BCG abscess may signal active TB
From Dr Sandy Moffitt
GP and associate specialist
Leeds TB clinic
Case three of the child presentations (Clinical, 23 March) shows a typical BCG abscess but one would expect to see this after considerably longer than three days following immunisation. Most cases referred to our clinic are around six to 12 weeks after immunisation.
It should also have been made clear that the child should be fully assessed by an appropriate specialist. A BCG abscess may for instance be an indication of active TB in a child. Now that tuberculin testing is not performed prior to BCG in children under six years, an abnormal BCG reaction should be referred.
Persistence of live BCG organisms may indicate an immune problem such as interleukin 12 deficiency.
There is also a suspicion that the new BCG vaccine now supplied from Denmark is causing more reactions than previously. A yellow card should be completed and the person who performed the BCG informed.
But significant abscesses are rare and most BCG reactions settle with watchful waiting, leaving the site open and only using antibiotics if there is definite evidence of secondary bacterial infection with, for instance, staph.
Author replies: Dr Moffitt is correct. The abscess developed three months after vaccination.