Influenza vaccination and the activities of plasma acetylcholinesterase and butyrylcholinesterase in institutionalised elderly patients.

Influenza immunisation was given to 30 elderly institutionalised patients (mean age 80 years) and 16 young volunteers (mean age 27 years). Blood was taken at days 0, 2, 7 and 28. Plasma butyrylcholinesterase (BuChE) and acetylcholinesterase (ACHE) activities were measured. The activities of both enzymes were lower in the elderly patients compared to the young volunteers (P<0.001); however, influenza vaccination had no effect on either enzyme, in either age group.