Universal BCG vaccination at birth in HIV-infected areas increases the risk of serious complications like disseminated BCG disease in HIV- infected infants because of their suppressed immune status, Dr. Anneke C. Hesseling and colleagues from South Africa explain in the January issue of the journal Vaccine.

The paucity of reports on disseminated BCG infection due to possible underreporting or lack of diagnostic facilities prompted Dr. Hesseling's team from the Desmond Tutu Tuberculosis Centre of Stellenbosch University, Tygerberg, to evaluate the prevalence of the disease among infants in the Western Cape area between 2002 and 2004.

Cases of disseminated BCG infection in infants were identified using hospital-based surveillance and confirmed by polymerase chain reaction. The population prevalence of disseminated BCG infection was then calculated using the mid-year projected population data and BCG vaccination rates, while the prevalence of congenital HIV infection was estimated using available data on mother-child HIV transmission rates.

Disseminated BCG was diagnosed in nine infants during the study period, seven of whom were HIV positive and showed signs of disease, the researchers report.

They estimated that the incidence of disseminated BCG among HIV-infected infants could range from139 to 350 per 100,000 vaccinated children under 1 year of age, depending on the mother-child HIV transmission rates. In comparison, the estimated incidence among HIV-negative infants was significantly lower at around 0.7 per 100,000 population during the study period, they report.

"There are not enough data on the potential benefits of BCG in infants born to HIV-infected mothers to weigh up the risk and benefit ratio of BCG vaccination in infants in settings with high HIV burden ," Dr. Hesseling told Reuters Health.

"One potential strategy, if good TB surveillance is in place and mothers are routinely screened for TB, is to delay BCG vaccination in HIV-exposed infants until their HIV status has been determined," Dr. Hesseling said. "This can readily be done at 6 weeks of age, through polymerase chain reaction. BCG can then safely be administered to uninfected infants."

Vaccine 2007;25:14-18.

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