SITE: BCG vaccination must be administered strictly intradermally – this means into the top layer of the skin. Normally the vaccination is given into the side of the left upper arm at the level of the insertion of the deltoid muscle. This is the site recommended by the World Health Organisation (WHO) so that if an adult in later life isn’t certain or not whether they have had a BCG, health professionals can check the left upper arm to look for a scar. Sites higher on the arm and particularly the tip of the shoulder are more likely to leave keloid formation (raised, thickened scarring) and should be avoided. As a matter of preference, a few people will request administration of BCG vaccination into the thigh to prevent scar formation in a visible area such as the upper arm. There is no evidence to suggest that there is any difference in the effectiveness of BCG vaccine given at this site.
EFFECTIVENESS: In general, studies of the effectiveness of BCG vaccine have given widely varying results between countries and between studies. It seems that the vaccine is 70 to 80% effective against the most severe forms of the disease such as TB meningitis in children. It is less effective in preventing respiratory disease which is the more common form in adults.
AGE: There is little data on the protection afforded by BCG vaccine when this is given to adults aged 16 years or over and virtually no data for people aged 35 years or over. BCG is not usually recommended for people aged over 16 years unless the risk of exposure is great, for example: healthcare or laboratory workers at occupational risk or where vaccination is indicated for travel.
BCG should ideally be given at the same time as other live vaccines such as MMR. If live vaccines cannot be administered simultaneously a four week interval is recommended.
NO FURTHER IMMUNISATION SHOULD BE GIVEN IN THE LIMB USED FOR BCG IMMUNISATION FOR AT LEAST THREE MONTHS because of the risk of swelling of the nearby lymph glands (regional lymphadenitis).
Immunisation reaction and care of the immunisation site
- In the case of small babies who are in the middle of their routine NHS immunisation schedule as stated no further immunisation should be given in the limb used for the BCG immunisation for at least three months. All of the two month, three month and four month routine childhood vaccinations can be given in the opposite leg if one thigh has been used for BCG as long as they are given 2.5cm apart.
- The BCG injection initially leaves a small raised bump on the skin. This does not need to be covered after the journey home so remove the spot plaster as soon as possible. The white bump will fade and disappear over a few hours.
- Most people get some redness at the injection site followed by a local reaction which starts as a small lump two or more weeks after vaccination. This may ulcerate and then slowly subside over several weeks or months to heal leaving a small flat scar. There may also be a little enlargement of a regional lymph gland in the armpit or groin.
- It is not necessary to protect the site from becoming wet during washing and bathing. The ulcer should be encouraged to dry and abrasion (rubbing by tight clothes for example) should be avoided. Should any oozing occur a temporary dry dressing may be used until a scab forms.
- It is essential that air is not excluded. If absolutely essential, for example, to permit swimming, a waterproof dressing may be used but it should be applied only for a short period as it may delay healing and cause a larger scar.
- Individuals with severe local reactions (ulceration greater than 1cm or enlargement of a regional lymph node to greater than 1cm with or without ulceration, or abscess or drainage at the injection site) should be seen and referred to a chest physician or paediatrician for further investigation and management.