Key word being "mostly" in that quote. If you want to hear his description regarding DNA vaccines, just read the next paragraph of the article - quoted below:
“The DNA [in DNA vaccines] does not integrate into the cell nucleus so this isn’t genetic modification - if the cells divide they will only include your natural DNA. But this approach is incredibly promising for COVID because it can be scaled up very quickly, and is very versatile - it is easy to synthetically produce DNA sequences that match the required bits of viral genetic code.”
We can’t rule out reverse transcription in the human body. It’s a very real possibility that introducing RNA results in longer lasting genetic change. Probably not! But I’d rather risk covid myself. So should all fertile people. At least until we know more.
“The DNA [in DNA vaccines] does not integrate into the cell nucleus so this isn’t genetic modification - if the cells divide they will only include your natural DNA. But this approach is incredibly promising for COVID because it can be scaled up very quickly, and is very versatile - it is easy to synthetically produce DNA sequences that match the required bits of viral genetic code.”