ribavirin was not detected in erythrocytes, plasma, or urine collected after the potential exposure period.

Ribavirin aerosol treatment of serious respiratory syncytial virus infection in infants.

Bronchiolitis is one of the most serious pulmonary infections commonly caused by respiratory syncytial virus (RSV). RSV disease occurs in yearly epidemics and is most severe in children 1 year of age or younger. Approximately 1 in 50 to 1 in 100 infants are hospitalized after their first infection, and mortality fluctuates between 0.5 and 5.0 per cent. Patients with underlying conditions such as congenital heart disease and bronchopulmonary dysplasia are at higher risk for morbidity and mortality. Methods for rapid diagnosis of RSV infection and the advent of specific therapy with aerosolized ribavirin have revolutionized the management of hospitalized patients with moderate to severe disease. A 3- to 5-day course of ribavirin plus supportive measures should be used in infants who prove to be infected by RSV and who are deteriorating on traditional supportive therapy, and/or who have underlying cardiac and/or pulmonary or immune defects.

Aerosolized ribavirin in the treatment of patients with respiratory syncytial virus disease.

Thirty children 1 to 33 months of age were enrolled in a study of aerosolized ribavirin therapy for respiratory syncytial virus lower respiratory tract illness. Twenty patients received ribavirin and 10 received placebo. There were no significant differences between the groups in chronologic or gestational age or in days of illness prior to admission. Among patients with pneumonia 17% of 6 placebo patients vs. 64% of 11 ribavirin patients had radiographic evidence that multiple lung lobes were affected (P = 0.06). Placebo patients received 42.5 to 94.7 hours (mean, 58.6) of aerosol therapy, whereas ribavirin patients received 36.3 to 95.6 hours (mean, 55.7). Seventy-seven percent of all study patients were discharged within 5 days of starting treatment. Severity of illness was evaluated daily using a scale of 0 (normal) to 4+ (most severe). Ribavirin patients initially had a mean severity score 0.5 higher than placebo patients. By Day 2, their rate of improvement was significantly greater than that of placebo patients (P = 0.001). By Day 5, 36% of ribavirin patients with rales showed improvement, whereas rales persisted in 100% of placebo patients. The rate of improvement of oxygen saturation from first to last day of treatment was statistically significant only for ribavirin patients (P = 0.02). On Day 3, 65% of ribavirin patients (13) vs. 50% (5) placebo patients shed 10(-0.5) 50% tissue culture infective dose virus per 0.2 ml of nasal wash. No side effects or toxicity were associated with aerosol therapy. A short course of ribavirin treatment (approximately 3 days) proved safe and beneficial.

Longitudinal study of rotavirus infection and gastroenteritis in families served by a pediatric medical practice: clinical and epidemiologic observations.

During 29 months of prospective longitudinal study of diarrhea in the home, human rotaviruses (HRVs) infected one or more members in 51% of 65 families, 35 of 126 children (28%) and 16 of 124 adults (13%). Within the 33 affected families, 57% of 62 children and 25% of 65 adults were infected. HRV gastroenteritis peaked at 40/100 person years at ages 12 to 23 months and decreased to 5 episodes/100 person years in adults. Among 25 children 0 through 36 months of age who had HRV infection, 88% were symptomatic. Of the 22 children with symptomatic HRV infection, 1 required hospitalization and 8 were seen by their physician for supportive care. HRVs were found in 12% of 216 stools obtained during gastrointestinal illness, but in only 0.2% of 1238 non-illness stools tested. HRV infections were noted as early as October and as late as April. Of 33 families who were studied for 2 seasons, at least 1 individual in each of 3 families experienced HRV infections in both years, but only one, an adult, shed virus and had symptoms in both seasons.

Dissociation between serum neutralizing and glycoprotein antibody responses of infants and children who received inactivated respiratory syncytial virus vaccine.

The serum antibody response of infants and children immunized with Formalin-inactivated respiratory syncytial virus (RSV) vaccine 20 years ago was determined by using an enzyme-linked immunosorbent assay specific for the RSV fusion (F) and large (G) glycoproteins and a neutralization assay. Twenty-one young infants (2 to 6 months of age) developed a high titer of antibodies to the F glycoprotein but had a poor response to the G glycoprotein. Fifteen older individuals (7 to 40 months of age) developed titers of F and G antibodies comparable to those in children who were infected with RSV. However, both immunized infants and children developed a lower level of neutralizing antibodies than did individuals of comparable age with natural RSV infections. Thus, the treatment of RSV with Formalin appears to have altered the epitopes of the F or G glycoproteins or both that stimulate neutralizing antibodies, with the result that the immune response consisted largely of "nonfunctional" (i.e., nonneutralizing) antibodies. Subsequent natural infection of the vaccinees with wild-type RSV resulted in enhanced pulmonary disease. Despite this potentiation of illness, the infected vaccinees developed relatively poor G, F, and neutralizing antibody responses. Any or all of three factors may have contributed to the enhancement of disease in the RSV-infected vaccinees. First, nonfunctional antibodies induced by the inactivated RSV vaccine may have participated in a pulmonary Arthus reaction during RSV infection. Second, the poor antibody response of infants to the G glycoprotein present in the Formalin-inactivated vaccine may have been inadequate to provide effective resistance to subsequent wild-type virus infection. Third, the relatively reduced neutralizing antibody response of the infant vaccinees to wild-type RSV infection may have contributed to their enhanced disease by delaying the clearance of virus from their lungs.

Simultaneous infections with different enteric and respiratory tract viruses.

Infants and young children with rotavirus (RV) or visualized adenovirus in their stools were tested for the simultaneous presence of a respiratory viral pathogen in their upper respiratory tract. Overall, at least 10.7% of 484 study subjects had such dual infections, including 8.3% of 385 RV-positive gastroenteritis patients and 24.3% of 37 RV-positive respiratory disease patients. Respiratory syncytial virus was present in 34.1% of 41 dual infections with RV and at least 40% of the 12 to 15 dual infections with visualized fecal adenovirus. Other pathogens found in the respiratory tract of patients with RV or visualized fecal adenovirus infections included influenza viruses, adenoviruses, parainfluenza viruses, rhinoviruses, and a cytomegalovirus.

Fecal adenoviruses from a longitudinal study of families in metropolitan Washington, D.C.: laboratory, clinical, and epidemiologic observations.

During a 29-month period, we studied enteric infection in 70 families from a pediatric practice in suburban Washington, D.C. Fecal adenoviruses were detected in stools of 18 patients by tissue culture and electron microscopic procedures. From 6 through 11 months of age, the incidence of fecal adenoviruses associated with enteritis was seven per 100, and of confirmed enteric adenoviruses (EAds), three per 100 individuals per year. All EAds belonged to subgenus G (type 41). All three patients with EAds had diarrhea; two had vomiting and one had fever, but none required hospitalization. Ten of the 15 patients with non-EAds were younger than 2 years, and 60% had diarrhea, 40% had vomiting, and 20% had fever. Combined gastrointestinal and respiratory symptoms occurred more often in those who shed non-EAds (three of 11) than in matched controls (two of 48, P = 0.04). An adenovirus was detected in approximately 6% of gastroenteritis episodes, and confirmed EAds were present in approximately 2% of episodes of gastroenteritis in children younger than 2 years of age. None of the contacts of patients with non-EAds shed such virus in their stools. None of nine family contacts of those with EAd appeared to shed adenovirus in stool. In contrast, rotavirus spread readily to exposed adults (25% of 65) and children (56% of 62) when a child in similar families had rotavirus infection.