Table 1.

Characteristics of included studies

a.) Studies addressing safety outcomes
Authors and country	Setting/data sources	Study design/ period	Inclusion (I) and exclusion (E) criteria	Intervention/comparison	Final N/ N potentially eligible/ (%)	N Inter-vention group	N Control group	Outcomes
Munoz et al., 2014; USA [30]	3 National Institutes of Health’s Vaccine Treatment Evaluation Units	RCT, 2008–2012	I: Women, 18–45 years of age, with no chronic conditions, a singleton, uncomplicated pregnancy with normal first- or second-trimester screening test results; E: Women who received Tdap or any tetanus-containing vaccine within the prior 2 years	Tdap (Adacel®) at 30–32 WG vs. placebo	–	33	15	vaccine-related adverse outcomes; perinatal complications; pertussis illness in infants
Hoang et al., 2016; Vietnam [31]	Primary care	RCT, 2012–2013	I: Women, 18–41 years of age, with low risk for complications. E: Women with any serious underlying medical condition; febrile illness within 72 h before injection, receipt of TT vaccine in the past month; receipt of Tdap in the past 10 years; receipt of a vaccine, blood product or experimental medicine 4 weeks before or after injection; previous severe reaction to any vaccine	Tdap (Adacel®) at 20–30 WG vs. TT	–	51	48	short-term vaccine-related adverse outcomes; obstetric and perinatal complications
Halperin et al., 2018; Canada [32]	not specified, most likely outpatient hospital care	RCT, 2007–2014	I: Healthy, pregnant women 18–45 years of age assessed at ≥30 weeks’ gestation to be at low risk for complications; E: Women with high obstetrical risk, history of significant medical disorder or physician-diagnosed pertussis or receipt of Td or Tdap in the last 5 years; sensitivity to Td or Tdap, receipt of blood products or immunoglobulin within 3 months of study entry (except rhesus Ig), or receipt of any vaccines within 2 weeks of study vaccine (except for influenza vaccine).	Tdap (Adacel®) ≥30 WG vs. TT	273/304 (90%)	134	138	acute safety and pregnancy-related outcomes
Berenson et al., 2016; USA [33]	University hospital	RCS, 2012–2014	I: Singleton pregnancies delivered ≥27 WG; E: Women with < 4 clinic visits during pregnancy	Tdap (vaccine not specified) during pregnancy vs. no Tdap	–	1109	650	obstetric and perinatal complications
DeSilva et al., 2016; USA [34]	7 Vaccine Safety Datalink sites (Analysis of health insurance-based electronic health records)	RCS, 2007–2013	I: Singleton live births, women continuously insured from 6 months before LMP through 6 weeks postpartum, with ≥1 outpatient visit(s) during pregnancy. I Infants: birth weight and gestational age available; enrolled in health insurance for ≥4 months in first YoL, with ≥1 outpatient visit(s); E: Infants with exposures increasing risk for structural birth defects (maternal diabetes or use of teratogenic medications, congenital infections, and chromosomal abnormalities)	Tdap (vaccine not specified) during pregnancy vs. no Tdap	324,463 singleton live births	41,654	282,809	microcephaly and other selected major structural birth defects
DeSilva et al., 2017; USA [35]	7 Vaccine Safety Datalink sites (Analysis of health insurance-based electronic health records)	RCS, 2010–2013	I: Singleton live births, women continuously insured from 6 months before LMP through 6 weeks postpartum, with ≥1 outpatient visit(s) during pregnancy. I Infants: birth weight and gestational age available; enrolled in health insurance for ≥4 months in first YoL, with ≥1 outpatient visit(s); E: Women who received live virus vaccines during pregnancy	Tdap mostly at 27–36 WG (vaccine not specified) vs. no Tdap	197,654 /243,981 (81%) live births	45,008	152,556	obstetric and perinatal complications
Donegan et al., 2014; UK [36]	Primary care practices, (650 primary care general practice databases, 12.5 million patients)	RCS, 2012–2013 Tdap- and 2010–2012 control group	I a.) Short-term AE risk: women ≥12 years of age who received pertussis-containing vaccination during pregnancy with ≥28 days of follow-up data after vaccination; I b.) Risk throughout pregnancy: women ≥12 years of age with a recorded pregnancy outcome and estimated gestational age with follow-up of at least 44 weeks after the date of the LMP. I Historical cohort: women ≥12 years of age with a recorded pregnancy outcome from October 2010 to September 2012 and no record of a vaccine containing pertussis during or after pregnancy	TdaP-IPV (Repevax®) during pregnancy vs. no ap-vaccine	a.): 17,560/ 20,074 (87%); b.): 6185/20,074 (31%)		18,523	obstetric and perinatal complications
Griffin et al., 2018; New Zealand [37]	Nationwide linked administrative health databases	RCS, 2013	I: All pregnant women who reached 28–38 WG in 2013; E Women: pregnancies < 20 WG or missing maternal or gestational age; E Infants: live born babies < 28 WG or BW < 400 g	Tdap (Boostrix®) at 28–38 WG vs. no Tdap	68,550/73,817 (93%)	8178	60,372	obstetric, perinatal and neonatal outcomes
Kharbanda et al., 2014; USA [38]	2 Vaccine Safety Datalink sites (Analysis of health insurance-based electronic health records)	RCS, 2010–2012	I: Women 14–49  years of age at delivery with singleton pregnancies ending in live birth, continuously insured from 6 months before LMP through 6 weeks postpartum, ≥1 outpatient visit at an affiliated site and with birth weight and gestational age recorded; E: Women who received live virus vaccines during pregnancy or who received Tdap in the 7 days after the estimated pregnancy start date or in the 7 days before delivery; incomplete birth data	Tdap (mainly Adacel®) from 8 days after LMP to 8 days before delivery vs. no Tdap	123,494/300,607 (41%)	26,229	97,265	obstetric and perinatal complications
Kharbanda et al., 2016; USA [39]	Vaccine Safety Datalink sites (Analysis of health insurance-based electronic health records)	RCS, 2007–2013	see Kharbanda, 2014	Tdap (vaccine not specified) during pregnancy vs. no Tdap	427,097/631,256 (68%)	53,885	109,253	acute safety endpoints in 0–42 days after vaccination
Layton et al., 2017; USA [40]	MarketScan Commercial Claims and Encounters (Truven Health Analytics) claims databases of employer-based commercial health care insurance	RCS, 2010–2014	I: Women with livebirth or stillbirth deliveries; only first observed pregnancy per women; E: Women who delivered at ≤26 WG; women ≤18 years in 13 states with universal childhood immunization policies	Tdap (vaccine not specified) at ≥27 WG; Tdap < 27 WG vs. no Tdap	NR	≥27 WG: 123,780 < 27 WG: 25,037	871,177	acute safety endpoints in 0–42 days after vaccination; obstetrical and perinatal complications
Maertens et al., 2016; Belgium [15]	5 hospitals in Antwerp, Belgium	PCS, 2012–2014	I: Women 18–40 years of age with low risk for complications. E: Same as Hoang et al.	Tdap (Boostrix®) at 22–33 WG vs. no Tdap	NR	57	42	acute safety outcomes obstetric and perinatal complications
Morgan et al., 2015; USA [41]	Parkland clinic-based pre-natal and obstetrical care centers in Dallas County with centralized electronic medical charting system	RCS, 2013–2014	I: All women who delivered at Parkland	Tdap (vaccine not specified) at ≥32 WG vs. no Tdap	NR	7152	226	obstetric and neonatal outcomes
Shakib et al., 2013; USA [42]	Intermountain Healthcare database, Utah	RCS, 2005–2009	I: Pregnant women 12–45 years of age and their babies; E: Women whose pregnancy start date could not be determined; women who had documentation of Tdap vaccine within 3 days prior to delivery	Tdap (vaccine not specified) at any time during pregnancy vs. no Tdap	162,448	138	552	obstetric and perinatal complications; congenital anomalies, complex chronic conditions in 1st YoL
b.) Studies addressing effectiveness outcomes
Authors/country	Setting/data source	study design/period	Participants (Inclusion (I) and exclusion (E) criteria)	Intervention/comparator	N	Pertussis cases	control group	outcomes
Amirthalingam et al., 2014, UK [43]	notification data from enhanced surveillance for pertussis cases; and sentinel primary care data (Clinical Practice Research Datalink) for vaccination coverage calculations	RCS; screening method, 2008–2013	I: infants < 3 months of age; E: unknown maternal vaccination status, vaccination given within 7 days of birth; first primary infant vaccination before 7 days of disease onset	maternal Tdap-IPV (Repevax®) at 28–38 WG vs. no Tdap	NR	71	26,684	laboratory confirmed pertussis at < 2 and < 3 months of age
Amirthalingam et al., 2016, UK [16]	see Amirthalingam et al., 2014, UK [43]	RCS screening method, 2012–2015	see Amirthalingam et al., 2014, UK [43]	maternal Tdap-IPV (Repevax®, Boostrix-Polio®) at 28–38 WG vs. no Tdap	NR	192	72,781	laboratory confirmed pertussis at < 2 and < 3 months of age; pertussis related deaths
Baxter et al., 2017, USA [44]	Kaiser Permanente Northern California (KPNC) medical care data	RCS, 2010–2015	I: infants born in KPNC hospitals 2010–2015; full term (> = 37 WG); enrolled in Kaiser health plan by age 4 months; mother continuously enrolled in KPNC health plan; mother born before 1996	maternal Tdap vaccination (Boostrix®, Covaxis®) at least 8 days before birth vs. no Tdap	148,981	17	148,964	laboratory confirmed pertussis at < 2 months of age
Becker-Dreps et al., 2018, USA [45]	commercial insurance claims data	RCS, 2010–2014	I: infants </= 18  months of age, delivered between June 2010 and Dec. 2014; First delivery per women; singleton deliveries occurring > 26 WG; E: non-continuous insurance enrolment from pregnancy onset until 7 days post-delivery	maternal Tdap vaccination (vaccine not specified) vs. no Tdap	632,825	112	632,713	laboratory confirmed pertussis at < 2 months of age; pertussis-related hospitalization
Bellido-Blasco et al., 2017, Spain [46]	community-based data; cases were identified via computerized mandatory notification system	CCS, 2015–2016	I: cases: unvaccinated infants < 3 months old, with confirmed pertussis; controls: three paired controls by age (difference less than 15 days) per case; two controls: same paediatrician/family doctor as case; third control: same maternity clinic as case; controls: unvaccinated	maternal Tdap vaccination (vaccine not specified) vs. no Tdap	88	22	66	laboratory confirmed pertussis at < 3 months of age
Dabrera et al., 2015, England and Wales [47]	community-based data; cases were identified via notification system; controls were 2 infants born consecutively after pertussis case from the same practice	CCS, 2012–2013	E infants: aged ≥8 weeks, unknown vaccination status of mother; E controls: known clinical or microbiological diagnosis of pertussis	maternal Tdap-IPV (Repevax®) at any time in pregnancy vs. no Tdap	113	58	55	laboratory confirmed pertussis at <2 months ofage
Saul et al., 2017, Australia [48]	cases were identified via notification system; controls: infant born +/−3 days as case in the maternity clinic of the local health district in which the case was notified	CCS, 2015–2016	E controls: cough illness within two weeks of the onset of the illness in the matched case	maternal Tdap at ≤2 weeks before birth with a 3-component acellular pertussis vaccine vs. no Tdap	96	48	48	laboratory confirmed pertussis at < 3 months of age; pertussis-related hospitalization
Skoff et al., 2017, USA [49]	cases were identified via surveillance in 6 Emerging Infection Program Network sites; controls were hospital-matched	CCS, 2011–2014	I: infants ≥2 days old, residing in the catchment area on their cough onset date, were born in a hospital in their state of residence, were delivered at ≥37 WG, were not adopted or in foster care, and did not live in a residential care facility. E controls: pertussis diagnosis prior to the cough onset date of the corresponding case infant	any pertussis-containing vaccine at any time in pregnancy vs. no Tdap	6252	240	535	laboratory confirmed pertussis at <2 months of age; pertussis-related hospitalization

ap-vaccine acellular pertussis vaccine, BW birth weight, LMP last menstrual period, NR not reported, RCT randomized controlled trial, RCS retrospective cohort study, TT Tetanus-vaccine, YoL year of life, CCS case-control-study, dT5aP-IPV diphteria-tetanus-5-component-acelluar-pertussis-inactivated-polio-vaccine, dT3aP-IPV diphteria-tetanus-3-component-acelluar-pertussis-inactivated-polio-vaccine, NR not reported, WG weeks of gestation