What are the concerns for pediatricians if the birth parent's HIV status is unknown (i.e. was not tested or refused the test?)

Although HIV status is known in the majority of pregnant people or a rapid HIV test is done during delivery, in a small number of newborns the birthing parent’s HIV status may not be known. In these situations, it is critical to do a rapid HIV test on the newborn as soon as possible after birth, since early prophylactic therapy for newborns with HIV exposure can still prevent infection in almost half of infants.