Effectiveness of Maternal Immunization With Boostrix at Preventing Pertussis Among Infants <2 Months Old in the United States

Effectiveness of Maternal Immunization With Boostrix at Preventing Pertussis Among Infants <2 Months Old in the United States: Analysis of a Dataset From a Case-control Study

The purpose of this study is to estimate the effectiveness of maternal immunization with Boostrix at preventing pertussis in infants in the United States.

Study Overview

• Status: Completed
• Conditions: Whooping Cough
• Intervention / Treatment: Other: Not applicable / dataset analysis

• Study Type: Observational
• Enrollment (Actual): 290

Contacts and Locations

Study Locations

• Belgium
  • Wavre, Belgium, 1300
    • GSK Investigational Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 2 days to 2 months (Child)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Infant subjects, born to mothers exposed, or unexposed to Boostrix or any Tdap vaccination, coming from 6 emerging program network sites.

Description

Inclusion Criteria:

Inclusion criteria for case infants:

• Case infants were eligible for the enrolment if they:
• were at least 2 days old and < 2 months old on the cough onset date
• resided in the catchment area on their cough onset date
• were born in a hospital in their state of residence
• were ≥37 weeks' gestational age at birth
• were neither adopted nor in foster care
• did not live in a residential care facility

Inclusion criteria for control infants:

• Control infants were eligible for the enrolment if they:
• were at least 2 days old and <2 months old on the case infant's cough onset date
• were born in a hospital in their state of residence
• were ≥37 weeks' gestational age at birth
• were neither adopted nor in foster care
• did not live in a residential care facility
• were born at the same hospital as the case infant

did not have pertussis diagnosis prior to the cough onset date of the corresponding case infant

Exclusion Criteria:

• Infants (case and controls) whose mothers have received Adacel or mothers without brand information available, as well as controls who were matched to a case whose mother received Adacel or mothers without brand information available, will be excluded from the analysis of the effectiveness of vaccination with Boostrix.

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Control
• Time Perspectives: Retrospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Pertussis Case Group; Infant subjects of at least 2 days old and less than (<) 2 months old, who met the pertussis diagnosis definition (laboratory confirmed pertussis, epidemiological linkage to a laboratory-confirmed case, clinically compatible illness), and who met the case infants inclusion criteria (resided in the catchment area on their cough onset date, were born in a hospital in their state of residence, had at least 37 weeks gestational age at birth, were neither adopted, nor in foster care and did not live in a residential care facility). This post-hoc analysis was limited to cases and controls whose mothers were either vaccinated with Boostrix or did not receive any Tdap vaccine. Cases with no remaining matched control were also excluded from the analysis and vice versa.	Other: Not applicable / dataset analysis; Not applicable / dataset analysis
Control Group; Infant subjects of at least 2 days old and less than (<) 2 months old, who did not have a pertussis diagnosis prior to the cough onset date and who met the inclusion criteria for control infants (were born on a hospital in their state of residence, were at least 37 weeks gestational age at birth, were neither adopted, nor in foster care, did not live in a residential care facility, were born at the same hospital as the case infant). This post-hoc analysis was limited to cases and controls whose mothers were either vaccinated with Boostrix or did not receive any Tdap vaccine. Cases with no remaining matched control were also excluded from the analysis and vice versa.	Other: Not applicable / dataset analysis; Not applicable / dataset analysis

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Pertussis Cases and Matched Controls Among Infants Born to Mothers Vaccinated With Boostrix Vaccine (During Third Trimester of Pregnancy) or Not Exposed to Any Tdap Vaccine During Pregnancy	Vaccine effectiveness at preventing pertussis occurrence in infants < 2 months old is assessed by comparing the Boostrix immunization status during the third pregnancy trimester in mothers of infant pertussis cases and matched controls. The association between maternal Boostrix vaccination and pertussis in infants was analyzed using conditional logistic regression. The multivariate analysis was performed to obtain the adjusted values. Covariates that were statistically significant in the univariate analysis or considered as clinically significant were included in the multivariable conditional logistic regression model. Subjects with missing or unknown values, if any, for at least one of the risk factors were excluded from the model.	During the data collection period (from 1 January 2011 to 31 December 2014)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Pertussis Cases and Matched Controls Among Infants Born to Mothers Vaccinated With Boostrix Vaccine (Before Pregnancy, During First or Second Trimester, After Pregnancy) or Not Exposed to Any Tdap Vaccine During Pregnancy	Vaccine effectiveness at preventing pertussis occurrence in infants < 2 months old is assessed by comparing the Boostrix immunization status before pregnancy, during first or second pregnancy trimester, after pregnancy in mothers of infant pertussis cases and matched controls. The association between maternal Boostrix vaccination and pertussis in infants was analyzed using conditional logistic regression. The multivariate analysis was performed to obtain the adjusted values. Covariates that were statistically significant in the univariate analysis or considered as clinically significant were included in the multivariable conditional logistic regression model. Subjects with missing or unknown values, if any, for at least one of the risk factors were excluded from the model.	During the data collection period (from 1 January 2011 to 31 December 2014)
Number of Pertussis Cases and Matched Controls Among Infants Born to Mothers Vaccinated With Boostrix Vaccine (During First, Second or Third Trimester) or Not Exposed to Any Tdap Vaccine During Pregnancy	Vaccine effectiveness at preventing pertussis occurrence in infants < 2 months old is assessed by comparing the Boostrix immunization status during pregnancy in mothers of infant pertussis cases and matched controls. The association between maternal Boostrix vaccination and pertussis in infants was analyzed using conditional logistic regression. The multivariate analysis was performed to obtain the adjusted values. Covariates that were statistically significant in the univariate analysis or considered as clinically significant were included in the multivariable conditional logistic regression model. Subjects with missing or unknown values, if any, for at least one of the risk factors were excluded from the model.	During the data collection period (from 1 January 2011 to 31 December 2014)
Number of Pertussis Cases Leading to Hospitalization and Matched Controls in Infants Born to Mothers Vaccinated With Boostrix (Before Pregnancy, During First or Second, Third Trimester, After Pregnancy) or Not Exposed to Any Tdap Vaccine During Pregnancy	Vaccine effectiveness at preventing pertussis occurrence leading to hospitalization in infants < 2 months old is assessed by comparing the Boostrix immunization status before pregnancy, during first or second, third trimester, after pregnancy in mothers of infant pertussis cases and matched controls. The association between maternal Boostrix vaccination and pertussis in infants was analyzed using conditional logistic regression. The multivariate analysis was performed to obtain the adjusted values. Covariates that were statistically significant in the univariate analysis or considered as clinically significant were included in the multivariable conditional logistic regression model. Subjects with missing or unknown values, if any, for at least one of the risk factors were excluded from the model.	During the data collection period (from 1 January 2011 to 31 December 2014)

Collaborators and Investigators

• Sponsor: GlaxoSmithKline

Publications and helpful links

General Publications

• Skoff TH, Blain AE, Watt J, Scherzinger K, McMahon M, Zansky SM, Kudish K, Cieslak PR, Lewis M, Shang N, Martin SW. Impact of the US Maternal Tetanus, Diphtheria, and Acellular Pertussis Vaccination Program on Preventing Pertussis in Infants <2 Months of Age: A Case-Control Evaluation. Clin Infect Dis. 2017 Nov 29;65(12):1977-1983. doi: 10.1093/cid/cix724.

Study record dates

Study Major Dates

• Study Start (Actual): February 15, 2019
• Primary Completion (Actual): May 15, 2019
• Study Completion (Actual): May 15, 2019

Study Registration Dates

• First Submitted: February 13, 2019
• First Submitted That Met QC Criteria: June 3, 2019
• First Posted (Actual): June 4, 2019

Study Record Updates

• Last Update Posted (Actual): July 7, 2020
• Last Update Submitted That Met QC Criteria: July 3, 2020
• Last Verified: July 1, 2020

More Information

Terms related to this study

• Keywords: effectiveness; pregnancy; infants; Tdap; Boostrix; Whooping Cough
• Additional Relevant MeSH Terms: Infections; Respiratory Tract Infections; Respiratory Tract Diseases; Bordetella Infections; Gram-Negative Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Whooping Cough
• Other Study ID Numbers: 210031

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No