Drug company Pfizer says its Prevnar 13 vaccine against pneumonia, blood and other infections has performed well in a huge study of older patients.  The research included about 85 people aged 65 or older.

Scientists found that compared to study participants getting a placebo shot, those getting the vaccine had about 46 percent fewer cases of pneumonia and about 75 percent fewer cases of invasive pneumococcal disease such as bloodstream infections.  Prevnar 13 is the top selling vaccine in history and brings Pfizer about four billion dollars in annual revenue.