CAN YOU CATCH A COLD FROM THE COMMUNION CUP?
The chalice or cup used at Mass is just as likely (or just as unlikely) to transmit disease as is any other cup that is shared among multiple people. The Consecration has no effect whatsoever on this.
Why? Because the Consecration affects only the substance of the wine, not its accidents. After the Consecration, what is in the cup is properly called the Blood of Christ, but it maintains all the outward properties of wine. Moreover, the Consecration has no effect on anything in the cup that is not wine.
If there are any contaminants in the wine prior to the Consecration, they remain in the cup. The contaminants are not themselves transubstantiated into the Blood of Christ. So, if there had been a particle of dust prior to the Consecration, there remains a particle of (unconsecrated) dust afterward.
Similarly, any foreign substance, such as a bacterium or virus, that is intruded into the cup after the Consecration remains what it is. It does not become consecrated into the Blood of Christ–nor does it lose its nature as a bacterium or virus.
Some pious people think that any contaminant, of any sort, is somehow neutralized by the Precious Blood. This is not true.
Others think that bacteria and viruses in particular are neutralized by the alcoholic nature of the now-consecrated wine. Again, untrue.
Alcohol kills only in almost-pure concentration. Altar wine commonly is no more than about 12 percent alcohol, far too low a percentage to kill off microscopic intruders. So, even though the consecrated wine (now the Precious Blood) maintains the accidents of the wine and, thus, the alcoholic properties that the wine had, those alcoholic properties aren’t enough to get rid of bacteria or viruses.
Bottom line: You are just as likely (or unlikely) to pass along disease through sharing a Communion cup as you are in sharing a cup of plain wine.
If you do not hesitate to use a wine glass that fifty other people already have used, then you should not hesitate to receive from the Communion cup that fifty other people already have received from.
If you think there is a problem with drinking from that glass of plain wine, you should think there is the same problem drinking from the Communion cup.
It’s your choice.