About an hour outside Livingstone, sits Simonga Clinic, the first of several clinics we will visit while in Zambia. Simonga clinic is busy already with under five day. Babies breastfeed while toddlers play with each other tugging on clothing, and scoping visitors out warily. A tiny girl in pink tries to drag Mom’s purse across the concrete floor to show a friend. She bursts into tears when Mom lifts the bag out of reach. Another toddler wanders over to the immunologist in our group and he waves repeatedly engaging, until she holds out her hand for a high five. Then he is suddenly…