By Sean Henahan, Access Excellence

WASHINGTON, D.C. (May 7, 1996)- New research suggests vaccines can be designed to suppress infection by the human immunodeficiency virus (HIV) in children, according to reports at the 1996 meeting of the American Pediatric Society and Society for Pediatric Research in Washington, D.C.

A year long study of three similar, genetically engineered vaccines showed they were safe in symptom-free, HIV-infected kids ranging in age from month to 18 years. In addition, the vaccines affected the way infection-fighting cells handle the virus, giving researchers hope that further studies will prove vaccines can alter the spread of HIV in the body.

"They may keep the virus from actively replicating," says John Lambert, M.D., a Johns Hopkins researcher and study coordinator for a national group of researchers from the NIH-sponsored Pediatric AIDS Clinical Trials Group. "We are also anxious to learn if lab results will translate into healthier, longer lives for children."

According to the National Institute of Allergy and Infectious Diseases, 1,300 to 2,000 children in the United States are infected each year with HIV. Most often, it is passed from mother to child before or during birth, and many children develop AIDS, the disease caused by HIV infection. Children with HIV suffer more infections than adults, they say. Growth and developmental are impaired when HIV assaults immature immune, nervous and organ systems.

The recombinant envelope vaccines used in this study were manufactured in three different labs and made from plant proteins and bacteria. Becoming infected with HIV from one of the vaccines is impossible, since it contains no human byproducts, says Lambert, an assistant professor of pediatrics and international health at Hopkins.

The vaccines contain a replica of HIV's outer shell (or envelope). In theory, the body recognizes the envelope as foreign and makes antibodies against it. Those antibodies not only go after the "impostor" virus, but the real one as well, protecting against HIV in two different ways. First, the antibodies block the ability of HIV to infect and kill T-lymphocytes. Second, they attack HIV floating in the bloodstream.

The study showed that all three vaccines succeeded in the first goal, proved by sampling cells after vaccine was administered at one-, two-, three-, four- and six-months intervals. Each time, the cells responded to a stimuli, indicating they "remembered" being helped by antibodies.

But future studies are needed to determine if enough antibodies are produced to fight HIV in the bloodstream, too, says Lambert.

Meanwhile, all of the 79 volunteers (39 percent boys, 61 percent girls) remained healthy, with no evidence of severe reaction, adverse immune response, opportunistic infection or increased HIV replication. All of the children were able to complete the study, conducted in 16 cities including Chicago, San Francisco, Los Angeles and Baltimore.

However, warns Lambert, because all of the children enrolled in the study were symptom-free, even the 21 patients who received placebo did not develop signs of worsening. "Thus, while this study shows us that therapeutic vaccination is safe in HIV-infected infants and children, we still don't know if the vaccines will give pediatric patients a better chance of survival in the long-run," he says.

The current standard of treatment for reducing the risk of maternal transmission of HIV involves treating the mother with the anti-retroviral compound zidovudine and related compounds. Several studies have confirmed that this significantly reduces prenatal and perinatal transmission to the baby.

The data in this report were presented on May 7 at the 1996 meeting of the American Pediatric Society and Society for Pediatric Research in Washington, D.C.

Related information on the Internet

Pre-natal HIV Predictor

JAMA HIV Info.

HIV Replication Primer

HIV Pathogenesis

YAHOO AIDS DIRECTORY