Childhood HIV Exposure: Prophylaxis or Hope?

There is no easy answer for parents whose child may have been exposed to HIV. Decisions to subject both child and parents to a 28-day course of prophylaxis must be made quickly, and most likely with incomplete information.

"You may well have to accept the risk of prophylaxis or no prophylaxis without full information," said Ellen Cooper, MD, professor of pediatrics at Boston University School of Medicine. "All you can do is help the family evaluate the relative risks based on what you do know."

Risk evaluation begins with the type of potential HIV exposure, Dr. Cooper explained. Blood or other fluids containing blood from a person with HIV are usually infective. Semen, vaginal secretions, and bodily fluids that do not contain blood are typically less infectious.

Intact skin usually presents a barrier adequate to prevent infection, but any kind of wound increases the risk. A deep tissue injury, for example, can increase the risk of infection by 15 times. Visible blood on a needle or other object causing a wound can increase the risk of infection by 6.2 times.

Kissing carries little to no risk of HIV infection, while oral sex is a relatively low-risk exposure, she continued. Receptive vaginal sex presents intermediate risk while receptive anal sex is a high-risk activity. Any kind of traumatic sexual activity that produces blood confers a very high risk of infection.

The risk of infection from sexual contact is generally related to age, Dr. Cooper said. "The younger the child, the more likely they are to acquire HIV after a single act of sex, consensual or not," she said. "It's physiological. Younger people generally have thinner, less resistant skin than adults."

Any decision to use prophylaxis also depends on the time since exposure. The earlier after exposure prophylaxis begins, the more likely it is to be effective, she explained. If more than 72 hours have passed since exposure, prophylaxis is not likely to have any significant protective effect.

A three-drug regimen that includes a protease inhibitor is generally recommended for postexposure prophylaxis. But the commonly used protease inhibitors, such as nelfinavir (Viracept) and lopinavir/ritonavir (Kaletra), produce severe diarrhea, nausea, and abdominal pain in nearly 100% of patients. A two-agent regimen using zidovudine (Retrovir) and lamivudine (Epivir) is more tolerable for many patients.