Lobar pneumonia is caused due to entry of the bacteria into the lung via the trachea and bronchus. Hence the lobe supplied by a particular bronchus is affected. It has better prognosis then other variety of Broncho pneumonia. TO prevent it from occurring again improve the feeding habits of your child. Ask him to eat in sitting position, slowly in small morsels and to maintain a few seconds gap between food and taking water or liquids with it. And yes Pneumonia can cause raise in white blood cell count and yes due to release of Inflammatory mediatiors it may cause vomiting along with fever. But if it as long as 3 weeks kindly consult a pediatrician once.