If she coughs, she is contagious.
Any kind of pneumonia can be contagious if the microorganisms (viruses or bacteria) are present in the mucus secretions. They are aerosolized through coughing and sneezing. Since the lungs become very wet in cases of pneumonia, there are plenty of contaminated secretions.
Infections deep down in the lungs (such as avian influenzas) are minimally contagious, since the viruses are not secreted into the mucus in the upper airways.
With bacterial pneumonia, treatment reduces the length of time the person is contagious.
Hillary was presumably diagnosed on Friday and prescribed antibiotics. By Sunday, she may or may not have still been contagious. However, she still appeared to have an active disease process going on--if we are to believe the pneumonia story--and thus, it is reasonable to suspect she would still be contagious. To make a long story short, that little girl should have been wearing a mask before they sent her running out to be a stage prop. And any areas that Hillary touched should have been disinfected (e.g. with hand sanitizer) right away.
Thank you, FRiend.