Expected infant seropositivity rates reached 80% vs 55% following second- vs third-trimester immunization (modified odds ratio, 3.7 [95% CI, 2.1C6.5], .001). ESR120G, Virion-Serion) settings. graduate studies]; 0 if unfamiliar) as explained elsewhere . Neonatal characteristics included birth excess weight KRAS2 and height, sex, and health status. Definition of Expected Infant Seropositivity The antibody concentration required for seroprotection against pertussis is definitely unknown. Given the postulated essential part of anti-PT antibodies against severe infant pertussis , we centered our cutoff for expected infant seropositivity within the published anti-PT Cetaben half-life (36 days) in adults , which was confirmed in babies of mothers immunized during pregnancy [12, 27, 28]. We determined that birth anti-PT concentrations 30 EU/mL would be associated with seropositivity (antibody persistence 5 EU/mL) until at least 3 months of age and defined expected infant seropositivity accordingly. In the absence of related data for anti-FHA antibodies, results were only indicated as GMCs and their 95% confidence interval (CI). Sample Size and Statistical Analyses The sample size was determined to show noninferiority, having a margin of 10%, in expected infant seropositivity rates among ladies immunized in the second vs the third trimester. Postulating that 90% of term neonates created to ladies immunized in the third trimester would be seropositive up to 3 months and presuming balanced organizations, a 1-sided risk of 2.5%, and a power of 90%, we initially calculated a necessary sample size of 210 women per group. This sample size exceeded the number of patients required to display noninferiority in the anti-PT GMC percentage (133 ladies per group, presuming a third-trimester GMC equal to 17.3 ). Ultimately, however, the paucity of ladies immunized in the second trimester led Cetaben to a final inclusion of 122 women in this group. Given uncertainties on the required minimal sample size and the wish to avoid introducing potential pertussis exposure bias, recruitment was eventually terminated on 30 May 2015. A 95% CI of the GMC percentage above Cetaben 0.67 determined GMC noninferiority in the second trimester group. Similarly, noninferiority Cetaben was reached if the 2-sided 95% CI round the difference in expected infant seropositivity rates (second minus third trimester) was entirely above ?10%, or equivalently if the 2-sided 95% CI around the odds ratio (OR) was entirely above 0.44. Descriptive analyses were performed to identify potential differences between the 2 study organizations Cetaben using the MannCWhitney, College student value .05 was considered statistically significant. Stata software version 13 (StataCorp) was utilized for all statistical analyses. RESULTS Study Population Ultimately, we enrolled 335 pregnant women immunized with Tdap and delivering term newborns between 15 July 2014 and 30 May 2015 (Supplementary Number 1); 213 of 335 (64%) were immunized during the third trimester and 122 of 335 (36%) during the second. At baseline, the 2 2 organizations differed significantly only with regard to parity and 2 SES scores (Table ?(Table11). Table 1. Baseline Characteristics of Ladies and Newborns Valueatest (normal distribution) or MannCWhitney test for assessment between means; 2 test or Fisher precise test for comparisons between proportions. Distinct denominators among SES variables reflect missing data in 3 subcategories. * .05 and ** .001. Anti-PT and Anti-FHA Antibody Concentrations Birth anti-PT GMCs in wire blood were significantly higher following second- vs third-trimester immunization (57.1 EU/mL [95% CI, 47.8C68.2] vs 31.1 EU/mL [95% CI, 25.7C37.7], respectively; .001) and anti-FHA (284.4 EU/mL [95% CI, 241.3C335.2] vs 140.2.
Expected infant seropositivity rates reached 80% vs 55% following second- vs third-trimester immunization (modified odds ratio, 3