DTP vaccine and infant sudden death syndrome. Meta-analysis

BACKGROUND: At the beginning of 1994, five cases of sudden infant death syndrome after DTP immunization appeared in Spain. In order to study a causal relationship a meta-analysis of the different studies that assess this possibility has been conducted. METHODS: The selection criteria was epidemiological study, case-control or cohort, assessing risk of sudden infant death syndrome in immunized versus non-immunized infants or risk of sudden infant death syndrome in recently immunized infants versus immunized infants beyond 30 days. Pooled risk ratios were calculated from adjusted risk ratios, when available, of the different studies, by a meta-analysis according the method described by Greenland. RESULTS: One cohort and four case-control studies were selected. Pooled risk ratio for immunized versus non-immunized infants was 0.67 (95% CI = 0.60-0.75). When comparing risk of sudden death syndrome in up to 30 days immunized infants versus more than 30 days immunized infants, the pooled risk ratio was 1.00 (95% CI = 0.84-1.20). CONCLUSIONS: DTP-immunization does not seem to increase the risk of sudden infant death syndrome. The risk of sudden infant death syndrome is not greater in the first thirty days following immunization. These data indicate a lack of association between DTP immunization and sudden infant death syndrome.     

Enhanced antibody response in Venezuelan infants immunized with Haemophilus influenzae type b-tetanus toxoid conjugate vaccine

The safety and immunogenicity of primary immunization at 2, 4 and 6 months of age with Haemophilus influenzae type b capsular polysaccharide conjugated to tetanus toxoid (PRP-T; Act-HIB) were evaluated in infants in Valencia, Venezuela. In order better to assess reactions to PRP-T, subjects received their initial PRP-T vaccine a mean of 6.5 days after their initial diphtheria-tetanus-pertussis (DTP) vaccine. The PRP-T vaccine was well tolerated. Serum was obtained at ages 2 and 7 months (before the first and 1 month after the third PRP-T dose). Antibody responses were compared with those from Nashville infants who had received PRP-T and DTP simultaneously in a previous trial. The preimmunization titers in the Venezuelan and Nashville infants did not differ. The geometric mean postimmunization titer in the Venezuelan infants was 37.9 micrograms/ml, as compared with 3.63 micrograms/ml in the Nashville infants (P < 0.00001). Possible explanations for the exceptional antibody response of these Venezuelan infants to PRP-T include carrier priming caused by prior DTP immunization, synergy associated with the specific DTP vaccine used, preimmunization immunologic experience that differed from their United States counterparts and genetic differences that altered response to the vaccines. Further studies are proposed to evaluate these possibilities.     

A randomized, controlled trial of aminophylline in ventilatory weaning of premature infants

OBJECTIVES: To determine whether maximal inspiratory force predicts successful neonatal extubation, and whether aminophylline affects maximal inspiratory force or the success rate of extubation. DESIGN: Double-blind, prospective, randomized, placebo-controlled trial. SETTING: Tertiary level neonatal intensive care unit. PATIENTS: A total of 20 ventilated, preterm, newborn infants: birth weight < 2.5 kg; gestation < 35 wks. INTERVENTIONS: Intravenous aminophylline 4 mg/kg bolus followed by 2.5 mg/kg every 6 hrs x three doses, then 1.5 mg/kg every 6 hrs; or placebo. Drug administration began when infants were receiving an FIO2 of < 0.4 and were progressively weaning from assisted mechanical ventilation. A standardized weaning protocol was instituted, and patients were extubated when they were able to tolerate a mechanical ventilatory rate of < 5 cycles/min. MEASUREMENTS AND MAIN RESULTS: Occlusion pressures, including maximal inspiratory force, were measured before aminophylline and daily until endotracheal extubation. Arterial blood gases were measured every 3 hrs, and 24-hr cardiac and respiratory recordings were performed postextubation. Three of ten aminophylline-treated patients failed extubation compared with two of ten placebo infants (p = nonsignificant). Mean apnea frequency postextubation was 0.02/hr in the aminophylline group compared with 0.3/hr in the placebo group (p < .05). Aminophylline had no effect on successful extubation or on maximal inspiratory force. Maximal inspiratory force was not correlated with the success of extubation. Apnea frequency postextubation was significantly reduced by aminophylline. CONCLUSIONS: Aminophylline is an effective prophylaxis for postextubation apnea in the preterm infant but does not affect maximal inspiratory force or increase the success rate of extubation in this patient population.     

Multicenter randomized clinical trial of home uterine activity monitoring: pregnancy outcomes for all women randomized

OBJECTIVE: Our purpose was to evaluate the impact of home uterine activity monitoring on pregnancy outcomes among women at high risk for preterm labor and delivery. STUDY DESIGN: Women at high risk for preterm labor at three centers were randomly assigned to receive high-risk prenatal care alone (not monitored) or to receive the same care with twice-daily home uterine activity monitoring without increased nursing support (monitored). There were 339 women with singleton gestations randomized with caregivers blinded to group assignment. The two groups were medically and demographically similar at entry into the study. RESULTS: Women in the monitored group had prolonged pregnancy survival (p = 0.02) and were less likely to experience a preterm delivery (relative risk 0.59; p = 0.04). Infants born to monitored women with singleton gestations were less likely to be of low birth weight (< 2500 gm; relative risk 0.47, p = 0.003), and were less likely to be admitted to a neonatal intensive care unit (relative risk 0.5, p = 0.01). CONCLUSION: These data show, among women with singleton gestations at high risk for preterm delivery, that the use of home uterine activity monitoring alone, without additional intensive nursing care, results in improved pregnancy outcomes, including prolonged gestation, decreased risk for preterm delivery, larger-birth-weight infants, and a decreased need for neonatal intensive care.     

Manual and computer-aided space analysis: a comparative study

Separate injections of Haemophilus influenzae type b capsular polysaccharide-tetanus conjugate (PRP-T) vaccine and diphtheria-tetanus-pertussis (DTP) reconstitution of freeze-dried PRP-T vaccine with liquid DTP vaccine have been shown to be safe and immunogenic in infants. The present study was conducted to test the safety and immunogenicity of the liquid combination vaccine administered to young infants in the dual-chamber syringe. The study was a monocenter, open clinical trial of 3 month-old infants receiving PRP-T and DTP vaccines in the dual-chamber syringe reconstituted prior to injection. Healthy infants were immunized according to a 3, 4 and 5 months-of-age schedule. The vaccine was administered in a dual-chamber syringe, ready to use with two chambers. The proximal chamber contained freeze-dried PRP-T and the distal chamber contained liquid combination-vaccine DTP. The freeze-dried PRP-T vaccine was reconstituted with the liquid DTP vaccine in the same unidose dual-chamber syringe (0.5 mL) and was injected intramuscularly into the deltoid region. Blood sampling was performed prior to vaccination at 3 months of age and after the third vaccination at 6 months. The primary end-point was the serological response to PRP-T vaccine as expressed by the percentage of infants with an antibody titer greater than or equal to 1 microgram/mL. The reactogenicity was expressed as the percentage of reported local and systemic reactions. A total of 108 infants were included in the study and received the dual-chamber syringe vaccine. After the third injection, all the infants had a PRP antibody titer greater than or equal to 0.15 microgram/mL and 94.4% of infants had a PRP antibody titer greater than or equal to 1 microgram/mL; the pertussis agglutinin titers were over the threshold 40 and 80 in all infants and 98.1% were over the threshold 320. After the third injection, all the infants had diphtheria antibody titers greater than 0.1 IU/mL and 83.3% had titers greater than 1 IU/mL; all the infants had tetanus antibody titers greater than 0.1 IU/mL and 97.2% had results over 1 IU/mL. Thirty-seven infants (34.6%) had local reactions and 64.5% had systemic reactions. The dual-chamber syringe may reduce the cost of vaccine delivery, as well as the workload, and increase the vaccine acceptability and coverage rate of vaccines.     

Valproic acid in prophylactic treatment of migraine

AIM: To determine whether an oral tetravalent rotavirus vaccine (RV-TV) can be safely coadministered with a combined diphtheria-tetanus-pertussis-Haemophilus influenzae type b vaccine (DTP/Hib) and oral poliovirus vaccine (OPV) to healthy infants without interfering with the immune responses to any of the component antigens. METHODS: Two hundred sixty-seven infants ages 2 to 3 months were randomly assigned in a double blind fashion to receive three doses of either placebo or RV-TV, each containing 4 x 10(5) plaque-forming units, concurrently with DTP/ Hib (Tetramune) and OPV at approximately 2, 4 and 6 months of age. Infants were followed for 5 days after each dose for the occurrence of adverse events and subsequently until 3 to 6 weeks after the third dose of RV-TV or placebo. Immune responses were assessed by measuring the postvaccination serum antibody titers to each component of DTP/ Hib and OPV at 3 to 6 weeks after the third dose. RESULTS: The percentage of infants who attained protective antibody titers and the distribution of antibody titers against diphtheria toxoid, tetanus toxoid and H. influenzae type b were not statistically different between RV-TV and placebo recipients. The distribution of antibody titers against different antigens of Bordetella pertussis (agglutinins, pertussis toxoid, filamentous hemagglutinin, fimbriae antigens and the 69-kDa outer membrane protein) was compared and no significant differences were found. The percentage of infants with detectable neutralizing antibodies against the three serotypes of poliovirus and the distribution of antibody titers was not statistically different between RV-TV and placebo recipients. There were no clinically meaningful differences in postvaccination reactions between RV-TV and placebo recipients. CONCLUSIONS: Three doses of RV-TV can be safely coadministered with three doses of DTP/ Hib and OPV without diminishing an infant's serum antibody responses to each component of these vaccines. Therefore RV-TV can be given at the standard childhood visits at 2, 4 and 6 months of age.     

Prolonged exposure to a visual pattern may promote behavioral organization in preterm infants

The article reports a study documenting preterm infants' responses to visual patterns placed in their incubators in the neonatal intensive care unit (NICU) and the effects of long-term exposure to the patterns. In the first experiment, 20 preterm infants were exposed to a visual pattern in two conditions, stationary and rotating, during two successive exposure periods. Regardless of condition, the majority of infants looked longer at the visual display during the second exposure period and experienced decreased heart rates and quiet, alert states. In a second experiment, visual patterns placed in 9 preterm infants' incubators on transfer to the intermediate side of the NICU remained in the incubator until discharge. An additional 9 infants served as controls. Infants exposed to the visual patterns experienced fewer state changes and stronger visual skills than infants in incubators without visual displays. These findings, although tentative because of the relatively small sample sizes, suggest that visual patterns may promote behavioral organization and visual skills in preterm infants.     

Haemophilus influenzae type b-specific antibody in infants after maternal immunization

OBJECTIVE: To study the kinetics of Haemophilus influenzae type b (Hib)-specific antibody in infants born to mothers immunized with an Hib polysaccharide or one of two Hib conjugate vaccines. STUDY DESIGN: Serum antibody to the polyribosylribitol (PRP) moiety of Hib was measured by radioimmunoassay and enzyme-linked immunosorbent assay at birth and at 2 and 6 months of age in infants born to women immunized with Hib polysaccharide or conjugate vaccine (PRP-D and HbOC). A subset of infants > or = 6 months of age was immunized with Hib conjugate vaccine after licensure of this vaccine for infants. A comparison group of 18 infants born to unimmunized women received the same Hib conjugate vaccine on a similar schedule. RESULTS: Total PRP antibody concentrations were 1.50, 14.4 and 20.4 microg/ml in 2-month-old infants born to mothers immunized with polysaccharide, PRP-D and HbOC vaccines, respectively, and 2.54, 1.35 and 2.46 microg/ml in 6-month-old infants. Infants born to mothers immunized with polysaccharide vaccine had significantly less PRP antibody at 2 months of age but similar antibody concentrations at 6 months of age. Persistence or increases in total PRP antibody during 6 months were noted in 21 of 47 (44.6%) study infants. A subset of study and comparison infants was immunized with a mean of 2.6 doses of Hib vaccines between 6 months and 2 years of age, and all infants had total PRP antibody concentrations > or = 0.15 microg/ml. CONCLUSION: Conjugate Hib vaccines administered during the last trimester of pregnancy resulted in significantly higher PRP antibody titers in infants at birth and 2 months of age than did polysaccharide vaccine. A subset of infants born to immunized mothers was subsequently immunized with Hib conjugate vaccine and had antibody concentrations similar to those in infants born to nonimmunized women.     

Adverse reactions after diphtheria-tetanus booster in 10-year-old schoolchildren in relation to the type of vaccine given for the primary vaccination

This prospective open study investigated adverse reactions in 527 schoolchildren to a diphtheria-tetanus (DT) booster given within a national vaccination programme at 10 years of age. Evaluation was based on those whose immunization records showed that they had received either three doses of an adsorbed DT vaccine (n = 388) or a non-adsorbed DT-pertussis vaccine (DTP) (n = 69) for primary series vaccination. No differences in systemic reactions to the booster between the two groups were observed. Local reactions were significantly (p < 0.001) more common 1 day after vaccination in children who had received DT for primary series vaccination: redness, 73% compared with 23%; swelling, 56% versus 15%; and itching, 47% versus 21%. One and 2 weeks after the booster, itching was still more pronounced in the group who had received DT for primary series vaccination (p < 0.001 and 0.014, respectively). The study indicates that there was a real basis for the increase in spontaneous notifications of local side-effects to the school DT booster in Sweden. The most likely cause for the increase seems to be the aluminium adjuvant in the vaccine given for primary vaccination, a late and unexpected consequence of a change in the infant immunization programme.     

Chest wall motion in preterm infants using respiratory inductive plethysmography

Preterm infant tidal breathing may be different from that of healthy full-term infants because of various features of the premature thorax. The purpose of this project was to describe chest wall motion in the preterm infant (gestational age <37 weeks) and compare it with chest wall motion data in a group of healthy, full-term infants. We wanted to use an objective bedside method for assessment with minimal disruption to the infant. The study population consisted of 61 preterm human infants whose mean(+/-sD) postconceptional age at time of study was 35.3+/-2.1 weeks. During the study, the infants were quietly awake in a prone position. Preterm infants had initially been admitted to a level III neonatal intensive care unit for acute management and had been transferred to a step-down area, where they were in stable condition for study. Data were collected with a semiquantitatively calibrated, noninvasive respiratory inductive plethysmograph. Mean(+/-SD) phase angle was significantly greater in preterm infants than in full-term infants (60.6+/-39.8 degrees versus 12.5+/-5.0 degrees, respectively, p < or = 0.0001). The laboured breathing index was significantly greater in preterm infants than in full-term infants (1.35+/-0.35 versus 1.01+/-0.01, respectively, p = 0.001). The ribcage contribution to breathing did not differ significantly between preterm and full-term infants (25.5+/-17.7% versus 36.3+/-14.4%, respectively, p = 0.11). These results indicate a significant increase in the degree of ribcage and abdomen asynchrony in the preterm subjects compared to the full-term infants. Plethysmography provided a time-efficient and objective method of assessing chest wall motion in this fragile population.     

Meta-analysis of DRD3 gene and schizophrenia: ethnic heterogeneity and significant association in Caucasians

BACKGROUND: Children with asthma may be at increased risk for low immunization rates given that they have recurrent illnesses that often result in acute care visits to their pediatrician, visits to the emergency room, admissions to the hospital, and visits to subspecialists, where immunizations are not routinely administered. OBJECTIVES: To assess immunization rates for routine and influenza vaccines in children with asthma and assess factors that may contribute to delay. METHODS: We conducted a cross-sectional survey of 117 children aged 6 to 48 months with onset of asthma within the first 15 months of life. Subjects were recruited from an allergy and immunology clinic at an urban, tertiary care center. Those judged to have immunization delay did not have the required 4 DTP, 3 OPV, and 1 MMR vaccine by age 24 months (4:3:1 series). Receipt of influenza vaccine was determined for eligible children with moderate to severe asthma. RESULTS: Seventy-four (80%) children had up-to-date immunizations at age 24 months. Those with delay had fewer visits to a subspecialist than those who were up-to-date (1 versus 2 visits P = .010). Twenty-two (25%) of 87 eligible subjects received influenza vaccine. Recipients were more likely to have been hospitalized than nonrecipients (77% versus 49%, P = .022). CONCLUSIONS: Though the majority of young children with asthma were up-to-date for routine immunizations, only 25% of children with moderate to severe asthma received influenza vaccine. Greater efforts must be made by pediatricians and asthma subspecialists to ensure that children with moderate to severe asthma are immunized against influenza virus.     

Surgical management of 671 abdominal aortic aneurysms: a 13 year review from a single centre

BACKGROUND: We analyzed the role that nutrition and the insulin-like growth factors IGF-I and IGFBP-3 play on neonatal growth. METHODS: Full-term and preterm infants with 1 and 3 weeks of postnatal life (n = 54 and n = 33, respectively) were studied. Anthropmetric variables, daily intake of energy and nutrients, and serum levels of IGF-I and IGFBP-3 were measured. RESULTS: At the first week after birth, preterm infants had lower IGF-I levels than did those in the control group. At the third week of postnatal life, serum IGF-I and IGFBP-3 levels showed a significant increase. Preterm infants born before 33 gestational weeks showed lower IGF-I (p < 0.02) and IGFBP-3 (p < 0.02) levels than those born between 33 and 37 gestational weeks. Preterm infants fed with human milk supplemented with a formula showed higher serum IGF-I levels than those fed exclusively with a milk formula (mean +/- SEM 48.2 +/- 9.5 micrograms/L vs. 25.4 +/- 4.4 micrograms/L, p < 0.05). IGF-I and IGFBP-3 were correlated between themselves and with energy and protein intake. Multiple regression analysis confirmed that energy intake and serum IGFBP-3 levels were the most predictable variables with regard to IGF-I levels at neonatal period. CONCLUSIONS: These feedings suggest that IGF-I levels during the neonatal periods are influenced by the maturity stage of the newborn, energy intake, and the type of lactation.     

CpG DNA can induce strong Th1 humoral and cell-mediated immune responses against hepatitis B surface antigen in young mice

Successful neonatal immunization of humans has proven difficult. We have evaluated CpG-containing oligonucleotides as an adjuvant for immunization of young mice (1-14 days old) against hepatitis B virus surface antigen. The protein-alum-CpG formulation, like the DNA vaccine, produced seroconversion of the majority of mice immunized at 3 or 7 days of age, compared with 0-10% with the protein-alum or protein-CpG formulations. All animals, from neonates to adults, immunized with the protein-alum vaccine exhibited strong T helper (Th)2-like responses [predominantly IgG1, weak or absent cytotoxic T lymphocytes (CTL)]. Th2-type responses also were induced in young mice with protein-CpG (in 1-, 3-, and 7-day-old mice) and protein-alum-CpG (in 1- and 3-day-old mice) but immunization carried out at older ages gave mixed Th1/Th2 (Th0) responses. DNA vaccines gave Th0-like responses when administered at 1 and 7 days of age and Th1-like (predominantly IgG2a and CTL) responses with 14-day-old or adult mice. Surprisingly, the protein-alum-CpG formulation was better than the DNA vaccine for percentage of seroconversion, speed of appearance, and peak titer of the antibody response, as well as prevalence and strength of CTL. These findings may have important implications for immunization of human infants.     

Relation between neonatal pneumonia and maternal carriage of group B streptococci

Obstetrical and neonatal complications were studied among 143 urogenital carriers of group B streptococci (GBS) and their 144 infants and compared with complications occurring in a control group of 157 pregnant non-carriers and their 158 infants. All parturients had experienced uncomplicated pregnancies until week 36. 26 infants, 13 from each group, were transferred to the neonatal intensive care unit for treatment and observation within the first 7 days of life. Among these infants, 11/13 infants of GBS carriers contracted pneumonia and pulmonary adaptation syndrome, in contrast to 3/13 infants of non-carriers (p less than 0.05). The GBS carrier infants transferred to the neonatal intensive care unit had higher birth weights and higher gestational ages. Within the group of infants born to GBS carriers, those with pulmonary diseases evidenced abnormal fetal heart rate changes during labour in a higher rate than in the controls. Puerperal endometritis occurred with a significantly higher frequency among the GBS carriers (7/143) than among the non-carriers (0/157). Maternal carriage of GBS is a high risk factor for both the mother and her newborn, also after an otherwise uncomplicated pregnancy.     

Postoperative apnea in former preterm infants after inguinal herniorrhaphy. A combined analysis

BACKGROUND: Controversy exists as to the risk for postoperative apnea in former preterm infants. The conclusions of published studies are limited by the small number of patients. METHODS: The original data from eight prospective studies were subject to a combined analysis. Only patients having inguinal herniorrhaphy under general anesthesia were included; patients receiving caffeine, regional anesthesia, or undergoing other surgical procedures were excluded. A uniform definition for apnea was used for all patients. Eleven risk factors were examined: gestational age, postconceptual age, birth weight, history of respiratory distress syndrome, bronchopulmonary dysplasia, neonatal apnea, necrotizing enterocolitis, ongoing apnea, anemia, and use of opioids or nondepolarizing muscle relaxants. RESULTS: Two hundred fifty-five of 384 patients from eight studies at four institutions fulfilled study criteria. There was significant variation in apnea rates and the location of apnea (recovery room and postrecovery room) between institutions (P < 0.001). There was considerable variation in the duration and type of monitoring, definitions of apnea, and availability of historical information. The incidence of detected apnea was greater when continuous recording devices were used compared to standard impedance pneumography with alarms or nursing observations. Despite these limitations, it was determined that: (1) apnea was strongly and inversely related to both gestational age (P = 0.0005) and postconceptual age (P < 0.0001); (2) an associated risk factor was continuing apnea at home; (3) small-for-gestational-age infants seemed to be somewhat protected from apnea compared to appropriate- and large-for-gestational-age infants; (4) anemia was a significant risk factor, particularly for patients > 43 weeks' postconceptual age; (5) a relationship to apnea with history of necrotizing enterocolitis, neonatal apnea, respiratory distress syndrome, bronchopulmonary dysplasia, or operative use of opioids and/or muscle relaxants could not be demonstrated. CONCLUSIONS: The analysis suggests that, if it is assumed that the statistical models used are equally valid over the full range of ages considered and that the average rate of apnea reported across the studies analyzed is accurate and representative of actual rates in all institutions, the probability of apnea in nonanemic infants free of recovery-room apnea is not less than 5%, with 95% statistical confidence until postconceptual age was 48 weeks with gestational age 35 weeks. This risk is not less than 1%, with 95% statistical confidence, for that same subset of infants, until postconceptual age was 56 weeks with gestational age 32 weeks or postconceptual age was 54 weeks and gestational age 35 weeks. Older infants with apnea in the recovery room or anemia also should be admitted and monitored. The data do not allow prediction with confidence up to what age this precaution should continue to be taken for infants with anemia. The data were insufficient to allow recommendations regarding how long infants should be observed in recovery. There is additional uncertainty in the results due to the dramatically different rates of detected apnea in different institutions, which appear to be related to the use of different monitoring devices. Given the limitations of this combined analysis, each physician and institution must decide what is an acceptable risk for postoperative apnea.     

An analysis of neonatal morbidity and mortality in maternal (in utero) and neonatal transports at 24-34 weeks' gestation

Sophisticated neonatal transport has improved the safety of transporting preterm infants, but may not substitute for the benefits of in utero transport. To describe gestational age trends and assess differences in complications between maternal (in utero) and neonatal transports, we analyzed maternal and neonatal transports, over 3 years, to the only tertiary center in the region. Those who delivered between 24 and 34 weeks' gestation were included in the analysis. Gestational age trends for each complication are described, showing, in general, decreasing morbidity with gestational age in both groups. These trends were usually parallel, but not equal. A significantly greater mean neonatal intensive care unit (p = 0.003) and total length of stay (p = 0.006) as well as longer ventilator time (p = 0.01) and oxygen therapy exposure (p = 0.018) were noted in those transported neonatally. The incidence of respiratory distress syndrome (p < 0.001), bronchopulmonary dysplasia (p = 0.027), intraventricular hemorrhage (p = 0.041), intraventricular hemorrhage grades III and IV (p = 0.008), patent ductus arteriosus (p = 0.032), and mortality (p = 0.001) were all significantly greater among the neonatal transports. The differences were not significant for retinopathy of prematurity, hyperbilirubinemia, necrotizing enterocolitis, periventricular leukomalacia, and culture proven sepsis. Specialized neonatal transport and advanced neonatology techniques have not removed the significant advantage of decreased morbidity, mortality, and length of hospital intervention resulting from maternal (in utero) transport.     

Methodological issues in determining rates of childhood immunization in office practice. A study from pediatric research in office settings (PROS)

OBJECTIVE: To compare 3 methods for measuring pediatric office immunization rates. DESIGN: Retrospective and prospective cross-sectional surveys. PATIENTS: Children 2 and 3 years old from 15 pediatric practices in 11 states. METHODS: Immunization rates were determined for each practice using 3 methods. The Consecutive method used data from the practice's medical records of patients seen consecutively in the office; the Chart method used data from randomly selected practice medical records; and the Active method (reference standard) used a combination of medical record data with a telephone interview to collect additional immunization data and current patient status, using data only on current patients. Analyses were based on a mean of 57, 62, and 51 (Consecutive, Chart, and Active method, respectively) patients per practice. Patients were considered fully immunized if they had received 4 doses of DTP/DT vaccine, 3 doses of OPV/IPV, and 1 dose of MMR vaccine by their second birthday Comparisons were made using the paired t test. RESULTS: The mean immunization rate by method was Consecutive, 81.5% (range, 51%-97%); Chart, 71.6% (range, 42%-94%); and Active, 79.6% (range, 53%-96%). Within a given practice, the differences between methods varied considerably (0 to 28 percentage points). The mean difference from the reference standard Active method was 8 percentage points (P < .001) for the Chart method and -1.9 percentage points (P = .36) for the Consecutive method. The largest difference was between the Consecutive and Chart methods (mean difference, 9.9 percentage points; P = .003). Practitioners uniformly found the Consecutive method easiest to implement. CONCLUSIONS: Practice-specific immunization rates are one of the few objective measures of the quality of preventive pediatric care. Pediatric practices monitoring their immunization rates should consider using the Consecutive method, a simple, acceptable, and valid measure of practice immunization rate.     

Pertussis in Massachusetts, 1981-1991: incidence, serologic diagnosis, and vaccine effectiveness

Massachusetts provides diphtheria-tetanus toxoid-pertussis (DTP) vaccine, and since 1980 has monitored pertussis with a statewide diagnostic service. The incidence of bacteriologically confirmed pertussis was 104.5 per 100,000 person-years in 1-month-old infants and declined progressively thereafter. Infants < 6 months old experienced disproportionate morbidity: 44% of bacteriologically confirmed pertussis, 64% of hospitalizations, and 71% of hospital days. Most children with pertussis had received < 3 DTP doses during childhood, whereas 87% of adolescents with pertussis had received > or = 4 doses. Serodiagnosis by single serum anti-pertussis toxin antibody ELISA increased the incidence of confirmed pertussis in persons 11-19 years old from 3.0 to 12.9 per 100,000 and in persons > or = 20 years old from 0.16 to 0.56 per 100,000. Bacteriologic methods underestimate pertussis incidence, but a single serum anti-pertussis toxin antibody ELISA is a practical method for population-based diagnosis in adolescents and adults.     

Developmental patterns of heart rate and variability in prematurely-born infants with apnea of prematurity

At equivalent post-conceptional ages, prematurely-born infants have higher heart rates and reduced heart rate variability, relative to full-term neonates. Premature birth might exert long-lasting effects on central and peripheral mechanisms that control cardiovascular activity. We assessed development of heart rate and heart rate variability in symptomatic preterm infants up to 6 months of age. Fifty 6.5-h evening recordings of EKG and breathing were obtained from prematurely-born infants (gestational ages: 24-35 weeks). Cardiac R-R intervals were captured with a resolution of +/- 0.5 msec. One-min epochs were selected from three periods of regular respiration in recordings from premature infants and 72 recordings of full-term infants at comparable post-conceptional ages. Mean heart rate and heart rate variability were determined for each recording. At 40 weeks post-conception, prematurely-born infants with apnea of prematurity showed higher heart rates and reduced heart rate variability than did full-term neonates. These differences between premature and full-term infants persisted throughout the next 6 months in those infants born prior to 30 weeks gestation, and in those infants born at 30-35 weeks who experienced respiratory distress syndrome (RDS) during the neonatal period. The findings suggest that premature delivery, or complications thereof, exerts long-lasting effects on cardiac control.     

Neonatal neutrophil activation is a function of labor length in preterm infants

To understand better the development of the neonatal immune system, we evaluated the role of labor length, gestational age, and mode of delivery on the expression of the neonatal neutrophil cell surface antigens CD11b, CD11c, CD15, CD33, and CD66b in premature newborns. Peripheral blood samples from 68 apparently healthy preterm infants were obtained within 12 h of birth and incubated with MAb to the CD antigens. Samples were lysed, fixed, and analyzed by flow cytometry. Multivariate analysis was used to study the simultaneous effect of the labor length and gestational age on the neonatal neutrophil cell surface antigen expression. A positive correlation was demonstrated between neutrophil antigen expression and labor length (p < 0.001-0.026) but not with the mode of delivery (p = 0.191-0.638). There was no significant correlation between expression of neutrophil antigens and gestational age at delivery (p = 0.057-0.866), except for CD15 (p = 0.010). Our results indicate labor length is a significant factor in neonatal neutrophil activation at birth. These findings are independent of gestational age in preterm newborns. Mode of delivery does not seem to influence neonatal neutrophil activation. The neutrophils of premature infants can be activated antenatally and/or during labor.