Introduction to BCG Vaccine

The Bacillus Calmette–Guérin (BCG) vaccine is a live attenuated vaccine primarily used to protect against tuberculosis (TB), especially severe forms like TB meningitis and miliary TB in young children. It was developed in the early 20th century by French bacteriologists Albert Calmette and Camille Guérin and is one of the most widely administered vaccines globally.

Close up of reaction of Bacillus Calmette Guerin (BCG) vaccination in an infant.

Main Purpose of the BCG Vaccine

The primary goal of the BCG vaccine is to provide early protection against tuberculosis caused by Mycobacterium tuberculosis. While it is not highly effective at preventing adult pulmonary TB, it significantly reduces the risk of life-threatening TB complications in children.

Indications

The BCG vaccine is recommended for:

• Newborns and infants in countries with high TB prevalence, such as Malaysia.
• Unvaccinated children or adults who are at risk of TB exposure (e.g., healthcare workers, travelers to high-risk regions).
• Patients preparing for immunosuppressive therapy (with medical advice).

In Malaysia, the vaccine is routinely given to newborns shortly after birth.

BCG Vaccine Policy in Malaysia

In Malaysia, BCG is part of the National Immunisation Programme (NIP), provided free of charge at all public hospitals and clinics under the Ministry of Health (MOH).

• At Birth: All newborns in government facilities are vaccinated within 24 hours, provided there are no contraindications.
• Catch-up Doses: Unvaccinated children under 5 may undergo a Mantoux test before receiving the BCG shot.
• Scar Checks: A scar check is usually conducted in Primary 1 (around age 7) during school health visits.

Common Side Effects & Timeline

BCG vaccination typically triggers a localized skin reaction. Here’s a typical timeline of what to expect:

• Week 1–2: A small red bump may appear at the injection site, often slightly firm and warm to the touch.
• Week 3–4: The bump may turn into a small pustule or ulcer, resembling a pimple (5–10mm diameter).
• Week 5–6: The ulcer might burst and release some clear or yellowish fluid. This is normal and should not be squeezed or sealed tightly.
• Week 6–10: The wound scabs and gradually heals on its own.
• Month 2–4: A round, pale scar is formed — an indication of successful immunisation.

Important: If the area shows signs of spreading redness, excessive pus, persistent fever, or the baby appears unwell, seek medical attention.

What Parents Should Take Note Of

• No squeezing or rubbing: Let the injection site heal naturally. Avoid any ointment unless prescribed.
• Expect a scar: A small round scar typically forms within 2–4 months.
• No booster needed: BCG is a one-time vaccine. Even if no scar appears, revaccination is not recommended.
• When to see a doctor: If the area becomes very swollen, leaks pus continuously, or if the baby has high fever or prolonged irritability.
• Delayed vaccination: Premature or sick babies might get their shot later, as assessed by doctors.

Conclusion

The BCG vaccine plays a vital role in protecting children from serious forms of tuberculosis. In Malaysia, it is routinely administered at birth. Parents are encouraged to understand its purpose, be aware of the normal healing process, and consult healthcare providers when in doubt.