If you're going to worry about foreign DNA, here's something to think about: Every inch of your skin is crawling with thousands of bacteria and fungi that each carry the DNA of their species. Like many people, you may be colonized with varieties of staph bacteria that can cause disease. The interior of your mouth and throat is crawling with millions of microorganisms that all carry packages of DNA. Have you ever gotten a cavity that needed to be filled by a dentist. If so, then you probably have a species of strep living in your mouth that caused the decay. Your own genitalia are covered with bacteria and fungi. Even a virgin girl's mouth and vagina are densely populated with bacteria cells and fungi spores, all full of DNA. If you shake hands with another man, you pick up microbes from his hand that might include the COVID virus. Every time you inhale, you breath in bacteria and mold spores.

The only way you could get rid of all this foreign DNA would be to douse yourself with gasoline and light yourself on fire. That would be foolish because we all actually need to be covered in bacteria. Most of it is harmless and actually prevents really nasty bacteria from gaining a foothold by crowding it out. (Though some nasties will still survive on any of us.)

Save your anxiety about DNA for genetic material that can actually sicken or kill you.