What are the side effects of the Tdap & DTaP Vaccine?

What do adverse-event databases report for tdap vaccine side effects? Methodology-transparent page: VAERS and international AE databases by reaction category. Includes clinical trials, graded documented AEs, and disease-benefit context — not medical advice. Also covers: dtap vaccine side effects, tdap shot side effects, tdap while pregnant side effects.

Does a VAERS or pharmacovigilance report prove the Tdap & DTaP Vaccine caused a reaction?

No. VAERS and similar passive-surveillance systems (EudraVigilance, VigiAccess, Yellow Card, Lareb, DAEN) collect spontaneous, unverified reports. A report documents a temporal association, not a confirmed cause, and under-reporting or stimulated reporting can distort counts. Compare report counts with clinical trial and epidemiological data before drawing conclusions.

Who manufactures the Tdap & DTaP Vaccine?

Tdap & DTaP Vaccine products on the U.S. market are manufactured by Sanofi and GSK.

What does the evidence say about the Tdap & DTaP Vaccine?

Tdap booster extends pertussis protection into adolescence and adulthood

DTaP/Tdap Side Effects: Infanrix, Daptacel, Boostrix, Adacel

Name: DTaP/Tdap Vaccine
Brand: Daptacel
SKU: dtap

Evidence state

For each outcome: the specific question, what controlled studies found, and how certain that evidence is on the GRADE scale (high, moderate, low, very low). Ratings are editorial judgments by the site applying GRADE to the studies in the table below — observational evidence starts at low and is rated up for large, consistent effects or a dose/age gradient, and down for inconsistency or imprecision (Methods). Where an effect is confined to a subgroup (for example young males), the question says so. "Not searched" means no controlled study has been compiled here yet; it is not a finding that the outcome is rare or caused by the vaccine.

Outcome & question	Finding & certainty	Why this rating
Febrile seizure DTaP (acellular) vs whole-cell DTP (no longer used in the US)	no increase detected with DTaP; increased with whole-cell DTP Low (DTaP) certaintyModerate (whole-cell DTP) certainty	DTaP: one large risk-interval study. Whole-cell DTP: start low; +2 very large effect (RR 5.7) in a large VSD cohort. Studies: Huang 2010, Barlow 2001. See table
Pregnancy outcomes Tdap during pregnancy	no increase in preterm birth, small-for-gestational-age, hypertensive disorders or neonatal sepsis; a small rise in coded chorioamnionitis in early studies was not confirmed later Low certainty	Large VSD cohorts with precise nulls for birth outcomes; chorioamnionitis inconsistent (RR 1.19–1.23 coded diagnosis vs HR 0.96 in a later cohort). Studies: Kharbanda 2014, DeSilva 2017, Greenberg 2023. See table
Guillain-Barré syndrome Td	no increased risk detected Very low certainty	Single case-centered study with a wide interval. Studies: Baxter 2013. See table
Type 1 diabetes Pertussis-containing vaccines	no increased risk detected Low certainty	Case-control study; IOM 2011 favours rejection. Studies: DeStefano 2001, IOM 2011. See table
Anaphylaxis	Not searched	No controlled-study result is compiled for this outcome yet.
Myocarditis or pericarditis	Not searched	No controlled-study result is compiled for this outcome yet.
Immune thrombocytopenia	Not searched	No controlled-study result is compiled for this outcome yet.

1. Basic Information

Diseases Protected Against

Diphtheria: Toxin-mediated bacterial infection (Corynebacterium diphtheriae) causing a pseudomembrane in the throat and airway obstruction; toxin can cause myocarditis and peripheral neuropathy. Case-fatality ~5–10%, higher in young children. Rare in the U.S. due to vaccination (~0–5 cases/year).
Tetanus (Lockjaw): Toxin-mediated infection (Clostridium tetani) from wound contamination. Causes painful muscle rigidity and spasms; can cause respiratory failure. Case-fatality ~10–20%. Universal; not contagious, so herd immunity does not apply. ~30 cases/year in U.S.; nearly all in unvaccinated or under-vaccinated persons.
Pertussis (Whooping Cough): Bacterial respiratory infection (Bordetella pertussis) causing paroxysmal cough, post-tussive emesis, and apnea in infants. Highest mortality in infants <3 months. Cyclical outbreaks every 3–5 years. The switch from whole-cell (DTwP) to acellular (DTaP) vaccine in the 1990s reduced reactogenicity but may have resulted in less durable immunity.

CDC Recommended Schedule (United States, 2025)

Dose/Age	Product	Notes
2 months	DTaP	Minimum age 6 weeks
4 months	DTaP
6 months	DTaP
15–18 months	DTaP	4th dose; minimum 6 months after dose 3
4–6 years	DTaP	5th dose; not needed if 4th dose given at ≥4 years
11–12 years	Tdap	Single booster; can be given at ≥7 years
Pregnancy (27–36 weeks)	Tdap	Every pregnancy, regardless of prior Tdap history; primarily to protect newborn from pertussis via maternal antibody transfer
Every 10 years (adults)	Td or Tdap	Decennial booster; one Tdap replaces one Td booster

Source: CDC ACIP, 2025 Child & Adolescent and Adult Immunization Schedules.

Licensed Products (U.S.)

Daptacel^® (Sanofi) — DTaP for infants/children. Licensed 2002.
Infanrix^® (GSK) — DTaP for infants/children. Licensed 1997.
Adacel^® (Sanofi) — Tdap for ages 10–64. Licensed 2005. Reduced diphtheria toxoid and pertussis antigen content compared to DTaP.
Boostrix^® (GSK) — Tdap for ages ≥10. Licensed 2005.
Combination vaccines: Kinrix (DTaP-IPV), Quadracel (DTaP-IPV), Pediarix (DTaP-HepB-IPV), VAXELIS (DTaP-IPV-Hib-HepB), Pentacel (DTaP-IPV-Hib). Combination vaccines use the same DTaP components.

Licensed DTaP/Tdap vaccine products

Each product has its own page with package-insert ingredients, side-effect data, lot lookup and comparisons with the other brands.

Daptacel — Sanofi Pasteur
combination; intramuscular; adjuvant: Aluminum phosphate
Infanrix — GlaxoSmithKline Biologicals
combination; intramuscular; adjuvant: Aluminum hydroxide

Ingredients (Package Insert)

Structured composition for 2 branded products covered on this page, taken from FDA-approved package inserts (DailyMed / manufacturer prescribing information). Lists are per product — formulations differ by manufacturer and presentation. Click an ingredient name to open its safety-context page when available.

Combination Intramuscular (IM) Adjuvant: Aluminum phosphate No preservative (typical single-dose) Aluminum phosphate Formaldehyde Adjuvant: Aluminum hydroxide Aluminum hydroxide Polysorbate 80

Daptacel Sanofi Pasteur · Combination

Delivery

Route: Intramuscular (IM)

Form: Suspension for injection

Dose volume: 0.5 mL

Presentation: single-dose vial

Encapsulation / delivery vehicle

None (no nanoparticle/VLP encapsulation system)

Antigens

Antigen	Type	Amount / dose
Diphtheria toxoid	Toxoid	15 Lf
Tetanus toxoid	Toxoid	5 Lf
Pertussis toxin (detoxified)	Protein subunit	10 mcg
Filamentous hemagglutinin (FHA)	Protein subunit	5 mcg
Pertactin (PRN)	Protein subunit	3 mcg
Fimbriae types 2 and 3 (FIM)	Protein subunit	5 mcg

Adjuvants

Aluminum phosphate — 0.33 mg aluminum per 0.5 mL

Preservatives

None — 2-phenoxyethanol is present as a stabilizer, not as a preservative (label wording).

Excipients & residuals

Ingredient	Category	Amount	Role
2-Phenoxyethanol	Stabilizer	3.3 mg (0.6% v/v)	stabilizer (not labeled as preservative)
Formaldehyde	Residual (inactivating agent)	≤5 mcg residual	residual
Glutaraldehyde	Residual (inactivating agent)	<50 ng residual	residual
Water for injection	Diluent	q.s.	vehicle

Source: DailyMed · Verified 2026-07-09

Infanrix GlaxoSmithKline Biologicals · Combination

Delivery

Route: Intramuscular (IM)

Form: Suspension for injection

Dose volume: 0.5 mL

Presentation: single-dose vial or prefilled syringe

Encapsulation / delivery vehicle

None (no nanoparticle/VLP encapsulation system)

Antigens

Antigen	Type	Amount / dose
Diphtheria toxoid	Toxoid	25 Lf
Tetanus toxoid	Toxoid	10 Lf
Inactivated pertussis toxin (PT)	Protein subunit	25 mcg
Filamentous hemagglutinin (FHA)	Protein subunit	25 mcg
Pertactin (PRN)	Protein subunit	8 mcg

Adjuvants

Aluminum hydroxide — ≤0.625 mg aluminum per dose

Preservatives

None — Single-dose presentation; label states no preservative.

Excipients & residuals

Ingredient	Category	Amount	Role
Formaldehyde	Residual (inactivating agent)	≤100 mcg residual	residual
Polysorbate 80	Surfactant	≤100 mcg	surfactant
Sodium chloride	Buffer	label quantity	tonicity

Source: FDA package insert · Verified 2026-07-09

ⓘ How to read this section

Ingredient lists are sourced from official package inserts for the specific brands named above. Formulations can change between lots and over time — verify against the current label before any clinical decision. Presence of a substance does not by itself indicate harm; toxicology is dose-, route-, and context-dependent. Browse the full ingredient database: Vaccine Ingredients index.

Causality assessment & potential mechanisms

Conditions below combine WHO-style causality levels with potential biological mechanisms from the site mechanism catalog (ae_mechanisms_catalog.json). HRSA VICP table listing (where shown) indicates a compensable temporal association under U.S. program rules — not automatic proof of causation for every case. Mechanisms are hypothesis-level pathways with graded evidence.

Condition	Time window	Causality	Potential mechanism(s)
Anaphylaxis HRSA table	0–1 days	Very likely / Probable Evidence: High	IgE-mediated hypersensitivity (anaphylaxis) (primary · hypersensitivity) Pre-existing or newly formed IgE against vaccine antigens or excipients (e.g., gelatin, egg proteins, PEG, polysorbate) triggers mast-cell and basophil degranulation with systemic mediator release.
Guillain-Barré Syndrome (GBS) HRSA table	0–42 days	Possible Evidence: Moderate	Molecular mimicry → Guillain-Barré syndrome (primary · molecular_mimicry) Vaccine- or infection-triggered immune responses cross-react with peripheral-nerve gangliosides or myelin components, producing demyelinating or axonal polyneuropathy.
Brachial Neuritis HRSA table	0–28 days	Very likely / Probable Evidence: High	Immune-mediated brachial neuritis (primary · molecular_mimicry) Immune-mediated inflammation of brachial plexus nerves after antigenic stimulation (classically tetanus toxoid-containing vaccines), producing severe shoulder/arm pain and weakness.
Syncope (Fainting) HRSA table	0–1 days	Possible Evidence: Moderate	Vasovagal (needle) syncope (primary · vasovagal) Pain, anxiety, or orthostatic stress from injection triggers parasympathetic surge with bradycardia and hypotension, producing transient loss of consciousness—common in adolescents.
SIRVA HRSA table	0–2 days	Very likely / Probable Evidence: High	SIRVA — incorrect injection into shoulder structures (primary · procedural) Needle placement into the subdeltoid/subacromial bursa or joint rather than deltoid muscle causes prolonged local inflammation and restricted range of motion (procedural, not antigen-specific).
Extensive limb swelling (booster doses)	0–7 days	Possible Evidence: Moderate	Adjuvant-driven local and systemic reactogenicity (primary · innate_inflammation) Aluminum or other adjuvants (e.g., AS01B) amplify innate immune signaling, producing injection-site inflammation and transient systemic symptoms (fever, myalgia, fatigue).

Framework: WHO causality + HRSA VICP (where applicable) + AE mechanism catalog. Last updated: 2026-07-18. Schema: schemas/vaccine_injury_table.schema.json · Mechanisms: schemas/ae_mechanism.schema.json. Not medical or legal advice.

2. Pre-Licensure Clinical Trial Data

Licensure trial design (ICAN / OpenVAERS)

The table below reproduces ICAN’s No Placebo Table rows for U.S. childhood-schedule products relevant to this page — including the control/comparator used in FDA licensing trials (not always saline placebo). OSMF presents this for transparency; it is not an endorsement of ICAN interpretations.

Vaccine	Brand	Manufacturer	Doses (schedule)	Ages injected	Control / comparator	Placebo	Safety review window
DTaP	Infanrix	GSK	15	2M 4M 6M 15M 4Y	DTP	No	30 days
DTaP	Daptacel	Sanofi	15	2M 4M 6M 15M 4Y	DT or DTP	No	Up to 2 months + 1 trial 6 months
Tdap	Adacel	Sanofi	3	11Y	Td, for adults	No	6 months
Tdap	Boostrix	GSK	3	11Y	Decavac or Adacel	No	6 months

Source: OpenVAERS — No Placebo Table · ICAN original PDF · Attribution: Informed Consent Action Network (ICAN) via OpenVAERS · Last fetched: 2026-07-16. For many trials listing '6 months' safety review, ICAN notes review was typically ~30 days post-injection with a phone call at 6 months.

Historical Context: DTwP to DTaP Transition

Whole-cell pertussis (DTwP) vaccines were introduced in the 1940s and were highly effective but reactogenic—commonly causing high fever, prolonged crying, and febrile seizures. Safety concerns (including a hypothesized association with encephalopathy, later not confirmed) led to the development of acellular pertussis (DTaP) vaccines, licensed in the U.S. between 1991 (first DTaP) and 2002 (Daptacel). The U.S. switched from DTwP to DTaP for all doses by 2002.

DTaP Pre-Licensure Trials (Daptacel / Infanrix)

The pivotal DTaP trials enrolled several thousand infants each. Daptacel (trial P3T06) included ~4,983 infants who received Daptacel vs. ~1,651 who received DTwP. Infanrix trials were multinational and similarly sized.

Metric	DTaP Data	Evidence Strength
Combined DTaP safety database (pre-licensure)	~10,000+ infants across all products	Moderate
Efficacy (pertussis, DTaP)	~80–85% (clinical pertussis definition) in initial trials; waning immunity documented post-licensure	Strong
Safety follow-up duration	Generally 30 days post-dose for SAEs; limited long-term follow-up	Limited

Tdap Pre-Licensure Trials (Adacel / Boostrix, 2005)

Adacel was evaluated in ~4,500 adolescents/adults. Boostrix in ~4,100. Both compared to Td (tetanus-diphtheria) vaccine. Primary endpoint was immunogenicity non-inferiority to the adult Td with demonstration of pertussis antibody responses.

Most Common Adverse Reactions

Reaction	DTaP (infants)	Tdap (adolescents/adults)
Injection site pain	~25–40%	~60–75%
Injection site swelling	~15–25%	~20–30%
Fever ≥38°C	~15–30% (lower than DTwP ~40–60%)	~3–8%
Irritability/fussiness	~30–55%	N/A
Drowsiness/decreased activity	~30–45%	N/A
Headache	N/A	~20–30%
Fatigue	N/A	~20–30%

Sources: Respective prescribing information; FDA review documents. Rates vary by study, product, and dose number.

Key Limitations

No placebo control: Modern DTaP trials used DTwP or other DTaP products as comparators, not placebo. This is ethically appropriate but limits the ability to detect absolute adverse event rates attributable to vaccination.
Waning immunity: Pre-licensure trials demonstrated initial efficacy but were not designed to assess durability. Post-licensure data have revealed substantially shorter duration of protection from acellular pertussis vaccines compared to whole-cell vaccines.
Combination vaccine complexity: Safety signals in combination vaccines (DTaP-IPV-Hib-HepB) are difficult to attribute to individual antigens.
Tdap in pregnancy: Initial licensure did not include safety data in pregnancy; the recommendation for every-pregnancy Tdap is supported by post-licensure observational data, not pre-licensure RCTs.

3. Post-Licensure Safety Data

Vaccine Safety Datalink (VSD)

The VSD has conducted extensive surveillance on DTaP/Tdap vaccines. Key findings:

Febrile seizures: DTaP is associated with a small increased risk of febrile seizures in the 0–1 day window post-vaccination in infants, particularly with concomitant PCV and influenza vaccines. Risk is ~1 per 15,000–25,000 doses.
Extensive limb swelling (ELS): With DTaP, ELS (involving ≥2/3 of the upper arm) is reported in ~2–6% of children after the 4th and 5th booster doses. Self-limited; not a contraindication to subsequent doses.
Tdap in pregnancy: Multiple VSD studies have found no increased risk of adverse pregnancy outcomes (preterm birth, low birth weight, congenital anomalies) or maternal adverse events associated with Tdap during pregnancy. A VSD study (Kharbanda et al., 2014; N>29,000 pregnancies) found no association with adverse birth outcomes.
Guillain-Barré Syndrome (GBS): No consistent signal with DTaP. For Tdap, VSD rapid cycle analysis found no significantly elevated GBS risk, though tetanus toxoid-containing vaccines have been hypothesized to have a very small association in some studies (see Section 4).

VAERS

VAERS Metric (DTaP/Tdap, cumulative)	Approximate Figures
Total DTaP doses distributed (estimated)	>1 billion doses globally since the 1990s
Most commonly reported AEs	Injection site reactions, fever, irritability (infants); injection site pain, headache, fatigue (Tdap in adolescents/adults)
Notable signal	Hypotonic-hyporesponsive episodes (HHE) in infants—resolved and well-characterized as rare, self-limited events associated primarily with DTwP; far less common with DTaP (~1–2 per 100,000 doses)

⚠ Critical Caveat

VAERS data represent unverified reports temporally associated with vaccination. A report to VAERS does not mean the vaccine caused the event. VAERS cannot be used to calculate incidence rates or establish causality.

Major Independent Reviews

Review	Year	Key Findings
IOM — "Adverse Effects of Vaccines"	2012	Favors acceptance of causal relationship for anaphylaxis and shoulder injury related to vaccine administration (SIRVA). Favors rejection for type 1 diabetes, autism, and SIDS. Evidence inadequate for GBS and chronic urticaria.
IOM — "DTaP and SIDS"	2003	Rejects causal association between DTaP and SIDS. Multiple large studies consistently find no association.
NASEM — Vaccine Safety Review	2020	No evidence the recommended schedule (including DTaP/Tdap) is associated with adverse neurodevelopmental outcomes.

VAERS reports per million doses

U.S. VAERS reports for vaccinations given 2006–2024, divided by the 879 million doses distributed in the same years (HRSA, from CDC data).

All reports

132

per million doses (131–132) · 115,599 reports

Serious reports

11.2

per million doses · 9,880 reports (death, life-threatening, hospitalised or disabled)

Reports with a death

1.31

per million doses · 1,150 reports

These are reporting rates: they mix real reactions, coincidental events and reports of conditions that would have happened anyway, and they depend on how actively each vaccine is watched. Doses are distributed, not administered. Combination vaccines count toward each component in both numerator and denominator. Compare with the observed-vs-expected analysis and the controlled studies above. Data: vaers_reporting_rates.json.

All vaccines, per million doses

Vaccine	All	Serious	Death
pcv	266	28.1	3.23
rotavirus	157	27.9	4.08
hpv	335	25.3	2.00
hib	126	19.7	3.25
polio	152	17.6	2.77
mmr	320	15.3	0.94
varicella	372	14.1	0.84
hepatitis-b	110	12.7	2.15
meningococcal	214	11.8	0.70
dtap	132	11.2	1.31
hepatitis-a	152	8.5	0.58
influenza	68	5.4	0.48

What controlled safety studies found

Unlike VAERS counts, these studies compare vaccinated people with a control group or control time window, so they can estimate whether a risk is raised and by how much. 14 results for DTaP/Tdap vaccines: 4 found an increased risk of a specific outcome, 9 found no increased risk.

Outcome	Design & population	Estimate (95% CI)	Excess per million doses	Finding	Source
Chorioamnionitis Tdap in pregnancy	retrospective cohort (VSD, 7 sites) Pregnancies, US 2010-2013 (197,564)	RR (adjusted rate ratio) 1.23 (1.17–1.28)	—	increased risk	DeSilva M et al., 2017, Vaccine doi:10.1016/j.vaccine.2017.05.041; PMID 28552511
Chorioamnionitis (coded diagnosis) Tdap in pregnancy	retrospective cohort (VSD) Pregnant women, US 2010-2012	RR (adjusted) 1.19 (1.13–1.26)	—	increased risk	Kharbanda EO et al., 2014, JAMA doi:10.1001/jama.2014.14825; PMID 25387187
Febrile seizures DTP (whole-cell; no longer used in US)	cohort (VSD) Children, US	RR 5.7 (1.98–16.42)	—	increased risk	Barlow WE et al., 2001, N Engl J Med doi:10.1056/NEJMoa003077; PMID 11547719
Febrile seizures Infant vaccine visits (median 4 vaccines incl. DTaP, PCV, Hib, IPV, HepB, RV)	self-controlled risk interval (VSD) Infants 1-5 mo, US 2006-2011 (585,342 vaccination visits)	IRR 23 (5.13–100.8)	—	increased risk	Duffy J et al., 2017, Pediatr Neurol doi:10.1016/j.pediatrneurol.2017.08.005; PMID 28958404
Chorioamnionitis Tdap in pregnancy	retrospective cohort (VSD, 8 sites, IPW Cox) Pregnant people 15-49 y, US 2016-2018 (118,211)	HR (adjusted) 0.96 (0.9–1.03)	—	no increased risk detected	Greenberg V et al., 2023, Vaccine doi:10.1016/j.vaccine.2023.04.043; PMID 37117057
Guillain-Barre syndrome Td (tetanus-diphtheria)	case-centered (KPNC) Adolescents/adults, Kaiser Northern California	OR 1.4 (0.3–4.5)	—	no increased risk detected	Baxter R et al., 2013, Clin Infect Dis doi:10.1093/cid/cit222; PMID 23580737
Hypertensive disorders of pregnancy Tdap in pregnancy (before 20 wk)	retrospective cohort (VSD) Pregnant women, US 2010-2012	RR (adjusted) 1.09 (0.99–1.2)	—	no increased risk detected	Kharbanda EO et al., 2014, JAMA doi:10.1001/jama.2014.14825; PMID 25387187
ITP Tdap	cohort, risk vs control intervals (VSD) Adolescents 11-17 y, US	—	—	inconclusive	O'Leary ST et al., 2012, Pediatrics doi:10.1542/peds.2011-1111; PMID 22232308
Neonatal sepsis Tdap in pregnancy	retrospective cohort (VSD) Infants of vaccinated vs unvaccinated mothers, US 2010-2013	RR (adjusted rate ratio) 1.06 (0.91–1.23)	—	no increased risk detected	DeSilva M et al., 2017, Vaccine doi:10.1016/j.vaccine.2017.05.041; PMID 28552511
Preterm birth Tdap in pregnancy	retrospective cohort (VSD, 2 California sites) Pregnant women, singleton live births, US 2010-2012 (123,494)	RR (adjusted) 1.03 (0.97–1.09)	—	no increased risk detected	Kharbanda EO et al., 2014, JAMA doi:10.1001/jama.2014.14825; PMID 25387187
Seizures (febrile or afebrile) DTaP	risk-interval cohort + SCCS (VSD) Children 6 wk-23 mo, US (433,654)	IRR 0.91	—	no increased risk detected	Huang WT et al., 2010, Pediatrics doi:10.1542/peds.2009-1496; PMID 20643726
Small for gestational age Tdap in pregnancy	retrospective cohort (VSD) Pregnant women, US 2010-2012	RR (adjusted) 1.0 (0.96–1.06)	—	no increased risk detected	Kharbanda EO et al., 2014, JAMA doi:10.1001/jama.2014.14825; PMID 25387187
Type 1 diabetes Acellular pertussis-containing vaccines	case-control (VSD, 4 HMOs) Children born 1988-1997, US	OR 0.92 (0.53–1.57)	—	no increased risk detected	DeStefano F et al., 2001, Pediatrics doi:10.1542/peds.108.6.e112; PMID 11731639
Type 1 diabetes DT, TT or aP-containing vaccines	expert causality review (IOM 2011) General	—	—	no increased risk detected	Institute of Medicine (Stratton K et al., eds.), 2011, Adverse Effects of Vaccines: Evidence and Causality, National Academies Press doi:10.17226/13164

Benefit and risk on the same scale (per million)

Bars are drawn to scale within each comparison. Disease risks are per case of the disease; vaccine risks are the excess above background per dose, from controlled studies. How likely someone is to catch the disease, without vaccination, decides how these weigh up for an individual.

No single study measured both risks in the same population for this vaccine, so no side-by-side ratio is shown; the two lists below come from different studies, eras and populations.

Serious outcomes of the disease (per million cases)

Pertussis: Hospitalization; pneumonia; seizures	630,000	Infants <6 months with reported pertussis, US 1997-2000 · source
Pertussis: Hospitalization (DERIVED from annual means)	379,000	US infants (<1 year) with reported pertussis, 2000-2017 · source
Pertussis: Hospitalization	330,000	Infants <12 months with pertussis (current CDC page; no era stated) · source
Diphtheria: Death, unvaccinated without proper treatment	300,000	Unvaccinated individuals without adequate treatment · source
Tetanus: Death (case-fatality)	220,000	Unvaccinated persons with tetanus (US) · source
Pertussis: Pneumonia	186,000	Infants <6 months with reported pertussis, US 2000-2017 · source
Tetanus: Death (case-fatality)	110,000	Reported US tetanus cases, 'recent years' (Pink Book) · source
Pertussis: Death (DERIVED case-fatality from annual means)	5,100	US infants (<1 year) with reported pertussis · source

Compiled from study abstracts and FDA/CDC pages, verified 2026-10-09; full table with every source on vaccine safety studies. Data: active_surveillance_results.json, disease_risks.json.

Trials, timing and other data sources

When do reported events start? (time to onset)

Days from vaccination to onset in U.S. VAERS reports (0–180 days). A causal reaction usually starts inside a characteristic window; but people also report what happens soon after a shot, so each event is compared with all other reports for this vaccine. The Weibull shape measures bunching (below 1 = most onsets early).

Event	Reports	Median days	In risk window	Shape (95% CI) vs others	Reading
Seizure (any)	8,931^*	1	96% (others 98%)	0.71 (0.70–0.73) vs 0.74	same timing as other reports
Syncope	4,374	0	96% (others 76%)	0.81 (0.77–0.86) vs 0.74	spread later than other reports
Febrile seizure	1,956	1	97% (others 98%)	0.77 (0.74–0.82) vs 0.74	same timing as other reports
Intussusception	1,081	9	62% (others 53%)	0.84 (0.81–0.88) vs 0.74	spread later than other reports
Sudden infant death	924	3	75% (others 94%)	0.81 (0.77–0.86) vs 0.74	spread later than other reports
Anaphylaxis	454	0	94% (others 76%)	0.70 (0.63–0.80) vs 0.74	same timing as other reports
Guillain-Barré syndrome	405	13	85% (others 54%)	1.00 (0.92–1.06) vs 0.74	spread later than other reports
Herpes zoster	251	5	73% (others 54%)	0.60 (0.56–0.65) vs 0.74	clusters earlier than other reports
ADEM / encephalitis	240	5	81% (others 54%)	0.81 (0.75–0.93) vs 0.74	same timing as other reports
Bell's palsy / facial paralysis	142	2	77% (others 54%)	0.71 (0.64–0.81) vs 0.74	same timing as other reports
Immune thrombocytopenia	130	12	91% (others 54%)	1.00 (0.87–1.19) vs 0.74	spread later than other reports
Transverse myelitis	116	12	78% (others 54%)	0.92 (0.82–1.06) vs 0.74	spread later than other reports

Timing alone cannot establish causation; it can make it more or less plausible. ^*Fitted on a random sample of 5,000 of these reports. Data: vaers_onset.json.

VAERS Reporting Data — Halma & Varon (2025), DARE-SAFE

The DARE-SAFE paper (Halma & Varon, Pharmacoepidemiology 2025, CC BY 4.0) analyzed VAERS reports for vaccines administered in the United States from 2006–2022. The following data are extracted from Table 1 of that paper for this vaccine (DTaP only (excludes combination vaccines like DTaP-HepB-IPV, DTaP-IPV-Hib, etc.)):

Metric	Value
U.S. doses administered (2006–2022)	122,237,653
Total VAERS AE reports	25,629
AE reporting rate (per 100,000 doses)	21.0
Total death reports	656
Death reporting rate (per 100,000 doses)	0.537
AE-to-Death ratio	39:1

Source: Halma, M.; Varon, J. DARE-SAFE. Pharmacoepidemiology. 2025. DOI: 10.3390/pharma4020007. CC BY 4.0. Data from Table 1.

📚 Important Interpretive Caveats (from the paper itself)

Reporting rate ≠ incidence rate. VAERS is a passive, unverified system. A report means someone submitted a claim of temporal association, not a confirmed causal event. The paper is explicit that causality cannot be inferred from these numbers alone.
Reporting behavior is not uniform. More serious, unusual, or media-salient events are reported at much higher rates than mild ones. Products receiving more public, media, legal, and clinical attention (particularly COVID-19 vaccines, which also benefited from V-safe active-surveillance prompts and CICP compensation pathways) generate more reports per dose regardless of true risk.
Age and comorbidity confounding is not adjusted. COVID-19 vaccines were disproportionately administered to elderly and comorbid populations (nursing homes, 65+, high-risk groups in early 2021) with much higher background all-cause mortality than the general child/working-age population. Some fraction of temporally-associated deaths would occur regardless of vaccination, and the paper does not perform a background-rate comparison.
Stimulated reporting is a known, documented phenomenon. Media coverage, plaintiff attorney solicitation, and advocacy campaigns — all independently inflate VAERS reporting propensity. The paper cites this literature but does not correct for it.
Small-denominator rows are unreliable. Rates computed from small denominators (e.g., monovalent measles, DT, mumps, rubella) have enormous statistical uncertainty and should not be compared to vaccines with hundreds of millions of administered doses without noting the wide confidence intervals.

Source: Halma, M.; Varon, J. DARE-SAFE: Denominator-Adjusted Rate Estimates of Substance Adverse Events Frequency Evaluation in Pharmaceuticals and Vaccines. Pharmacoepidemiology. 2025, 4, 7. DOI: 10.3390/pharma4020007. CC BY 4.0.

Tdap — Additional VAERS Data (DARE-SAFE 2025)

The DARE-SAFE paper also reports separate data for the adult/adolescent Tdap formulation:

Metric	Tdap Value	DTaP Value (for comparison)
U.S. doses (2006–2022)	358,134,237	122,237,653
Total AE reports	39,153	25,629
AE rate /100k	10.9	21.0
Death reports	59	656
Death rate /100k	0.0165	0.537
AE:Death ratio	664:1	39:1

Source: Halma, M.; Varon, J. DARE-SAFE. Pharmacoepidemiology. 2025. DOI: 10.3390/pharma4020007.

Passive Surveillance: AE Type Breakdown (Multi-System)

Side-by-side view of U.S. VAERS, Health Canada Canada Vigilance, Japan JADER (PMDA), EU EudraVigilance, and live-scraped international systems via SurVigilance (VigiAccess, Lareb, DAEN, DMA, Medsafe). SurVigilance panels show MedDRA PT mention totals (not individual-case counts). Category assignment uses keyword matching — approximate, not official SOC coding. VAERS files on this site are built from the public VAERS download. FAERS figures use the public quarterly FAERS files. Counts are mentions or reports, not incidence.

VAERS (United States)

Canada Vigilance (Canada)

JADER (PMDA, Japan)

EudraVigilance (EU)

32,489
individual cases · adrreports.eu DAP export (up to 28/06/2026)
Reaction SOC breakdown not included in this workbook export.

SurVigilance: VigiAccess · Lareb · DAEN · DMA · Medsafe

VigiAccess (WHO)

Lareb (Netherlands)

DAEN (Australia)

DMA (Denmark)

Denmark DMA interactive ADR search is currently offline (Danish Medicines Agency IT transition; public overviews frozen at 12 Mar 2024). Live product PT tables cannot be retrieved until DKMA restores the search. See DKMA notice. Denmark continues to report into EU EudraVigilance (panel above).

Medsafe (New Zealand)

VAERS (U.S., 2006–2024): 44,345 symptom mentions (9.07/100k doses). Largest share: Other / Unclassified (34%), Injection-site / Local reaction (25%), General / Systemic (non-local) (10%). Canada Vigilance (CV Online extract): 23,516 reaction mentions in 7,886 unique reports (33.7% serious (2,658 of 7,886 reports)). Largest share: General / Systemic (non-local) (27%), Injection-site / Local reaction (16%), Psychiatric / Neuropsychiatric (15%). JADER (PMDA public CSV extract): 2,059 reaction mentions in 1,232 unique reports (3.9% serious (48 of 1,232 reports)). Largest share: Other / Unclassified (27%), Respiratory (23%), General / Systemic (non-local) (17%). EudraVigilance (EU DAP export): 32,489 individual cases (up to 28/06/2026). Reaction SOC categories were not exported in the local DAP workbooks — case count only. VigiAccess (WHO): 647,774 reaction-term mentions · search: DTP. Largest share: Injection-site / Local reaction (26%), General / Systemic (non-local) (20%), Other / Unclassified (12%). Lareb (Netherlands): 8,831 reaction-term mentions · search: diphtheria tetanus pertussis vaccine. Largest share: General / Systemic (non-local) (27%), Injection-site / Local reaction (21%), Neurological (15%). DAEN (Australia): 64,516 reaction-term mentions · search: pertussis. Largest share: Injection-site / Local reaction (24%), Other / Unclassified (14%), General / Systemic (non-local) (13%). Medsafe (New Zealand): 4,021 reaction-term mentions · search: DTP. Largest share: Gastrointestinal (51%), Other / Unclassified (25%), Cardiac / Cardiovascular (9%). Cross-database note: All systems are passive and unverified; reporting rates are not directly comparable across countries (different populations, reporting incentives, and lack of dose denominators for Canada/Japan/EU). top VAERS: Other / Unclassified; top Canada Vigilance: General / Systemic (non-local); top JADER: Other / Unclassified. SurVigilance note: VigiAccess, Lareb, DAEN, DMA, and Medsafe counts are live-scraped MedDRA PT mention totals (not deduplicated individual cases). Data via SurVigilance (GPL-3.0; pip install SurVigilance). Category assignment uses keyword matching on reported reaction terms — approximate and exploratory. Neither database establishes causality.

Compare AE patterns across all vaccines →

Pharmacovigilance Lot Signal Detection — Hypothesis-Generating Only

Multi-system context below. VAERS (U.S.) supports lot-level volume z-scores and seriousness flags by product and lot (2006–2024). Each lot links to a summary with report count, seriousness %, adverse-event pie chart, U.S. state map, and timeline. A signal flag means a statistical threshold was exceeded — not that a lot is unsafe. Full dashboard →

VAERS flags: VOL high report volume (z ≥ 3) · BURST clustered in <90 days · SER serious reports >50%. Lot numbers are voluntary/incomplete in VAERS. Location data is U.S. state only (no postal codes in the public extract).

VAERS (United States) — all lots by product

25,253 reports with usable lot across 2,363 lots · 327 flagged

Loading lot tables…

Other Pharmacovigilance Systems

Lot-level analysis is only possible where reporters supply batch/lot numbers in the public extract. Canada Vigilance, JADER (PMDA, Japan), and most other national systems publish product-level spontaneous reports without lot fields.

Canada Vigilance (Health Canada)

7,886 unique reports · 23,516 reaction mentions · 33.7% serious (2,658 of 7,886 reports). Top categories: General / Systemic (non-local) (27%), Injection-site / Local reaction (16%), Psychiatric / Neuropsychiatric (15%).

Canada Vigilance spontaneous reports are unverified temporal associations. The public CV Online data extract does not include lot or batch numbers, so lot-level signal detection is not possible for this system — only product-level reaction patterns are shown here. No Canadian dose denominators are available. Extract 2026-03-31.

Search Canada Vigilance →

JADER (PMDA, Japan)

1,232 unique reports · 2,059 reaction mentions · 3.9% serious (48 of 1,232 reports). Top categories: Other / Unclassified (27%), Respiratory (23%), General / Systemic (non-local) (17%).

JADER (Japanese Adverse Drug Event Report database) spontaneous reports are unverified temporal associations; PMDA has not assessed causality per case. The public CSV extract does not include lot or batch numbers, so lot-level signal detection is not possible — only product-level reaction patterns are shown here. Reaction terms in source data use MedDRA/J Preferred Terms. JADER CSV extract pmdacasereport202606 (2026-06). JADER reference (PDF)

Search JADER / PMDA adverse reactions →

EudraVigilance (EU)

32,489 individual cases (up to 28/06/2026) · DIPHTHERIA, TETANUS AND PERTUSSIS (ACELLULAR, COMPONENT) VACCINE (ADSORBED). Reaction SOC breakdown not included in this DAP export.

EudraVigilance spontaneous reports are unverified temporal associations. The local EudraVigilance DAP workbooks provide individual-case counts from adrreports.eu; exported Reaction SOC filters were not set, so reaction-category charts are unavailable from this extract. Lot/batch numbers are not in public line listings.

Search EudraVigilance →

VigiAccess (WHO)

647,774 MedDRA PT mentions · search: DTP. Top categories: Injection-site / Local reaction (26%), General / Systemic (non-local) (20%), Other / Unclassified (12%).

Live-scraped public portal data via SurVigilance (GPL-3.0). Counts are reaction-term mentions, not deduplicated individual cases. No lot/batch field.

Search VigiAccess (WHO) →

Lareb (Netherlands)

8,831 MedDRA PT mentions · search: diphtheria tetanus pertussis vaccine. Top categories: General / Systemic (non-local) (27%), Injection-site / Local reaction (21%), Neurological (15%).

Live-scraped public portal data via SurVigilance (GPL-3.0). Counts are reaction-term mentions, not deduplicated individual cases. No lot/batch field.

Search Lareb (Netherlands) →

DAEN (Australia)

64,516 MedDRA PT mentions · search: pertussis. Top categories: Injection-site / Local reaction (24%), Other / Unclassified (14%), General / Systemic (non-local) (13%).

Live-scraped public portal data via SurVigilance (GPL-3.0). Counts are reaction-term mentions, not deduplicated individual cases. No lot/batch field.

Search DAEN (Australia) →

System	Region	Lot data
VAERS	United States	Lot data
Canada Vigilance	Canada	No public lot field
JADER (PMDA, Japan)	Japan	No public lot field
Lareb (Netherlands)	Netherlands	No public lot field
EudraVigilance	European Union	No public lot field
VigiAccess (WHO)	Global	No public lot field
Yellow Card (UK)	United Kingdom	No public lot field
DAEN (Australia)	Australia	No public lot field

All global data sources → · Data schemas →

Active Pharmacovigilance (Defined-Population Surveillance)

Curated findings for DTaP / Tdap from active systems (not VAERS). Page inventory last reviewed: 2026-07-10.

ⓘ Active vs. passive — why this pane is separate

The VAERS / multi-system charts above are passive surveillance: spontaneous, unverified reports without a fixed denominator. Active surveillance starts from a defined, enumerated population (EHR/claims or structured post-vaccination surveys), applies pre-specified statistical tests, and asks whether an outcome occurs more often than expected in a risk window versus a comparison window or group. These are not two flavors of the same evidence — active findings are the harder tier that can confirm, refute, or leave under investigation a signal first hinted in passive data. Do not add VAERS report counts to active incidence rates.

○ No signal detected ◐ Signal under investigation ◑ Investigated — not confirmed ● Signal confirmed (true association) – Not currently under active surveillance

CDC Vaccine Safety Datalink (VSD)

Outcome: Selected serious outcomes (e.g., encephalopathy historically studied; modern acellular products)

Tier 2 ○ No signal detected

Acellular pertussis vaccines were adopted largely to reduce reactogenicity versus whole-cell products. VSD and related systems continue to monitor DTaP/Tdap; no new confirmed rare serious risk on the order of rotavirus intussusception or COVID myocarditis has redefined routine use. Maternal Tdap safety has been a focus of dedicated studies.

Population

Infants/children (DTaP) and adolescents/adults (Tdap) at VSD sites

Risk interval

Study-specific

Comparison

Control intervals

Evaluation period

Decades of post-licensure active work; acellular era since 1990s–2000s

Method

Observational studies and RCA for combination/schedule questions

Sources: CDC VSD

Record last reviewed: 2026-07-10

Update cadence: Tier 1: check AusVaxSafety monthly when public pages update. Tier 2/3: quarterly review around ACIP meetings and PubMed/MMWR; set lastReviewed per record. Source tiers: Tier 1 = public near-real-time dashboards (e.g. AusVaxSafety); Tier 2 = VSD / Sentinel / PRAC-type findings released via ACIP slides, MMWR, or papers (no public VSD raw dashboard); Tier 3 = regulator label/safety communications. Detecting a signal and later classifying it as not confirmed is normal system behavior — not an anomaly to hide or amplify.

4. Documented Adverse Events — Evidence of Association

Rank-aggregated VAERS signal detection (rankv)

The table below lists vaccine–event pairs that were detected as disproportionality signals by all four base methods used in rankv (GPS, PRR, ROR, BCPNN) on multi-decade VAERS data, then ordered by rank aggregation (Borda average rank; related to the Spearman/GA top-list approach in the rankv paper).

Agg. rank	VAERS product	Preferred term (event)	N	Method ranks (GPS / PRR / ROR / BCPNN)
26	DTAP + IPV + HIB (PENTACEL)	Post-tussive vomiting clinical-coded PT · published top-25	109	GPS rank 124 (EBGM=11.67); PRR rank 23 (PRR=196.1497); ROR rank 22 (ROR=197.0205); BCPNN rank 16 (IC_LB=5.2113)
57	DTAP + IPV + HIB (PENTACEL)	Product preparation issue clinical-coded PT	109	GPS rank 98 (EBGM=16.27); PRR rank 83 (PRR=60.4141); ROR rank 83 (ROR=60.6792); BCPNN rank 30 (IC_LB=4.6279)
59	DTAP + IPV + HIB (PENTACEL)	Pertussis clinical-coded PT	166	GPS rank 132 (EBGM=9.82); PRR rank 74 (PRR=63.8936); ROR rank 74 (ROR=64.322); BCPNN rank 23 (IC_LB=4.8729)
175	DTAP + IPV + HIB (PENTACEL)	Product preparation error clinical-coded PT	77	GPS rank 157 (EBGM=9.05); PRR rank 189 (PRR=19.2938); ROR rank 190 (ROR=19.3514); BCPNN rank 146 (IC_LB=3.4714)
187	DTAP + IPV + HIB (PENTACEL)	Polymerase chain reaction clinical-coded PT	173	GPS rank 236 (EBGM=6.58); PRR rank 183 (PRR=18.8902); ROR rank 184 (ROR=19.0172); BCPNN rank 103 (IC_LB=3.7081)
238	DTAP (ACEL-IMUNE)	Gastrointestinal haemorrhage clinical-coded PT	32	GPS rank 270 (EBGM=7.39); PRR rank 198 (PRR=20.1312); ROR rank 200 (ROR=20.1924); BCPNN rank 203 (IC_LB=3.09)
291	TDAP (ADACEL)	Bordetella test positive clinical-coded PT	33	GPS rank 300 (EBGM=6.84); PRR rank 268 (PRR=10.4928); ROR rank 270 (ROR=10.4965); BCPNN rank 293 (IC_LB=2.2354)
305	TDAP (ADACEL)	Pertussis clinical-coded PT	56	GPS rank 274 (EBGM=6.65); PRR rank 307 (PRR=4.6599); ROR rank 307 (ROR=4.6623); BCPNN rank 308 (IC_LB=1.604)
92	DTAP + IPV (QUADRACEL)	Product administered to patient of inappropriate age admin/quality term	36	GPS rank 80 (EBGM=21.54); PRR rank 120 (PRR=41.0492); ROR rank 119 (ROR=41.7784); BCPNN rank 92 (IC_LB=3.788)
144	DTAP + IPV + HIB (PENTACEL)	Incorrect product formulation administered admin/quality term	61	GPS rank 115 (EBGM=14.19); PRR rank 171 (PRR=22.8444); ROR rank 171 (ROR=22.8989); BCPNN rank 132 (IC_LB=3.5244)
145	DTAP + IPV (QUADRACEL)	Wrong product administered admin/quality term	23	GPS rank 110 (EBGM=18.96); PRR rank 147 (PRR=32.2098); ROR rank 146 (ROR=32.5706); BCPNN rank 186 (IC_LB=3.1743)

Showing up to 15 pairs for this page (clinical-coded terms listed first). Full processed tables: rankv_signals.json.

Methods combined: BCPNN (IC), GPS/EBGM, PRR, ROR — then rank aggregation.
Data: ~30 years of public VAERS (rankv processed tables).
Origin: precisionFDA “Gaining New Insights by Detecting Adverse Event Anomalies” challenge solution.
Caveat: Disproportionality signals are statistical associations in spontaneous reports. They do not establish causality, incidence, or product defect. Many top pairs reflect administration/product-use coding rather than clinical injury.

Source: nanx.me/rankv · Code: github.com/nanxstats/rankv (MIT) · Built: 2026-07-30.

▶ Strong Evidence of Causal Association

Injection site reactions (pain, swelling, erythema): Very common. Extensive limb swelling (2–6%) with booster doses—self-limited. Strong
Fever (infants): ~15–30% with DTaP; lower than DTwP (40–60%). Strong
Febrile seizures: Small increased risk in the 0–1 day post-vaccination window (~1 per 15,000–25,000 doses), particularly with concomitant vaccines. Strong
Crying/inconsolability (infants): Common (10–30%). Self-limited (1–2 days). Strong
Hypotonic-hyporesponsive episode (HHE): Rare (~1–2 per 100,000 DTaP doses). Self-limited; does not cause long-term sequelae. Strong
Anaphylaxis: ~1–3 per million doses. Attributable to vaccine components. Strong
Shoulder Injury Related to Vaccine Administration (SIRVA): Bursitis/tendonitis from improper injection technique (too high on the deltoid). Not antigen-specific; procedure-related. Strong

▶ Moderate or Preliminary Evidence

Guillain-Barré Syndrome (GBS): IOM deemed evidence inadequate. Some tetanus toxoid studies suggest a possible very small increase, not consistently replicated. VSD rapid cycle analysis has not found a significant signal. Limited

▶ Published Evidence Does Not Support a Causal Association

SIDS: Multiple large studies; no association. IOM (2003) rejected causality. No Association
Autism: No association. IOM (2012) rejected causality. No Association
Encephalopathy: Thought to be associated with DTwP in rare cases; large studies of DTaP have not found an association. IOM (2012) favored rejection for DTaP and encephalopathy. No Association
Adverse pregnancy outcomes (Tdap): Multiple VSD and registry studies; no increased risk. No Association

5. Disease Prevention Benefits

Pre-Vaccine vs. Post-Vaccine Era (United States)

Metric	Pre-Vaccine Era	Post-Vaccine Era
Diphtheria cases (annual)	~200,000 (1920s); ~15,000 deaths/year	<5 cases/year since 2000; last U.S. death 2003
Tetanus cases (annual)	~500–600 (1940s)	~30/year; nearly all unvaccinated
Pertussis cases (annual)	~200,000 (pre-1940s)	~10,000–50,000 (post-DTaP era, with cyclical peaks); resurgence in the 2010s attributed to waning DTaP immunity
Pertussis infant mortality	~5,000–7,000 deaths/year	~10–20 deaths/year (primarily infants <3 months too young for vaccination; maternal Tdap has reduced this further)

Source: CDC Pink Book; MMWR surveillance summaries.

Key Observations

Diphtheria and tetanus: Near-elimination in the U.S., demonstrating high and durable vaccine effectiveness.
Pertussis resurgence: The switch from DTwP to DTaP reduced reactogenicity but may have reduced durability of protection. A 2012 Washington State epidemic (~5,000 cases) and a 2014 California epidemic (~11,000 cases) occurred in highly vaccinated populations, documenting waning DTaP immunity. Adolescent Tdap boosters and maternal Tdap are strategies to address this.
Maternal Tdap effectiveness: Maternal Tdap during pregnancy has been shown to prevent ~78–91% of pertussis cases in infants <2 months of age (the highest-risk population), according to multiple observational studies (Amirthalingam et al., UK, 2014; Skoff et al., U.S., 2017).

Disease Burden Over Time

Reported U.S. disease burden by year. The dashed vertical line marks vaccine introduction. Hover or tap data points for values; use arrow keys when a chart has focus.

ⓘ About these charts: These are accessible SVG line charts with keyboard navigation, hover tooltips, and an underlying data table (expand below). The dashed vertical line marks the year of vaccine introduction. Reported cases undercount true incidence; case definitions, reporting practices, and diagnostic methods have changed over time. See Section 5 for additional context and pre-vs-post era comparisons.

7. Evidence Summary

Overall Assessment

DTP vaccines have been in use for >70 years. The safety profile of the current DTaP/Tdap products is well-characterized for common adverse events and extensively studied for rare outcomes. The primary evidence gap is the durability of pertussis protection, which post-licensure data have shown to be shorter than initially expected. Injection site and fever-related reactions are common but self-limited. Serious adverse events (anaphylaxis, febrile seizures, HHE) are rare and well-characterized.

Domain	Evidence Grade	Key Finding
Diphtheria/tetanus effectiveness	Strong	Near-elimination; durable immunity
Pertussis effectiveness (initial)	Strong	~80–85% effective first 1–2 years
Pertussis durability (waning)	Strong	Significant waning by 3–5 years post-vaccination
Maternal Tdap for infant protection	Strong	~78–91% effective in preventing infant pertussis
Febrile seizures	Strong	~1 per 15,000–25,000 doses; well-characterized
GBS	Limited	Inadequate data; no consistent signal
SIDS	No Association	Multiple large studies; no association

8. International Surveillance & Global Data

Quick links to public pharmacovigilance databases and trial registries relevant to DTaP/Tdap Vaccine. Reporting counts do not establish causality.

Note: Spontaneous reports are unverified observations. Compare with epidemiological studies in Sections 3–6 before drawing conclusions.

9. Curated Adverse Event Literature

Curated peer-reviewed literature linking specific adverse events to DTaP/Tdap Vaccine. Each entry is a case report, case series, or related safety publication identified via PubMed. Expand Search PubMed for additional literature below to run custom queries.

Disclaimer: Published reports describe observations and associations; they do not establish population incidence or causality.

Common questions

How long do DTaP/Tdap vaccine side effects last?

Most reported DTaP/Tdap vaccine reactions are short-lived: injection-site soreness, tiredness, and low-grade fever that typically begin within a day or two and resolve within a few days. Longer-lasting or more serious events are rarer and are the ones tracked in the post-licensure surveillance and documented adverse-event sections of this page, with report counts that are not incidence rates. Anything severe or persisting beyond a week warrants medical review.

Is the DTaP/Tdap vaccine given to adults, and are side effects different in adults?

Whether the DTaP/Tdap vaccine is recommended for adults depends on the vaccine and the person's risk factors; the schedule and product sections above describe the licensed indications and age groups. Reporting patterns in adults can differ from children, so this page's VAERS and international database breakdowns should be read with the reporting population in mind. Check the current CDC/ACIP adult schedule and the product's prescribing information for adult dosing.

10. Key References

IOM. Adverse Effects of Vaccines: Evidence and Causality. National Academies Press; 2012. nationalacademies.org
CDC. Epidemiology and Prevention of Vaccine-Preventable Diseases (Pink Book) — Diphtheria, Tetanus, Pertussis chapters. cdc.gov/pinkbook
Kharbanda EO, et al. Safety of Tdap vaccine in pregnant women. JAMA. 2014;312(18):1897–1904. DOI: 10.1001/jama.2014.14825
Skoff TH, et al. Impact of the US maternal Tdap vaccination program. Clin Infect Dis. 2017;65(12):1977–1983.
Amirthalingam G, et al. Effectiveness of maternal pertussis vaccination in England. The Lancet. 2014;384(9953):1521–1528.
CDC. Vaccine Safety Datalink (VSD). cdc.gov/vaccine-safety/about/vsd.html
CDC/FDA. VAERS. vaers.hhs.gov
CDC. 2025 Child & Adolescent Immunization Schedule. cdc.gov/vaccines/hcp/imz-schedules

Evidence state

1. Basic Information

Diseases Protected Against

CDC Recommended Schedule (United States, 2025)

Licensed Products (U.S.)

Licensed DTaP/Tdap vaccine products

Ingredients (Package Insert)

Antigens

Adjuvants

Preservatives

Excipients & residuals

Antigens

Adjuvants

Preservatives

Excipients & residuals

Causality assessment & potential mechanisms

2. Pre-Licensure Clinical Trial Data

Licensure trial design (ICAN / OpenVAERS)

Historical Context: DTwP to DTaP Transition

DTaP Pre-Licensure Trials (Daptacel / Infanrix)

Tdap Pre-Licensure Trials (Adacel / Boostrix, 2005)

Most Common Adverse Reactions

Key Limitations

3. Post-Licensure Safety Data

Vaccine Safety Datalink (VSD)

VAERS

Major Independent Reviews

VAERS reports per million doses

What controlled safety studies found

Benefit and risk on the same scale (per million)

Serious outcomes of the disease (per million cases)

Trials, timing and other data sources

When do reported events start? (time to onset)

VAERS Reporting Data — Halma & Varon (2025), DARE-SAFE

Tdap — Additional VAERS Data (DARE-SAFE 2025)

Passive Surveillance: AE Type Breakdown (Multi-System)

VAERS (United States)

Canada Vigilance (Canada)

JADER (PMDA, Japan)

EudraVigilance (EU)

SurVigilance: VigiAccess · Lareb · DAEN · DMA · Medsafe

VigiAccess (WHO)

Lareb (Netherlands)

DAEN (Australia)

DMA (Denmark)

Medsafe (New Zealand)

Pharmacovigilance Lot Signal Detection — Hypothesis-Generating Only

Other Pharmacovigilance Systems

Canada Vigilance (Health Canada)

JADER (PMDA, Japan)

EudraVigilance (EU)

VigiAccess (WHO)

Lareb (Netherlands)

DAEN (Australia)

Active Pharmacovigilance (Defined-Population Surveillance)

CDC Vaccine Safety Datalink (VSD)

4. Documented Adverse Events — Evidence of Association

Rank-aggregated VAERS signal detection (rankv)

▶ Strong Evidence of Causal Association

▶ Moderate or Preliminary Evidence

▶ Published Evidence Does Not Support a Causal Association

5. Disease Prevention Benefits

Pre-Vaccine vs. Post-Vaccine Era (United States)

Key Observations

Disease Burden Over Time

7. Evidence Summary

Overall Assessment

8. International Surveillance & Global Data

9. Curated Adverse Event Literature

Common questions

How long do DTaP/Tdap vaccine side effects last?

Is the DTaP/Tdap vaccine given to adults, and are side effects different in adults?

10. Key References

Which Program Covers My Vaccine?

Next-Gen Pipeline & Clinical Candidates

VAXELIS

Diphtheria，Tetanus and Acellular Pertussis Combined Vaccine，DTaP

23-valent Pneumococcal Polysaccharide Vaccine (PPV23)

dTpa

dTpa vaccine