Before the chicken pox vaccine was available, about 100 Americans died each year from serious complications of chicken pox. Even so today, you still hear some parents say, 'Well, my son got the shot and then he got chicken pox anyway.' That's why the Centers for Disease Control has been studying cases like that for the last five years and here's what they found.
"It was 100% effective in preventing severe disease, 92% to 100% effective in preventing moderate or severe disease and 80% effective in preventing all forms of chicken pox," says Dr. Jane Seward, of the Centers for Disease Control.
In other words, kids who were protected by the vaccine and then later got chicken pox anyway suffered mostly mild cases, with shorter illness, fewer itchy bumps and were much less contagious to children who had not been vaccinated yet. That's a big deal because babies can't get that vaccine until their first birthday so they need to be around other people who've been immunized.