We know how viruses and germs spread. The theory and science is tested and verified.
Actually you are making an assertion by claiming that for a special reason germ theory suddenly stops working when it comes to communion. It is a logical fallacy.
Special Pleading
As you have admitted yourself there has been no test results submitted on any peer reviewed studies that would in any way or form confirm this.
And of course there will not be because the world does not work that way.
It is naive to think that if it could be demonstrated that Eucharist miraculously did something that the fact would not be politicized by ambitious politicos like Putin if not by the Church itself.
The current practices of Eucharist during this time will get people killed statistically whatever you personally know anyone affected or not.