Some bacteriophages inject their genomes into bacterial cells (to not scale) Viral populations tend not to increase by way of cell division, because they are acellular. Shingles only happens in those who’ve experienced chickenpox eventually. It’s a reactivation on the varicella-zoster virus that’s been lying dormant with your cells. https://www.youtube.com/watch?v=6xfiggqKKjA