"Bishops defying swine flu advice" said the headlines recently.
Some bishops in England have recently reinstated using a shared chalice to distribute communion wine. UK Dept of Health advice is to suspend this practice during the swine flu outbreak to prevent the spread of this disease. I can see why chalices were identified as potentially spreading infections but church goers should take heart because drinking wine from a shared silver communal vessel may be safer than sharing a cup of water.
Wine kills disease-causing bacteria and viruses. Wine or beer was drunk in the past in preference to water when water supplies were suspect. Our ancestors knew from trial and error that these drinks were safer. Its not just the alcohol that can kill bacteria and viruses, phenolic compounds in wine such as resveratrol do so as well. There is a lot of research examining this topic at the moment. I found one very speculative paper listed on Global Health database that suggests resveratrol could be used as part of a treatment for flu in the absence of other treatments.
The chalices themselves may also play a part. They are often made of silver and this also kills bacteria. Silver coated instruments are widely used in hospitals to prevent infections and silver impregnated fabrics are being investigated as well for use in dressings and in disinfectants.
I don't know if the combined effects of the wine and the silver are enough to prevent diseases spreading from communion chalices but they could reduce it. There is evidence that some bacteria do survive on chalices used in Church. I found a study listed on Global Health that examined 15 chalices and found slightly more than a quarter of them had contamination with disease causing bacteria. Nevertheless the study concluded that chalices are reasonably safe if you are healthy.
Infection from the communion cup: an underestimated risk? Fiedler, K.; Lindner, M.; Edel, B.; Wallbrecht, F.; Zentralblatt für Hygiene und Umweltmedizin, 1998, 201, 2, pp 167-188,
Inhibitory activity of diluted wine on bacterial growth: the secret of water purification in antiquity. Dolara, P.; Arrigucci, S.; Cassetta, M. I.; Fallani, S.; Novelli, A. International Journal of Antimicrobial Agents 2005 pp. 338-340
Antimicrobial effects of wine on Escherichia coli O157:H7 and Salmonella typhimurium in a model stomach system. Just, J. R.; Daeschel, M. A. Journal of Food Science 2003 Vol. 68 No. 1 pp. 285-290
A nutritional supplement formula for influenza A (H5N1) infection in humans. Medical Hypotheses 2006 Vol. 67 No. 3 pp. 578-587