The CDC has found no documented transmission of any infectious disease has ever been traced to the use of a common communion cup. The consensus of the CDC is that a theoretic risk of transmitting infectious diseases by using a common communion cup exists, but that the risk is so small that it is undetectable—you are far more likely to catch something by shaking someone’s hand than by drinking from the common cup.
Is there any health risk in drinking from the Common Cup at Holy Communion?
The CDC has found no documented transmission of any infectious disease has ever been traced to the use of a common communion cup.