Are there side effects or contraindications for BCG vaccination?

The BCG vaccine may cause mild, localized reactions at the injection site. Serious side effects are uncommon. Certain individuals should not receive the vaccine due to specific health conditions or a weakened immune system.

Side Effects

Common (Normal) Side Effects

• Injection Site Reaction:
  • A small, red, tender lump develops at the injection site.
  • Within 2–4 weeks, it forms a blister or sore.
  • The sore scabs over and heals, leaving a small, flat, permanent scar.
• Swollen Lymph Nodes:
  Temporary swelling in the armpit on the same side as the injection may occur.
• Mild General Symptoms:
  Some people experience short-lived, flu-like symptoms such as mild fever or headache.

Uncommon and Rare Side Effects

• Abscess: A larger collection of pus may form at the injection site.
• Severe Ulceration: The sore may become unusually large or take longer to heal.
• Disseminated BCG Infection: In very rare cases, the vaccine may cause a serious, widespread infection, usually in those with severely weakened immune systems.
• Bone Inflammation (Osteitis/Osteomyelitis): Extremely rare inflammation of the bone.
• Keloid Scarring: Some individuals may develop raised or thickened scars at the injection site.

Contraindications

Because the BCG vaccine is a live vaccine, it should not be given to people with a weakened or suppressed immune system.

Do not receive the BCG vaccine if you:

• Have a weakened immune system due to:
  • HIV/AIDS
  • Congenital immunodeficiency
  • Leukemia, lymphoma, or other cancers
  • Chemotherapy, radiation therapy, or high-dose steroid treatment
• Are pregnant
• Have active tuberculosis or a positive TB skin test
• Are unwell with fever or a widespread skin infection
• Have had a severe allergic reaction to a previous BCG dose or its ingredients
• Have a family history of severe immunodeficiency
• Are a baby whose mother received immunosuppressive treatment during pregnancy

Special Precautions for Infants Exposed to HIV

• In areas with good HIV testing services, delay BCG vaccination for babies born to HIV-positive mothers until the baby’s HIV status is confirmed negative.
• Babies with confirmed or symptomatic HIV/AIDS should not receive the BCG vaccine.

Drug Interactions

• Certain immunosuppressant or antimicrobial medications can reduce the vaccine’s effectiveness.
• Avoid giving other injections in the same limb as the BCG vaccine for at least 3 months to prevent lymph node inflammation (lymphadenitis).