Whooping Cough
Conditions
Keywords
Whooping Cough, Boostrix, Tdap, effectiveness, pregnancy, infants
Brief summary
The purpose of this study is to estimate the effectiveness of maternal immunization with Boostrix at preventing pertussis in infants in the United States.
Interventions
Not applicable / dataset analysis
Sponsors
GlaxoSmithKline
Study design
Observational model
CASE_CONTROL
Time perspective
RETROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
2 Days to 2 Months
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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 | During the data collection period (from 1 January 2011 to 31 December 2014) | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| 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 | During the data collection period (from 1 January 2011 to 31 December 2014) | 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. |
| 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 | During the data collection period (from 1 January 2011 to 31 December 2014) | 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. |
| 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 | During the data collection period (from 1 January 2011 to 31 December 2014) | 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. |
Countries
Belgium
Participant flow
Recruitment details
The present analysis has been performed on the data set of a case-control study conducted in 6 US Emerging Infection Program Network states, either statewide (4 states) or in select counties (2 states) by Skoff et al., 2017.
Pre-assignment details
The primary study was a case-control study evaluating the effectiveness of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines (Boostrix and Adacel) administered during pregnancy in preventing pertussis in infants.
Participants by arm
| Arm | Count |
|---|---|
| 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. | 107 |
| 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. | 183 |
| Total | 290 |
Baseline characteristics
| Characteristic | Control Group | Total | Pertussis Case Group |
|---|---|---|---|
| Age, Continuous Infant's age (weeks) | 4.8 Weeks STANDARD_DEVIATION 2 | 4.9 Weeks STANDARD_DEVIATION 2 | 5.0 Weeks STANDARD_DEVIATION 1.9 |
| Race/Ethnicity, Customized Black | 13 Participants | 22 Participants | 9 Participants |
| Race/Ethnicity, Customized Other-unspecified | 30 Participants | 40 Participants | 10 Participants |
| Race/Ethnicity, Customized White | 140 Participants | 228 Participants | 88 Participants |
| Sex: Female, Male Female | 90 Participants | 139 Participants | 49 Participants |
| Sex: Female, Male Male | 93 Participants | 151 Participants | 58 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 0 | 0 / 0 |
| other Total, other adverse events | 0 / 0 | 0 / 0 |
| serious Total, serious adverse events | 0 / 0 | 0 / 0 |
Outcome results
Primary
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.
Time frame: During the data collection period (from 1 January 2011 to 31 December 2014)
Population: The analysis includes cases and at least one matched control born from mothers either unvaccinated or vaccinated with Boostrix. Subjects with missing or unknown values, if any, for at least one of the risk factors were excluded from the model.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Pertussis Case Group | 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 | Unvaccinated | 72 Participants |
| Pertussis Case Group | 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 | Vaccinated during third trimester | 5 Participants |
| Control Group | 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 | Unvaccinated | 112 Participants |
| Control Group | 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 | Vaccinated during third trimester | 17 Participants |
Comparison: To assess the effectiveness of maternal vaccination with Boostrix during third trimester of pregnancy (at least 14 days before delivery) at preventing pertussis in infants \<2 months95% CI: [-64.93, 92.68]
Secondary
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.
Time frame: During the data collection period (from 1 January 2011 to 31 December 2014)
Population: The analysis includes cases and at least one matched control born from mothers either unvaccinated or vaccinated with Boostrix. Subjects with missing or unknown values, if any, for at least one of the risk factors were excluded from the model.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Pertussis Case Group | 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 | Unvaccinated | 72 Participants |
| Pertussis Case Group | 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 | Vaccinated, before pregnancy | 1 Participants |
| Pertussis Case Group | 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 | Vaccinated, during first or second trimester | 1 Participants |
| Pertussis Case Group | 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 | Vaccinated, after pregnancy | 27 Participants |
| Control Group | 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 | Vaccinated, after pregnancy | 41 Participants |
| Control Group | 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 | Unvaccinated | 112 Participants |
| Control Group | 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 | Vaccinated, during first or second trimester | 6 Participants |
| Control Group | 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 | Vaccinated, before pregnancy | 4 Participants |
Comparison: To assess the effectiveness of maternal vaccination with Boostrix before pregnancy at preventing pertussis in infants \<2 months95% CI: [-1071.8, 97.13]
Comparison: To assess the effectiveness of maternal vaccination with Boostrix during first or second trimester of pregnancy at preventing pertussis in infants \<2 months95% CI: [-439.75, 97.35]
Comparison: To assess the effectiveness of maternal vaccination with Boostrix after pregnancy at preventing pertussis in infants \<2 months95% CI: [-166.37, 52.16]
Secondary
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.
Time frame: During the data collection period (from 1 January 2011 to 31 December 2014)
Population: The analysis includes cases and at least one matched control born from mothers either unvaccinated or vaccinated with Boostrix. Subjects with missing or unknown values, if any, for at least one of the risk factors were excluded from the model.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Pertussis Case Group | 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 | Vaccinated, during pregnancy (Any trimester) | 6 Participants |
| Pertussis Case Group | 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 | Unvaccinated | 72 Participants |
| Control Group | 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 | Vaccinated, during pregnancy (Any trimester) | 23 Participants |
| Control Group | 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 | Unvaccinated | 112 Participants |
Comparison: To assess the effectiveness of maternal vaccination with Boostrix at any time during pregnancy at preventing pertussis in infants \<2 months95% CI: [-57.51, 92.13]
Secondary
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.
Time frame: During the data collection period (from 1 January 2011 to 31 December 2014)
Population: The analysis includes cases leading to hospitalization and at least one matched control born from mothers either unvaccinated or vaccinated with Boostrix. Subjects with missing or unknown values, if any, for at least one of the risk factors were excluded from the model.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Pertussis Case Group | 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 | Vaccinated, before pregnancy | 1 Participants |
| Pertussis Case Group | 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 | Vaccinated, during third trimester | 3 Participants |
| Pertussis Case Group | 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 | Vaccinated, during first or second trimester | 0 Participants |
| Pertussis Case Group | 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 | Vaccinated, after pregnancy | 16 Participants |
| Pertussis Case Group | 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 | Unvaccinated | 49 Participants |
| Control Group | 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 | Vaccinated, after pregnancy | 25 Participants |
| Control Group | 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 | Unvaccinated | 78 Participants |
| Control Group | 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 | Vaccinated, before pregnancy | 2 Participants |
| Control Group | 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 | Vaccinated, during first or second trimester | 5 Participants |
| Control Group | 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 | Vaccinated, during third trimester | 11 Participants |
Comparison: To assess the effectiveness of maternal vaccination with Boostrix before pregnancy at preventing pertussis in infants \<2 months95% CI: [-12529, 99.46]
Comparison: To assess the effectiveness of maternal vaccination with Boostrix during third trimester of pregnancy at preventing pertussis in infants \<2 months95% CI: [-13.91, 98.03]
Comparison: To assess the effectiveness of maternal vaccination with Boostrix after pregnancy at preventing pertussis in infants \<2 months95% CI: [-87.4, 79.25]