Great science writing
From an AP story about the 8 year old who stabbed many of her classmates with a used needle:
Although the authorities said the odds of the needle transmitting the virus to the other children were extremely low, the drugs would reduce the amount of the virus in their blood or slow the progress of the disease. The drugs do not cure H.I.V. infection or prevent transmission of the virus.This is completely wrong. The whole purpose of giving the medicines is to prevent infection. When someone, usually a health care worker but occassionally a situation like this or someone who has unprotected sex, consensual or not, has a potential exposure using anti-HIV meds can prevent establishment of infection
According to the article, one of the students jabbed with the needle tested HIV positive, which is itself odd. At age 8, the child was almost certainly infected perinatally, but disease should be evident by now. So the most likely explanation is that one of the classmates was known to be HIV positive.
The good news is that the risk on infection for these kids is very small. 1/300 at most, probably much less if the jab to the HIV positive kid didn't hit blood (and zero for the kids jabbed before that child).