Black Africans in the United Kingdom who are infected with HIV tend to have lower levels of the virus in their blood compared with people from other ethnic groups who are at the same stage of disease, according to a small study in a recent issue of the Journal of Infectious Diseases (2001;183:1518-1521). Doctors use viral load to help predict how quickly a person's disease will progress to AIDS, and it is often an indicator for when to start drug treatment. "This has implications for using virus load in black Africans as an indicator for when to initiate or to change antiretroviral therapy, and it suggests that treatment may need to be initiated at a lower virus load for black Africans than for whites," wrote Dr. Jacky Saul, who conducted the study while at St. Thomas's Hospital in London, and colleagues. "If this [test] is accurate these findings suggest that virus load should be interpreted differently for different ethnic groups," the report said.

The researchers measured HIV levels and CD4+ counts in the blood of 322 patients who visited a clinic in London between May 1997 and February 1999. "Our results show that, for a given CD4+ cell count, black Africans present with a virus load lower than that of white patients," the authors noted. However, the authors also pointed out that the test they used to measure virus load may not be sensitive enough to measure the subtype of HIV that is most common in the sub-Saharan African patients in their study. Most HIV-positive black Africans in the UK are infected by HIV subtypes A and C, whereas white patients are predominantly infected by subtype B, according to the authors.

But Dr. Bob Bollinger, a Johns Hopkins University associate professor of infectious diseases who was not involved in the study, said its results are too preliminary to prompt doctors to change their current practice. He said the Africans may have had lower virus levels because they "could have been infected more recently," and he pointed out that a number of other studies have shown no difference in HIV levels between ethnic groups.

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