Examining New Methods For Screening Volunteers For HIV Vaccine
Toronto's Globe and Mail on Thursday examined efforts to develop new measurements for screening the blood of volunteers in Africa for vaccine trials for HIV/AIDS and other infectious diseases, such as malaria and tuberculosis.
According to the Globe and Mail, researchers in Africa typically have used "reference ranges" -- or "normal" levels of components of a person's blood -- based on North American and European standards. However, a recently released study by the International AIDS Vaccine Initiative, the U.S. Military HIV Research Program and CDC found that Africans have different levels of white blood cells and other blood components that might categorize them as unhealthy by the Western measurements, even though they are considered healthy in their communities. For the study, researchers over a two-year period screened 5,500 clinically healthy, HIV-negative volunteers at about 12 sites across Africa for blood chemistry, and kidney and liver function to develop new reference ranges.
According to the findings, adults in Kenya, Rwanda, Uganda and Zambia have some differences from the Western measurements, including lower levels of lymphocytes, red blood cells and neutrophils, or cells that attack unknown objects. The participants also had increased levels of eosionphils, which protect against infection by parasites, compared with Western standards. According to the Globe and Mail, genetic and environmental factors account for the differences. Africans are more likely to have parasites, or anemia, or some level of malaria exposure, compared with people in the West, Pat Fast, director of medical affairs for IAVI, said.
The new reference ranges could be "particularly relevant to AIDS treatment," the Globe and Mail reports. HIV-positive Africans typically are instructed to begin antiretroviral treatment when their CD+4 T-cell counts drop below 200, but if a normal range is already lower, treatment should start sooner, the Globe and Mail reports. "A small shift in that curve could really change when you start treatment," Fast said.
Researchers also will be able to use the results of the study to accurately monitor the health of clinical trial volunteers, and the results will give researchers a more accurate gauge of the efficacy of a treatment, according to the Globe and Mail. Fast said, "It's important ... to shift our locus to the countries we are trying to develop the vaccine for, to shift the way we think, the way we measure" (Nolen, Globe and Mail, 9/20).
Reprinted with permission from kaisernetwork.org. You can view the entire Kaiser Weekly Health Disparities Report, search the archives. The Kaiser Weekly Health Disparities Report is published for kaisernetwork.org, a free service of The Henry J. Kaiser Family Foundation. 2007 Advisory Board Company and Kaiser Family Foundation. All rights reserved.