Objectives: The incidence of many serious infectious diseases fundamentally decline as a success of consequent vaccination regimens. However, it is a matter of discussion if vaccination might cause unspecific negative side effects on the immune system. To answer this, we performed a clinical study on children with the question as to whether there is an enhanced frequency of infection diseases after vaccination or not.
Methods: The study population (n=496) was randomized to a group of vaccinated children (first vaccination on the 60th day of life, n=201) and a group of unvaccinated children (first vaccination on the 90th day of life, n=295). Frequencies of unspecific, morbidity-related signs were recorded by the mothers with a diary card. These data were taken for further statistical analysis to determine if the factor "vaccination" does have a significant effect on the variable "morbidity".
Results: Various infectious disease-associated symptoms (vomiting, coughing, signs of rhinitis, restlessness, rash and pain) were significantly less often seen in vaccinated than in non-vaccinated children.
Conclusions: Our study revealed that children who received vaccination against diphtheria, pertussis, tetanus, HiB and poliomyelitis simultaneously within the third month of life do not exhibit enhanced frequencies of infectious disease-associated symptoms. In contrary, the frequencies of infection-associated symptoms were found to be significantly reduced. This might be caused by a vaccination-associated unspecific enhancement of immunological activity (e.g. mediated by interleukin 2) or by other presently still unknown factors.
Copyright 2000 The British Infection Society.