Increasing number of childhood vaccines does not increase risk of other diseases

In an extremely large study of 805,206 children (all the children born in Denmark from 1990 to 2001), there was no greater risk of serious or mild infections as the number of vaccines given to children increased. It has been hypothesized that increasing the number of vaccines received by children might “overload” the immune system and increase the risk of other diseases. There has never been any evidence of this fact, but it has been felt to be a biologic possibility. There have been smaller studies in the past looking at this issue and no risk has ever been found. This is likely the largest and best-designed study to look at this issue. They found no greater risk of any infection, from common colds and diarrhea to pneumonia and meningitis as the number of vaccines increased. The study was not funded by vaccine manufacturers. Despite concerns about vaccine safety, solid research continues to show them to be highly safe and effective.