Dept of Bacteriology, UCL Medical School, London, UK. g.rook@ucl.ac.uk
Modern vaccinations, fear of germs and obsession with hygiene are depriving the immune system of the information input upon which it is dependent. This fails to maintain the correct cytokine balance and fine-tune T-cell regulation, and may lead to increased incidences of allergies and autoimmune diseases. If humans continue to deprive their immune systems of the input to which evolution has adapted it, it may be necessary to devise ways of replacing it artificially.