For the Orthodox Theophany is known as the Feast of the waters. Water is one of these special things that God has given us. Water when blessed retains the blessing. It retains the the action of God’s grace. So if we drink a little each day and we sprinkle in our homes, that blessing that has been given to the water is then given to our homes to us. God’s grace is active in our lives and we receive God’s grace when we use Blessed Holy Water this way.
I have chosen not to bless my monks, nor my spiritual children, to take the vaccine. I do not think any vaccine will prevent anyone from getting Covid, and I have read with increased horror as the evidence has become increasingly clear within the scientific community that this vaccine is in reality causing the spread of this virus within the human community, while preventing natural immunity.