Heaf status 12 years after infant BCG immunization.

Uncertainty exists over the long-term influence of Heaf status and immunity of infant BCG immunization. BCG is offered to all Leeds Asian infants with uptake estimated at 86%. We have examined the effect of this immunization policy on the Heaf status of all 12- to 13-year-old children tested in the city in 1988. 6363 children (431 Asians) were eligible for Heaf testing of whom 5379 (366 Asians) were tested. 90 (25%) Asians and 4596 (92%) non-Asians had a Heaf grade 0-1 with no definite previous BCG and were, using current UK Department of Health recommendations, eligible for BCG immunization. With an annual incidence of tuberculosis in Asian children in Leeds of only 6 per 100,000 it is probable that most of the 75% of Asian children who did not require immunization had persisting immunity from their infant BCG rather than as a result of primary infection. We conclude that infant BCG immunization is effective at providing appropriate immunity, avoiding repeat BCG, in most children at age 12 years.