Trial Outcomes & Findings for Seroprevalence of Bordetella Pertussis Antibodies and Anti-pertussis Antibody Response After a Single Dose of Tdap in Pregnant Thai Women (NCT NCT03498300)

Results Overview

Percentage of participants who were seropositive for anti-pertussis toxin antibodies (anti-PT IgG). The overall number of 129 participants is greater than the number of 42 participants include in the Particiant Flow Module because it was the sample size calculated based on the primary objective, which was the seroprevalence of anti-pertussis antibodies in pregnant Thai women. Randomized clinical trial on 42 seropositive participants was performed for one of the secondary objectives, which was to compare the different anti-PT IgG at delivery among seropositive participants who received Tdap to those who received Td.

Recruitment status

COMPLETED

Study phase

EARLY_PHASE1

Target enrollment

129 participants

Primary outcome timeframe

Four months

Results posted on

2020-03-24

Participant Flow

The sample size of 129 participants was calculated based on the primary objective. Randomized clinical trial on 42 seropositive participants was performed for one of the secondary objectives, which was to compare the different anti-PT IgG at delivery among seropositive participants who received Tdap to those who received Td.

Participant milestones

Participant milestones
Measure	Experimental A single dose of Tdap vaccine at GA 27 - 36 weeks	Active Comparator dT vaccine as standard protocol
Overall Study STARTED	21	21
Overall Study COMPLETED	18	13
Overall Study NOT COMPLETED	3	8

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Experimental n=18 Participants A single dose of Tdap vaccine at GA 27 - 36 weeks Tdap vaccine: A single dose of Tdap vaccine at GA 27 - 36 weeks	Active Comparator n=13 Participants dT vaccine as standard protocol	Total n=31 Participants Total of all reporting groups
Age, Continuous	29.8 years STANDARD_DEVIATION 7.4 • n=18 Participants	28.5 years STANDARD_DEVIATION 6 • n=13 Participants	29.2 years STANDARD_DEVIATION 6.8 • n=31 Participants
Sex/Gender, Customized Female	18 Participants n=18 Participants	13 Participants n=13 Participants	31 Participants n=31 Participants
Race and Ethnicity Not Collected	—	—	0 Participants Race and Ethnicity were not collected from any participant.

PRIMARY outcome

Timeframe: Four months

Percentage of participants who were seropositive for anti-pertussis toxin antibodies (anti-PT IgG). The overall number of 129 participants is greater than the number of 42 participants include in the Particiant Flow Module because it was the sample size calculated based on the primary objective, which was the seroprevalence of anti-pertussis antibodies in pregnant Thai women. Randomized clinical trial on 42 seropositive participants was performed for one of the secondary objectives, which was to compare the different anti-PT IgG at delivery among seropositive participants who received Tdap to those who received Td.

Outcome measures

Outcome measures
Measure	All Participants n=129 Participants After enrollment, a blood sample was obtained for determination of anti-PT IgG on the day of the first antenatal visit from all of the participants. If the anti-PT IgG level was 5 international units per milliliter (IU/ml) or more, the woman was considered to have seropositivity.	Active Comparator dT vaccine as standard protocol
The Seroprevalence of Anti-pertussis Toxin Antibodies (Anti-PT IgG) in Pregnant Thai Women	43 Participants	—

SECONDARY outcome

Timeframe: Eight months

Outcome measures

Outcome measures
Measure	All Participants n=18 Participants After enrollment, a blood sample was obtained for determination of anti-PT IgG on the day of the first antenatal visit from all of the participants. If the anti-PT IgG level was 5 international units per milliliter (IU/ml) or more, the woman was considered to have seropositivity.	Active Comparator n=13 Participants dT vaccine as standard protocol
Change From Baseline in Anti-pertussis Toxin Immunoglobulin G Levels Among Seropositive Participants Who Received Tdap to Those Who Received Td	42 IU/ml Interval 16.7 to 65.2	-7.4 IU/ml Interval -14.3 to -6.3

Adverse Events

Experimental

Serious events: 0 serious events

Other events: 12 other events

Deaths: 0 deaths

Active Comparator

Serious events: 0 serious events

Other events: 12 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure	Experimental n=18 participants at risk A single dose of Tdap vaccine at GA 27 - 36 weeks	Active Comparator n=13 participants at risk dT vaccine as standard protocol
Pregnancy, puerperium and perinatal conditions Gestational diabetes	11.1% 2/18 • Number of events 2 • Through study completion, an average of 11 months	23.1% 3/13 • Number of events 3 • Through study completion, an average of 11 months
Pregnancy, puerperium and perinatal conditions Preterm delivery	11.1% 2/18 • Number of events 2 • Through study completion, an average of 11 months	0.00% 0/13 • Through study completion, an average of 11 months
Pregnancy, puerperium and perinatal conditions Threatened preterm labor resulting in hospitalization	11.1% 2/18 • Number of events 2 • Through study completion, an average of 11 months	7.7% 1/13 • Number of events 1 • Through study completion, an average of 11 months
Pregnancy, puerperium and perinatal conditions Postpartum hemorrhage	5.6% 1/18 • Number of events 1 • Through study completion, an average of 11 months	0.00% 0/13 • Through study completion, an average of 11 months
Pregnancy, puerperium and perinatal conditions Congenital defects	5.6% 1/18 • Number of events 1 • Through study completion, an average of 11 months	15.4% 2/13 • Number of events 2 • Through study completion, an average of 11 months
Pregnancy, puerperium and perinatal conditions 1-minute Apgar score of 7 or less	11.1% 2/18 • Number of events 2 • Through study completion, an average of 11 months	7.7% 1/13 • Number of events 1 • Through study completion, an average of 11 months
Pregnancy, puerperium and perinatal conditions Prolonged hospitalization of the newborn after birth (more than 7 days)	11.1% 2/18 • Number of events 2 • Through study completion, an average of 11 months	38.5% 5/13 • Number of events 5 • Through study completion, an average of 11 months

Additional Information

Dr. Nalat Sompagdee

Faculty of Medicine Siriraj Hospital, Mahidol University

Phone: +6687-008-7100

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place