When does the BCG scab fall off? How to tell whether the BCG vaccination is successful?

BCG is a vaccine that the hospital will give to babies after they are born. Pustules and suppuration are normal reactions to successful vaccination. After that, scabs will form and fall off. So when will the scabs fall off after BCG vaccination? How do you know if the vaccination is successful?

When does the BCG scab fall off

BCG is a live attenuated bacteria vaccine. After vaccination, the attenuated bacteria can reproduce at the inoculation site, and a corresponding reaction caused by the biological activity of BCG may occur. Most recipients will experience local redness, swelling, papule-like infiltration and hard masses in about 2 weeks, which will gradually soften into white pustules and may rupture on their own (discharging some secretions) to form ulcers. Generally, they will heal and form scabs after 8 to 12 weeks. After the scab falls off, a depressed scar (cardiac scar) will form locally.

A very small number of recipients may experience slight enlargement of the ipsilateral axillary lymph nodes 4-12 weeks after vaccination, with a diameter of less than 10mm, which disappears after 4-8 weeks.

How to check whether BCG vaccination is successful

1. Observe with the naked eye whether there is a scar formed at the vaccination site. If the size is 3-5mm, the vaccination can be considered successful.

2. Go to the vaccination agency for a BCG test. This method is more scientific, but the child will suffer. Generally speaking, professional institutions also use the first method to make judgments. The second method is used only when the scar is too small.

Why can't you get BCG vaccination?

1. People who are suspected of having tuberculosis or suspected of being infected with tuberculosis should first undergo a tuberculin test to confirm that they are not infected with tuberculosis, that is, the tuberculin test is negative, before they can be vaccinated with BCG.

2. People with acute fever, skin diseases, severe eczema, chronic diseases, acute infectious diseases, premature babies or newborns weighing less than 2500 grams should not be vaccinated with BCG for the time being.

3. People with congenital or acquired immune deficiencies must not be vaccinated with BCG.