Of the identifiable viruses, the most common skin cell-invading variety was the human papilloma virus, which can cause warts and is linked to some cancers. But the vast majority of identifiable viruses were phages—viruses that infect only bacteria.Some phages can kill off specific types of bacteria, thus altering whole bacterial communities that inhabit the skin. The viruses can also embed themselves in bacterial genomes and share genes, including those for thwarting antibiotics. These activities could help maintain a healthy microbial population or give disease-causing bacteria a hand.
Source: Vast, uncharted viral world discovered on human skin | Ars Technica