HHS Secretary Louis W. Sullivan, M.D., today announced that the Food and Drug Administration has licensed the first combination test kit for detecting antibodies to both human immunodeficiency virus type 1, or HIV-1, and a second but far less common cause of AIDS -- human immunodeficiency virus type 2, or HIV-2.
Dr. Sullivan said, "Although antibody test kits for the separate detection of these AIDS viruses are already licensed, the new combination test kit can detect antibodies for both viruses in a single test. This ability could significantly streamline testing procedures for the blood industry and other institutions engaged in high volume screening, and could further improve the overall safety of the blood supply."
Antibody tests for HIV-1 were licensed by FDA in March 1985 and are now in universal use among the nation's blood establishments. Their use has dramatically reduced the risk of HIV-1 infection through the blood supply. It is currently estimated that the risk of contracting AIDS from a blood transfusion has dropped by more than 99% from 1983 to 1991.
An antibody test for HIV-2 was licensed in April 1990. The health consequences and routes of transmission for HIV-2 infection are similar to those of HIV-1, but the occurrence of HIV-2 in this country is extremely rare. The first confirmed case of AIDS caused by HIV-2 infection in the United States was reported in 1987.
FDA Commissioner David A. Kessler, M.D., noted that HIV-2 antibody testing has not been required by FDA of all blood establishments because the virus does not currently pose a significant risk to the blood supply. Commissioner Kessler said, "Relatively few blood banks have instituted HIV-2 testing because of the additional procedural and resource burdens it would place on them and the current absence of significant risk. A combination test will overcome many of the procedural problems, and may encourage more widespread testing for this virus."
The new test uses the enzyme-linked immunosorbent test method, or ELISA, format, the same basic type used in separate test kits for detecting HIV-1 and HIV-2 antibodies. A "reactive" reading with the screening test means that an individual may have been exposed to either HIV-1 or HIV-2 and that his or her body is producing antibodies in response to the infection.
In order to specify which virus is the source of infection, and to check against the possibility of false positives inherent in all ELISA tests, FDA recommends that reactive results to the combination test be validated with additional, more specific tests.
The combination test will be manufactured by Genetics Systems Corporation of Seattle, Wash. -- the company that manufactures the only licensed HIV-2 antibody test.