You must have Flash player installed. Click here to install.

MARK SAWYER, MD: We give a lot of vaccines now to young babies and, for me, that's a great thing because we're protecting them against diseases. We give vaccines as early as we can because young babies are the most susceptible to severe consequences from the infections that we can now prevent.

MARY BETH KOSLAP-PETRACO, DNP(c), CPNP: We do very rigorous testing to make sure that when we're giving the vaccines, it's the right vaccine, at the right age, at the right time.

PAUL A. OFFIT, MD: I mean, whooping cough traditionally killed young infants, as does rotavirus, as does pneumococcus, as does Haemophilus Influenzae Type b (Hib). So you need to try and get children to a position where they're as immune as they can be at the time when they're most likely to face these diseases.

MARK SAWYER, MD: In addition to that, for some vaccines we need two or even three doses before babies are protected. So we want to start as early as possible so we can protect them as soon as possible.