Dataset Information

Maternal Immunization Earlier in Pregnancy Maximizes Antibody Transfer and Expected Infant Seropositivity Against Pertussis.

ABSTRACT:

Background

Maternal immunization against pertussis is currently recommended after the 26th gestational week (GW). Data on the optimal timing of maternal immunization are inconsistent.

Methods

We conducted a prospective observational noninferiority study comparing the influence of second-trimester (GW 13-25) vs third-trimester (?GW 26) tetanus-diphtheria-acellular pertussis (Tdap) immunization in pregnant women who delivered at term. Geometric mean concentrations (GMCs) of cord blood antibodies to recombinant pertussis toxin (PT) and filamentous hemagglutinin (FHA) were assessed by enzyme-linked immunosorbent assay. The primary endpoint were GMCs and expected infant seropositivity rates, defined by birth anti-PT >30 enzyme-linked immunosorbent assay units (EU)/mL to confer seropositivity until 3 months of age.

Results

We included 335 women (mean age, 31.0 ± 5.1 years; mean gestational age, 39.3 ± 1.3 GW) previously immunized with Tdap in the second (n = 122) or third (n = 213) trimester. Anti-PT and anti-FHA GMCs were higher following second- vs third-trimester immunization (PT: 57.1 EU/mL [95% confidence interval {CI}, 47.8-68.2] vs 31.1 EU/mL [95% CI, 25.7-37.7], P < .001; FHA: 284.4 EU/mL [95% CI, 241.3-335.2] vs 140.2 EU/mL [95% CI, 115.3-170.3], P < .001). The adjusted GMC ratios after second- vs third-trimester immunization differed significantly (PT: 1.9 [95% CI, 1.4-2.5]; FHA: 2.2 [95% CI, 1.7-3.0], P < .001). Expected infant seropositivity rates reached 80% vs 55% following second- vs third-trimester immunization (adjusted odds ratio, 3.7 [95% CI, 2.1-6.5], P < .001).

Conclusions

Early second-trimester maternal Tdap immunization significantly increased neonatal antibodies. Recommending immunization from the second trimester onward would widen the immunization opportunity window and could improve seroprotection.

SUBMITTER: Eberhardt CS

PROVIDER: S-EPMC4787611 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature

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Publications

Maternal Immunization Earlier in Pregnancy Maximizes Antibody Transfer and Expected Infant Seropositivity Against Pertussis.

Eberhardt Christiane S CS Blanchard-Rohner Geraldine G Lemaître Barbara B Boukrid Meriem M Combescure Christophe C Othenin-Girard Véronique V Chilin Antonina A Petre Jean J de Tejada Begoña Martinez BM Siegrist Claire-Anne CA

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 20160120 7

<h4>Background</h4>Maternal immunization against pertussis is currently recommended after the 26th gestational week (GW). Data on the optimal timing of maternal immunization are inconsistent.<h4>Methods</h4>We conducted a prospective observational noninferiority study comparing the influence of second-trimester (GW 13-25) vs third-trimester (≥GW 26) tetanus-diphtheria-acellular pertussis (Tdap) immunization in pregnant women who delivered at term. Geometric mean concentrations (GMCs) of cord blo ...[more]

PMID: 26797213

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Project description:BackgroundThis paper compares cost-effectiveness results from two models of maternal immunization to prevent pertussis in infants in Brazil, one static, one dynamic, to explore when static models are adequate for public health decisions and when the extra effort required by dynamic models is worthwhile.MethodsWe defined two scenarios to explore key differences between static and dynamic models, herd immunity and time horizon. Scenario 1 evaluates the incremental cost/DALY of maternal acellular pertussis (aP) immunization as routine infant vaccination coverage ranges from low/moderate up to, and above, the threshold at which herd immunity begins to eliminate pertussis. Scenario 2 compares cost-effectiveness estimates over the models' different time horizons. Maternal vaccine prices of $9.55/dose (base case) and $1/dose were evaluated.ResultsThe dynamic model shows that maternal immunization could be cost-saving as well as life-saving at low levels of infant vaccination coverage. When infant coverage reaches the threshold range (90-95%), it is expensive: the dynamic model estimates that maternal immunization costs $2 million/DALY at infant coverage > 95% and maternal vaccine price of $9.55/dose; at $1/dose, cost/DALY is $200,000. By contrast, the static model estimates costs/DALY only modestly higher at high than at low infant coverage. When the models' estimates over their different time horizons are compared at infant coverage < 90-95%, their projections fall in the same range.ConclusionsStatic models may serve to explore an intervention's cost-effectiveness against infectious disease: the direction and principal drivers of change were the same in both models. When, however, an intervention too small to have significant herd immunity effects itself, such as maternal aP immunization, takes place against a background of vaccination in the rest of the population, a dynamic model is crucial to accurate estimates of cost-effectiveness. This finding is particularly important in the context of widely varying routine infant vaccination rates globally.Clinical trial registryClinical Trial registry name and registration number: Not applicable.

Project description:BackgroundImmunization with tetanus-diphtheria-acellular pertussis (Tdap) vaccine in pregnancy is increasingly recommended. We determined the effect of Tdap immunization in pregnancy on infants' vaccine responses.MethodsIndividual-participant data meta-analysis of ten studies (n=1884) investigating infants' antibody response to routine immunizations following Tdap immunization in pregnancy was performed. Geometric mean ratios (GMRs) of antigen-specific immunoglobulin G (IgG) levels were calculated using mixed-effects models. Seroprotection rates were compared using chi-squared tests.ResultsInfants of Tdap-immunized women had significantly lower IgG against pertussis toxin (GMR 0.65; 95%CI 0.57-0.74), filamentous haemagglutinin (FHA) (0.68; 0.53-0.87), pertactin (0.65; 0.58-0.72) and fimbria 2/3 (FIM2/3) (0.41; 0.32-0.52) after primary immunization, compared with infants of unimmunized women. These lower levels persisted after booster immunization for FHA (0.72; 0.61-0.84) and FIM2/3 (0.53; 0.29-0.96). After primary immunization, infants of Tdap-immunized women had lower seroprotection rates against diphtheria (90% [843/973] vs 98% [566/579]; p<0.001) and invasive pneumococcal disease (IPD) caused by 5 Streptococcus pneumoniae (SPN) serotypes (SPN5, SPN6B, SPN9V, SPN19A, SPN23F), and higher seroprotection rates against Haemophilus influenzae type b (short-term and long-term seroprotection rates, 86%[471/547] vs 76%[188/247] and 62%[337/547] vs 49%(121/247), respectively, all p=0.001). After booster immunization, seroprotection rates against diphtheria and tetanus were 99% (286/288) and (618/619) in infants of Tdap-immunized women, respectively.ConclusionsInfants of Tdap-immunized women in pregnancy had lower IgG levels against pertussis, diphtheria and some SPN serotypes after their immunization compared with infants of unimmunized women. Enhanced surveillance of pertussis, diphtheria and IPD in infants is needed to determine the clinical significance of these findings.Systematic review registrationCRD42017079171.

Project description:ImportanceInfants younger than 1 year have the highest burden of pertussis morbidity and mortality. In 2011, the US introduced tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccination during pregnancy to protect infants before vaccinations begin.ObjectiveTo assess the association of maternal Tdap vaccination during pregnancy with the incidence of pertussis among infants in the US.Design, setting, and participantsIn this ecologic study, a time-trend analysis was performed of infant pertussis cases reported through the National Notifiable Diseases Surveillance System between January 1, 2000, and December 31, 2019, in the US. Statistical analysis was performed from April 1, 2020, to October 31, 2022.ExposuresMaternal Tdap vaccination during pregnancy.Main outcomes and measuresPertussis incidence rates were calculated and compared between 2 periods-the pre-maternal Tdap vaccination period (2000-2010) and the post-maternal Tdap vaccination period (2012-2019)-for 2 age groups: infants younger than 2 months (target group of maternal vaccination) and infants aged 6 months to less than 12 months (comparison group). Incidence rate differences between the 2 age groups were modeled using weighted segmented linear regression. The slope difference between the 2 periods was estimated to assess the association of maternal Tdap vaccination with pertussis incidence among infants.ResultsA total of 57 460 pertussis cases were reported in infants younger than 1 year between 2000 and 2019; 19 322 cases (33.6%) were in infants younger than 2 months. During the pre-maternal Tdap vaccination period, annual pertussis incidence did not change among infants younger than 2 months (slope, 3.29 per 100 000 infants per year; P = .28) but increased slightly among infants aged 6 months to less than 12 months (slope, 2.10 per 100 000 infants per year; P = .01). There was no change in the difference in incidence between the 2 age groups (slope, 0.08 per 100 000 infants per year; P = .97) during the pre-maternal Tdap vaccination period overall. However, in the post-maternal Tdap vaccination period, incidence decreased among infants younger than 2 months (slope, -14.53 per 100 000 infants per year; P = .001) while remaining unchanged among infants aged 6 months to less than 12 months (slope, 1.42 per 100 000 infants per year; P = .29). The incidence rate difference between the 2 age groups significantly decreased during the post-maternal Tdap vaccination period (slope, -14.43 per 100 000 infants per year; P < .001). Pertussis incidence rate differences were significantly different between the pre-maternal and post-maternal Tdap vaccination periods (slope difference, -14.51 per 100 000 infants per year; P = .01).Conclusions and relevanceIn this study, following maternal Tdap vaccine introduction, a sustained decrease in pertussis incidence was observed among infants younger than 2 months, narrowing the incidence gap with infants aged 6 months to less than 12 months. These findings suggest that maternal Tdap vaccination is associated with a reduction in pertussis burden in the target age group (<2 months) and that further increases in coverage may be associated with additional reductions in infant disease.

Project description:BackgroundThis study aimed to assess whether Italian healthcare workers (HCWs) recommend the reduced antigen content tetanus-diphtheria-acellular pertussis vaccination (Tdap) to pregnant people, as well as what variables could predict their decision to advise and recommend immunization to pregnant people.MethodsThis cross-sectional study took place between August 2021 and June 2022 in a sample of obstetricians-gynecologists, midwives, and primary-care physicians in two regions of Southern Italy. A self-administered questionnaire was used to gather the data.ResultsThe results showed 91.3% (379) of participants knew that receiving the Tdap vaccine during pregnancy protects against pertussis in both the expectant person and the newborn before active immunization. Only 68.9% (286) knew that the Tdap vaccination has to be administered during the third trimester of gestation. A small but still significant proportion of participants (14.7%) (61) believed that the potential risks of vaccines administered during pregnancy outweighed the benefits. An improvable proportion of HCWs regularly provided information [71.8% (298)] and recommended [81% (336)] Tdap vaccination to pregnant people. The strongest factors that drove HCWs to inform pregnant people about the Tdap vaccination were to be aware that vaccinating those in close contact with newborns is an effective strategy to prevent pertussis (OR: 2.38; 95% CI: 1.11-5.13) and that the Tdap vaccine is provided only in the third trimester of pregnancy (OR: 1.74; 95% CI: 1.06-2.86). Informing pregnant people about the possibility of receiving the Tdap vaccine during pregnancy (OR: 60.13; 95% CI: 23.50-153.8) was the strongest predictor of having recommended the Tdap vaccination during pregnancy.ConclusionEducational and informative interventions to improve HCWs' knowledge about the importance of the Tdap vaccine and their communication skills to properly counsel pregnant people are needed. Beyond vaccine recommendations, how well immunization strategies are implemented in real-world situations impacts vaccination uptake. Therefore, during regular care visits, expecting people must have easy access to vaccines. Prenatal immunizations should become common practice, and there should be no conceptual doubt about vaccinations among HCWs to safeguard pregnant people and their unborn children from vaccine-preventable diseases.

Dataset Information

Maternal Immunization Earlier in Pregnancy Maximizes Antibody Transfer and Expected Infant Seropositivity Against Pertussis.

Background

Methods

Results

Conclusions

Publications

Maternal Immunization Earlier in Pregnancy Maximizes Antibody Transfer and Expected Infant Seropositivity Against Pertussis.

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