Vaccine Contraindications
In some situations, vaccination may be contraindicated or require special precautions to further reduce the risk of adverse events.
For all vaccines
- In case of a mild illness or fever, postpone vaccination by 1–2 weeks.
- A severe allergy to a vaccine component or a severe allergic reaction after a prior dose is a contraindication to (re)vaccination. With mild allergic reactions (urticaria), vaccination may continue with precautions (e.g., antihistamine).
- With undefined, evolving neurologic disease (e.g., infantile spasms, uncontrolled epilepsy, progressive encephalopathy), vaccinate as soon as the neurologic status is clarified and stabilized.
Live-attenuated vaccines (MMR, varicella, yellow fever)
- Avoid during pregnancy (use contraception for 1 month after each dose).
- Contraindicated with immunodeficiency (cellular) or advanced HIV and during immunosuppressive therapy (e.g., prednisone ≥ 2 mg/kg/day or 20 mg/day for > 14 days).
- Wait at least 5 months after immunoglobulins or blood products.
Anaphylaxis
Anaphylaxis is a severe, systemic hypersensitivity reaction that can be life‑threatening. It is an exceptional complication of vaccination (≈ <1 per 100,000 doses) and may occur with any vaccine and in any patient.
- Observe each patient for 15 minutes after vaccination.
- Vaccinators must recognize early signs and have epinephrine and a protocol ready to initiate treatment immediately.
- Hospitalize for monitoring even if symptoms rapidly regress.
- Additives are more often implicated than the antigen itself; ask about prior immediate reactions.
- Most reactions occur within 15 minutes. Early severity is not predictive and death may occur within minutes.
Clinical criteria (Sampson et al., 2016) define three scenarios for diagnosis and early management — sensitivity 97% and specificity 82%.
Treatment: Epinephrine
Administer as early as possible, preferably intramuscularly. Recommendations from the French Society of Emergency Medicine (2016).
Dosing — Adults
- Subcutaneous: 0.3 mg (0.3 ml undiluted). Improvement typically in 3–5 min; a second dose may be given 10–15 min later if needed.
- Intramuscular: 0.5–1 mg (0.5–1 ml), repeat every 5 min if required.
- Intravenous: 0.1 mg after dilution (1 mg in 9 ml 0.9% NaCl) then 1 ml boluses of the diluted solution, repeated until hemodynamic recovery under close monitoring.
Dosing — Infants and children
I.M. or S.C.: 0.01 mg/kg
- < 2 years (≤ 12 kg): 0.05 to 0.1 mg (0.05 to 0.1 ml undiluted).
- 2–6 years (12–18 kg): 0.15 mg (0.15 ml undiluted).
- 6–12 years (18–33 kg): 0.2 mg (0.2 ml undiluted).
Resources
- https://www.infovac.ch/fr/faq/ contre-indications-vaccinales
- https://professionnels. vaccination-info-service.fr/ Aspects-pratiques/Acte- vaccinal/Declaration-d-un- effet-indesirable
- https://professionnels. vaccination-info-service.fr/ Aspects-pratiques/Allergies- et-autres-contre-indications/ Prise-en-charge-de-l- anaphylaxie
- https://www.who.int/vaccine_ safety/publications/aefi_ global_manual_Nov2015_FR.pdf? ua=1
