Let me explain.
First of all, I worked banquets and cleaning rooms in hotels in college. We washed glasses with industrial cleaner before machine washing. The reason being was lipstick. A syphilis virus can live through two machine washings living in lipstick. I’m sure the flu virus is no different.
Second, I wash altar linens. They must be pretreated because of the amount of lipstick on them. An EMCH wipes the rim of a cup with a dry cloth. This spreads any germs around that rim.
So lets look at this scenario. Congregant A drinks from a communial cup and puts her lipstick smear on the rim. EMHC wipes the rim, sending lipstick around it. Congregant B walks up with the flu. His lips touch and leave the virus. The EMHC then wipes again, spreading the virus around the cup and into the lipstick while turning the cup. The virus is now at the top. Congregant C sips and the cup is wiped and turned. Congregant D now sips. The lipstick holding the virus is now on his bottom lip, to be licked. The wine will not kill what is encased in lipstick because there is no degreasing agent.
Along with that, Altar Wine has a 10% alcohol content and is not pure at that. It’s water AND wine. It takes 40% ethanol alcohol to kill a virus according to the CDC.
http://www.cdc.gov/ncidod/EID/vol12no03/05-0955.htm
Avoid the cup.
**An EMCH wipes the rim of a cup with a dry cloth. This spreads any germs around that rim.**
If the Extraordinary Minister puts the cloth, unfoled between their forefinger and middle finger, and pulls down a new place to wipe the rim of the cup, germs are not spread. I have even asked people to wait, while I turned the cloth over and started on the back side of it. I also inspect the inside of the cup and sometimes (Usually always) wipe it too, becuase some older people have some backwash. It’s a race sometimes to get to the backwash before it gets to the wine, though! LOL! My purificators are always all used up and usually as wine-stained as the priest’s!