When I was younger, the mark of the beast was supposed to be a computer chip implanted in your right hand or forehead. Now it's a vaccine which is administered into the shoulder intramuscularly. Right or left!
I'm in the first wave of people to receive the vaccine and I plan to get it once it's available to me. I don't believe that the vaccine is the mark of the beast nor that the mark was intended to be understood with such physical literalism. Consider the following:
Mark/Name/Seal of God
The one who conquers, I will make him a pillar in the temple of my God. Never shall he go out of it, and I will write on him the name of my God, and the name of the city of my God, the new Jerusalem, which comes down from my God out of heaven, and my own new name. - Revelation 3:12 (ESV)
“Do not harm the earth or the sea or the trees, until we have sealed the servants of our God on their foreheads.” - Revelation 7:3 (ESV)
Then I looked, and behold, on Mount Zion stood the Lamb, and with him 144,000 who had his name and his Father’s name written on their foreheads. - Revelation 14:1 (ESV)
No longer will there be anything accursed, but the throne of God and of the Lamb will be in it, and his servants will worship him. They will see his face, and his name will be on their foreheads. - Revelation 22:3-4 (ESV)
Mark/Name of the Beast
And it was allowed to give breath to the image of the beast, so that the image of the beast might even speak and might cause those who would not worship the image of the beast to be slain. Also it causes all, both small and great, both rich and poor, both free and slave, to be marked on the right hand or the forehead, so that no one can buy or sell unless he has the mark, that is, the name of the beast or the number of its name. - Revelation 13:15-17 (ESV)
And another angel, a third, followed them, saying with a loud voice, “If anyone worships the beast and its image and receives a mark on his forehead or on his hand, he also will drink the wine of God’s wrath, poured full strength into the cup of his anger, and he will be tormented with fire and sulfur in the presence of the holy angels and in the presence of the Lamb. - Revelation 14:9-10 (ESV)
And the beast was captured, and with it the false prophet who in its presence had done the signs by which he deceived those who had received the mark of the beast and those who worshiped its image. - Revelation 19:20
Then I saw thrones, and seated on them were those to whom the authority to judge was committed. Also I saw the souls of those who had been beheaded for the testimony of Jesus and for the word of God, and those who had not worshiped the beast or its image and had not received its mark on their foreheads or their hands. They came to life and reigned with Christ for a thousand years. - Revelation 20:4 (ESV)
Briefly, I think a more consistent interpretation is to understand the respective marks as representing spiritual allegiance, whether to Christ or Satan. Interpreting the mark as a physical sign resists the symbolism of the Revelation and creates a mess of confusion and panic when the book was meant to be a source of great encouragement for Christians throughout the interadvental period. Our hope is in Christ and his victory which we see on glorious display all throughout the Revelation!