Side Effects of Tdap Vaccine
The Tdap vaccine commonly causes mild local reactions (pain, redness, and swelling at the injection site) and mild systemic reactions (fever, drowsiness, fretfulness, and anorexia), but these are self-limited and can be safely managed with symptomatic treatment. 1
Common Side Effects
Local Reactions
- Pain at injection site (occurs in up to 64% of recipients) 2
- Redness (occurs in up to 52% of recipients) 2
- Swelling (occurs in up to 41% of recipients) 2
- Nodule formation - may be palpable at the injection site for several weeks 1
- Sterile abscesses - rare (6-10 events per million doses) 1
Mild Systemic Reactions
- Fever (occurs in up to 66% of recipients) 3
- Drowsiness/fatigue
- Fretfulness/irritability (occurs in up to 38% of recipients) 3
- Loss of appetite (occurs in up to 25% of recipients) 3
- Sleep disturbances (occurs in up to 20% of recipients) 3
- Vomiting (occurs in up to 8% of recipients) 3
Less Common but More Significant Side Effects
Moderate-to-Severe Systemic Events
- High fever (≥40.5°C/105°F) - occurs infrequently 1
- Persistent, inconsolable crying lasting ≥3 hours - occurs in approximately 8% of recipients 3
- Collapse (hypotonic-hyporesponsive episode) - rare 1
- Short-lived convulsions (usually febrile) - rare 1
Severe Adverse Events (Very Rare)
- Anaphylactic reactions - extremely rare but potentially serious 1
- Encephalopathy - defined as an acute, severe CNS disorder occurring within 7 days following vaccination 1
- Erythema nodosum - rare skin reaction reported in case reports 4
- Large injection site swelling (>100 mm) - rare 2
Risk Factors for Increased Side Effects
- Previous doses: Local reactions and fever are substantially higher with increasing numbers of doses 1
- Age: There is a significant increase in localized pain as age increases 3
- History of seizures: Children with personal or family history of seizures may have increased risk of post-vaccination seizures 1
Management of Side Effects
Preventive Measures
- Acetaminophen prophylaxis: For children with history of seizures or family history of convulsions, acetaminophen (15 mg/kg every 4 hours for 24 hours) should be given at the time of vaccination and continued to reduce the possibility of post-vaccination fever 1
Treatment of Side Effects
- Local reactions: Usually resolve spontaneously and require no specific treatment
- Fever and pain: Acetaminophen or ibuprofen as needed
- Persistent fever: Fever that does not begin until ≥24 hours after vaccination or persists for more than 24 hours should be evaluated for other causes 1
Important Considerations
Contraindications
- Immediate anaphylactic reaction to a previous dose 1
- Encephalopathy not attributable to another identifiable cause within 7 days of a previous dose 1
Precautions (not absolute contraindications)
- Temperature ≥40.5°C (≥105°F) within 48 hours of a previous dose
- Collapse or shock-like state within 48 hours of a previous dose
- Persistent, inconsolable crying lasting ≥3 hours within 48 hours of a previous dose
- Convulsions with or without fever occurring within 3 days of a previous dose 1
Safety in Special Populations
- Pregnancy: Studies have not shown increased risk for adverse outcomes when Tdap is administered during pregnancy 1
- Shortened intervals between doses: Studies suggest that Tdap can be safely administered at intervals of ≥18 months since a previous tetanus-diphtheria vaccine 5
Common Misconceptions About Contraindications
The following are NOT contraindications to Tdap vaccination 1:
- Mild soreness, redness, or swelling at previous vaccination site
- Low-grade fever or mild illness
- Current antimicrobial therapy
- Recent exposure to infectious disease
- Prematurity
- History of allergies or relatives with allergies
- Family history of seizures
- Family history of adverse events following vaccination