The flu can definitely set you up for bacterial pneumonias.

I've never seen this level of anger at parents who've chosen not to vaccinate their children.

When you're in the womb, you're in a sterile environment. When you enter the birth canal and the world, you're not. Very quickly, you have, living on the surface of your body, trillions of bacteria, literally trillion.

Today, however, anti-vaccine activists go out of their way to claim that they are not anti-vaccine; they’re pro-vaccine. They just want vaccines to be safer. This is a much softer, less radical, more tolerable message, allowing them greater access to the media. However, because anti-vaccine activists today define safe as free from side effects such as autism, learning disabilities, attention deficit disorder, multiple sclerosis, diabetes, strokes, heart attacks, and blood clots—conditions that aren’t caused by vaccines—safer vaccines, using their definition, can never be made.

What really reinvigorated vaccines was Prevnar, the pneumococcal vaccine that prevents against meningitis and ear infections. Here was the first vaccine to cross the billion-dollar mark.

Physicians who care for adults generally don't think about vaccines as much as pediatricians do, and adults think of vaccines as a kid thing.

One bacterium has 2,000 to 6,000 proteins.