The Pneumococcal vaccine will be recommended for your child at their 2-month checkup. It is designed to protect against a particular bacteria called Streptococcus pneumoniae, sometimes called Pneumococcus, or PC for short. It’s a very common bacteria, especially because there are many different strains of it floating around at any given time. Most people get pneumococcus infections and deal with them just fine, but they can occasionally cause problems for children or the elderly. The most tricky complication is pneumonia, which is when your lungs get inflamed and can build up with fluid.