9 and 10-year old children are receiving Epivir and AZT after being exposed to HIV
“Some students already have begun taking a combination of medicines – 100 milligrams of Retrovir (or AZT, an HIV treatment) and 150 milligrams of Epivir (an HIV and hepatitis treatment), in addition to a stomach protector – to prevent the onset of the virus. One poking victim, George Whitaker, 10, reported having felt dizzy from the medication, and another, Jonathan Rodriguez, also 10, said he had vomited after taking it.”

Although probably a good idea, the data supporting post-exposure prophylaxis is scarce. Most of the data comes from maternal-infant transmission of HIV:

The benefit of ZDV in reducing maternal-infant transmission of HIV from 25.5 to 8.3 percent in the AIDS Clinical Trial Group Protocol 076 suggests that ZDV could also have a beneficial role in PEP (post-exposure prophylaxis). In a case-control study of needlestick injuries, HCWs who received ZDV prophylaxis were at lower risk for HIV transmission (odds ratio 0.19).

The case-control study mentioned an odds ratio of 0.19, meaning those who received prophylaxis had a 1/5th chance of contracting HIV from a needlestick.

The recommended treatment course is 4 weeks, but the optimal duration has not been studied. HIV testing should be done at baseline, six weeks, twelve weeks and 6 months after the exposure. Side effects occur in 50 percent of patients and consist mostly of nausea and fatigue; headache, vomiting, and diarrhea.