Strong Evidence for the Safety of MMR and DPT Vaccines

In a large case-control study, researchers found no risk for encephalitis or encephalopathy from MMR or DPT vaccination.

Both the diphtheria-tetanus-pertussis (DTP) and the measles-mumps-rubella (MMR) vaccines have been suspected of increasing the risk for encephalopathy or encephalitis. Such suspicions led to decreased vaccination rates in some countries during the 1970s. Although many countries now use DTaP vaccines, in which the pertussis component is an acellular product rather than a killed whole-cell preparation, concern has continued because DTP is still widely used in developing areas. Previous studies either have produced indeterminate results or have failed to prove an association. Because these neurologic outcomes are rare, the studies lacked sufficient power to satisfy many experts who evaluated the data.

Now, in a retrospective case-control study …

Reviewing Author

Robert S. Baltimore, MD