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1.  Blood stream infection is associated with altered heptavalent pneumococcal conjugate vaccine immune responses in very low birth weight infants 
Objective
Sepsis in older children and adults modifies immune system function. We compared serotype-specific antibody responses to heptavalent pneumococcal conjugate vaccine (PCV7) in very low birth weight infants (<1500g,VLBW) with and without blood stream infection (BSI) during their birth hospitalization.
Patients and Methods
Retrospective analysis of prospectively collected data for the Neonatal Research Network study of PCV7 responses among VLBWs. Infants received PCV7 at 2, 4, and 6 months after birth with blood drawn 4–6 weeks after 3rd dose. Serotype antibodies were compared between infants with or without a history of BSI. Regression models were constructed with birth-weight groups and other confounding factors identified in the primary study.
Results
244 infants completed the vaccine series and had serum antibody available; 82 had BSI. After adjustment, BSI was not associated with reduced odds of serum antibody ≥0.35μg/mL.
Conclusions
BSI was not associated with reduced odds of WHO-defined protective PCV7 responses in VLBWs.
doi:10.1038/jp.2013.5
PMCID: PMC3722279  PMID: 23370608
VLBW; immune response; vaccine; sepsis; blood stream infection
2.  Immunogenicity of Trivalent Influenza Vaccine in Extremely-Low-Birth-Weight, Premature versus Term Infants 
Background
Influenza vaccine immunogenicity in premature infants is incompletely characterized.
Objective
To assess the immunogenicity of trivalent, inactivated influenza vaccine (TIV) in extremely low-birth-weight (ELBW, ≤1000 grams birth weight), premature (<30 weeks gestation) infants. We hypothesized that geometric mean titers (GMT) of influenza antibody would be lower in premature than in full-term (≥37 week) infants.
Design/Methods
In this prospective, multicenter study, former premature and full-term infants ages, 6–17 months, received 2 doses of TIV during the 2006–7 or 2007–8 influenza seasons. Sera were drawn before dose 1 and 4–6 weeks after dose 2. Antibody was measured by hemagglutination inhibition.
Results
Over two years, 41 premature and 42 full-term infants were enrolled; 36 and 33 of these infants, respectively, had post-vaccination titers available. Premature infants weighed less (mean 1.3 – 1.8 kg difference) at the time of immunization than full-term infants. Pre-vaccination titers did not differ between groups. Premature infants had higher post-vaccination antibody GMT than full-term infants to H1 (2006–7, 1:513 v. 1:91, P=0.03; 2007–8, 1:363 v. 1:189, P=0.02) and B/Victoria (2006–7, 1:51 v. 1:10, P=0.02). More premature than full-term infants had antibody titers ≥ 1:32 to B/Victoria (85% v. 60%, p=0.04) in 2007–8. Two (5%) premature and 8 (19%) full-term infants had adverse events, primarily fever, within 72 hours after vaccination. No child had medically-diagnosed influenza.
Conclusions
Former premature infants had antibody responses to two TIV doses greater than or equal to those of full-term children. Two TIV doses are immunogenic and well tolerated in ELBW, premature infants 6–17 months old.
doi:10.1097/INF.0b013e31820c1fdf
PMCID: PMC3090695  PMID: 21273938
Premature infant; very low birth weight infant; influenza vaccines; immunization; vaccines
4.  HEPTAVALENT PNEUMOCOCCAL CONJUGATE VACCINE IMMUNOGENICITY IN VERY-LOW-BIRTH-WEIGHT, PREMATURE INFANTS 
Background
The heptavalent pneumococcal-CRM197 conjugate vaccine (PCV-7) has been incompletely studied in very-low-birth-weight (VLBW, ≤1500 grams) infants.
Objective
To assess PCV-7 immunogenicity in VLBW, premature infants. We hypothesized that the frequency of post-vaccine antibody concentrations ≥0.15 µg/mL would vary directly with birth weight.
Methods
This was a multi-center observational study. Infants 401–1500 grams birth weight and <32 0/7 weeks gestation, stratified by birth weight, were enrolled from 9 NICHD Neonatal Research Network centers. Infants received PCV-7 at 2, 4 and 6 months after birth and had blood drawn 4–6 weeks following the third dose. Antibodies against the 7 vaccine serotypes were measured by enzyme-linked immunosorbent assay.
Results
Of 369 enrolled infants, 244 completed their primary vaccine series by 8 months and had serum obtained. Subjects were 27.8 ± 2.2 (mean ± standard deviation) weeks gestation and 1008 ± 282 grams birth weight. Twenty-six percent had bronchopulmonary dysplasia and 16% had received postnatal glucocorticoids. Infants 1001–1500 grams birth weight were more likely than those 401–1000 grams to achieve antibody concentrations ≥0.15 µg/mL against the least two immunogenic serotypes (6B: 96% v. 85%, P = 0.003 and 23F: 97% v. 88%, P = 0.009). In multiple logistic regression analysis, lower birth weight, postnatal glucocorticoid use, lower weight at blood draw and Caucasian race were each independently associated with antibody concentrations <0.35 µg/mL against serotypes 6B and/or 23F.
Conclusion
When compared with larger premature infants, infants weighing ≤1000 grams at birth have similar antibody responses to most, but not all, PCV-7 vaccine serotypes.
doi:10.1097/INF.0b013e3181d264a6
PMCID: PMC2949965  PMID: 20234331
Infant, premature; infant, very low birth weight; pneumococcal vaccines; immunization; vaccines
5.  Cytokines Associated with Bronchopulmonary Dysplasia or Death in Extremely Low Birth Weight Infants 
Pediatrics  2009;123(4):1132-1141.
Background
Inflammation mediated by cytokines may be important in the pathogenesis of bronchopulmonary dysplasia and the competing outcome of death in extremely low birth weight infants.
Objective
To develop multi-variable logistic regression models for the outcome of bronchopulmonary dysplasia and/or death at 36w post-menstrual age using clinical and cytokine data from the first 28 days.
Methods
1067 extremely low birth weight infants in the Neonatal Research Network of the National Institute of Child Health and Human Development had 25 cytokines measured from blood collected within 4 h of birth and on days 3, 7, 14, and 21. Stepwise regression using peak values of the 25 cytokines and 15 clinical variables identified variables associated with BPD/death. Multi-variable logistic regression was done for bronchopulmonary dysplasia/death using variables selected by stepwise regression. Similar analyses were also done using average cytokine values from days 0–21, days 0–3, and from days 14–21.
Results
Of 1062 infants with available data, 606 infants developed bronchopulmonary dysplasia or died. Combining results from all models, bronchopulmonary dysplasia/death was associated with higher concentrations of interleukins-1β, -6, -8, -10, and interferon-γ and lower concentrations of interleukin-17, RANTES, and tumor necrosis factor-β. Compared to models with only clinical variables, addition of cytokine data improved predictive ability by a statistically significant but clinically modest magnitude.
Conclusions
The overall pattern of cytokines suggests bronchopulmonary dysplasia/death may be associated with impairment in the transition from the innate immune response mediated by neutrophils to the adaptive immune response mediated by T-lymphocytes.
doi:10.1542/peds.2008-0526
PMCID: PMC2903210  PMID: 19336372
Logistic models; Infant; premature; Predictive value of tests
6.  Risk Factors for Umbilical Venous Catheter-Associated Thrombosis in Very Low Birth Weight Infants 
Pediatric blood & cancer  2009;52(1):75-79.
Background
Thrombosis in neonates is a rare but serious occurrence, usually associated with central catheterization. The objective of this study was to investigate the risk factors associated with catheter related thrombosis in very low birth weight (VLBW) infants.
Procedure
The present retrospective study was performed using data from a randomized trial of duration of umbilical venous catheters (UVC) placement among infants <1250 g birth weight. Twenty-two cases of UVC-associated thrombosis were identified in this sample. The remaining study sample (n=188) served as the comparison group. Data on thrombosis, platelets, gestational age, birth weight, hematocrit, serum sodium, maternal preeclampsia, blood group, infant of diabetic mother and demographic factors were collected using database and record review.
Results
Among the total subjects (n=210), 112 (53%) were males and 126 (60%) were Caucasians, with mean gestational age of 27.7 ± 2.1 weeks (standard deviation) and mean birth weight of 923 ± 195 grams. Bivariate analysis revealed significant association of thrombosis with hematocrit >55% in the first week (odds ratio [OR] 5.4; 95% confidence interval [CI] 2.0-14.6; p=0.0003), being small for gestational age (OR, 2.9; 95% CI, 1.2-7.4; p=0.02) and maternal preeclampsia (OR, 3.97; 95% CI, 1.6-9.84; p=0.0017). In multivariate logistic regression analysis, only hematocrit >55% was independently associated with thrombus (OR, 3.7; 95% CI 1.1-11.8; p=0.03).
Conclusions
This study demonstrates a significant, independent association between elevated hematocrit and development of UVC-associated thrombosis. Careful monitoring for catheter-associated thrombosis may be indicated in VLBW infants who have hematocrit >55% in the first week of life.
doi:10.1002/pbc.21714
PMCID: PMC2585148  PMID: 18680150
neonate; thrombosis; risk factors; umbilical venous catheters

Results 1-6 (6)