20 Tuberculosis

20.7 Expected responses and adverse events following immunisation (AEFI)

20.7.1 Expected responses

Ninety to ninety-five percent of people vaccinated with BCG develop a local reaction, which may include shallow ulceration, followed by healing and scar formation within three months. A minor degree of adenitis developing in the weeks following immunisation should be regarded as normal, not a complication. It may take months to resolve. Suppurative adenitis may take months to resolve; usually no treatment is required.

20.7.2 Adverse events following immunisationTop

Adverse events following immunisation with BCG vary with age and vaccine strain and are summarised in Table 20.1.

Table 20.1: Age-specific estimated risks for complications after administration of BCG vaccine

Complication Incidence per 1 million vaccinations
  Age <1 year Age 1–20 years
Local subcutaneous abscess; regional lymphadenopathy 387 25
Musculoskeletal lesions 0.39–0.89 0.06
Multiple lymphadenitis; non-fatal disseminated lesions 0.31–0.39 0.36
Fatal disseminated lesions 0.19–1.56 0.06–0.72

Source: Lotte A, Wasz-Hockert O, Poisson N, et al. 1988. Second IUATLD study on complications induced by intradermal BCG-vaccination. Bulletin of the International Union against Tuberculosis and Lung Disease 63: 47–59.

The risk of BCG adverse reactions depends on many factors, including strain type, route of administration and the underlying immune state of the patient. Severe injection site reactions, large ulcers and abscesses can occur in individuals who are tuberculin positive. Special care is needed both in interpreting initial tuberculin skin results and in delivering the BCG vaccine.

Rarely, osteitis and osteomyelitis, lupoid and other types of skin disorders, and neurological disorders have been reported following BCG vaccination. Although rare, disseminated BCG disease is the most severe BCG vaccine complication occurring in immune-compromised people, such as children with primary immune deficiency. This needs rapid and aggressive treatment and has a high mortality.

Keloid scars at the injection site, although not uncommon, are largely avoidable. Some sites are more prone to keloid formation than others and vaccinators should adhere to the site recommended (mid-upper arm). Most experience has been with the upper arm site, and it is known that the risk of keloid formation increases greatly if the injection is given higher than the insertion of the deltoid muscle into the humerus.

Every effort should be made to recover and identify the causative organism from any lesions that constitute a serious complication.

Most local and regional adenopathy resulting from BCG vaccination will resolve spontaneously, and there is rarely a need for medical or surgical intervention. Treatment recommendations for local abscess formation and suppurative lymphadenitis remain controversial.24 If suppurative adenitis reactions persist for longer than three months, seek specialist opinion. However, anyone presenting with more widespread or distant disease needs referral to a specialist.

Abscesses and more serious complications should be reported to the local medical officer of health in the interests of quality control of the BCG vaccination technique, and to the Centre for Adverse Reactions Monitoring (CARM) (see ‘AEFI reporting process – notifying CARM’ in section 2.5). Information about adverse reactions to BCG vaccine reported in New Zealand can be found in the Suspected Medicine Adverse Reaction Search (SMARS) on the Medsafe website (