There are no studies as yet looking at the effect of ritonavir on the spread of HIV from mother to child. Ritonavir is approved for use in children ages 2-16 years old. Safety for children under two years of age has not been shown. Note that doses for children are linked to body weight. Side effects in children are similar to those seen in adults including diarrhea, nausea, vomiting and malaise.
Ritonavir comes in an oral solution for use in children.
The taste is not pleasant. Some ideas for reducing the taste of ritonavir include feeding the child peanut butter or a lifesaver to coat the mouth before giving the drug. Also, after the child takes the drug, something that tastes good like chocolate may help wash out the aftertaste of the liquid. This is because it's more difficult for the virus to mutate when viral load is extremely low or below the limit of detection. All PIs have at least some risk of cross-resistance to the other drugs in its class.