Testing Times: The Importance of Identifying HIV Infections before It's Too Late
Harder, Ben, Science News
The 27-year-old woman had just delivered a healthy baby girl at Cook County Hospital in Chicago when obstetrician Julie B. Schmidt entered the maternity suite bearing bad news. Just an hour earlier, in the throes of labor, the young woman had consented to an HIV test. Now, Schmidt had the result. As gently as possible, the doctor told the mother she had the virus. The new information demanded immediate action: With the right course of drugs and a dose of luck, the newborn could be saved from infection.
Ideally, drug treatment for a pregnant, HIV-infected woman and her fetus begins months ahead of delivery. That regimen reduces the chance of mother-to-child transmission to less than 1 percent. Without a diagnosis or antiviral drugs, that risk can soar to 25 percent.
The physicians at Cook County Hospital capitalized on their eleventh-hour discovery and gave the newborn drugs immediately. The baby escaped infection.
Medicine may have helped avert one tragedy that day, but such close calls underscore the need to discover more HIV infections earlier, and not just among pregnant women. People who are diagnosed with HIV infection soon after they acquire it get the most benefit from state-of-the-art therapies that can extend their lives by years.
The rest miss out on life-sustaining treatments and are at high risk of spreading the virus. An estimated 180,000 to 280,000 people in the United States--about one-quarter of those infected with HIV--don't know it, and they cause about two-thirds of new infections, estimates Robert S. Janssen, who works on HIV and AIDS prevention at the Centers for Disease Control and Prevention (CDC) in Atlanta.
By and large, Janssen says, "when people learn that they're infected, they take steps to reduce the risk of transmitting to partners." That explains why the government's current HIV-prevention initiative aims to shorten the time it takes to identify people infected with the virus.
A new rapid blood test, which helped diagnose Schmidt's patient, is playing a central role in that effort. The test is being applied by a makeshift militia of researchers, health-care providers, and community-based health workers, trained to use it.
Some HIV fighters caution that hurried and imperfect implementation of rapid testing could mean that some people will get life-shattering information but won't receive the life-saving care that should follow.
To help make decisions about whom to test, researchers are working to identify groups of people that are likely to have high proportions of undiagnosed HIV cases. Schmidt's patient belonged to three of those groups: She was poor, African American, and presumably infected through heterosexual contact.
RAPID RESULTS If Schmidt's patient had received standard prenatal care, she might have been diagnosed months earlier. To help head off cases of mother-to-child HIV transmission, many obstetricians routinely offer HIV tests to women early in their pregnancies. Some states require such tests. But Schmidt's patient, like many expectant mothers from inner cities, showed up for care only when she was in labor.
That's one situation where rapid testing is invaluable, says Mardge H. Cohen of the Cook County Bureau of Health Services in Chicago. Last November, the Food and Drug Administration approved the OraQuick Rapid HIV-1 Antibody Test, which is manufactured by Abbott Laboratories of Abbott Park, Ill. Cohen runs the Chicago arm of a CDC-funded nationwide study that provided OraQuick kits to Schmidt's staff.
"The case for rapid testing is pretty clear in labor and delivery," says Cohen. Of hundreds of pregnant women to whom the investigators offered rapid HIV tests at four Chicago hospitals, including Cook County Hospital, nearly 80 percent accepted. About 1 percent have tested positive for HIV, and most got their results within an hour, Cohen and her colleagues report in the Sept. …