Selective effects of colds and influenza on human performance efficiency: a critical appraisal.

This paper provides an appraisal of the results published from the MRC Common Cold Unit on human performance efficiency during minor upper respiratory tract infection, i.e., colds and influenza. Despite strict controls employed in the methods of data collection, the robustness of the results and some of the conclusions drawn are questioned. In particular, the claim that colds and influenza lead to selective (and different) effects is criticised as being based on incomplete data. The lack of replication, the small sample sizes, possible response biases and use of controls are considered. Overall, it is argued that there are insufficient data to provide conclusive evidence for selective effects and that over-generalisation from such studies can be misleading.