In general, viruses can’t infect through intact skin. It’s generally believed that infection through skin requires some amount of skin damage, even in the case of herpes simplex I (HSV1, the “cold sore virus”) which is highly adapted to humans and spreads pretty effectively.

On the other hand, it’s probably relatively common to have some amount of skin damage just from normal day-to-day living, so this doesn’t present a complete block to infections.

The details of how HSV gets through skin are still surprisingly unclear, including the amount of damage needed to penetrate.

> The general assumption is that skin lesions can serve as entry portals for HSV-1. Under in vivo conditions, damaged skin can result from various sources ranging from mechanical abrasions or burns to impaired epidermal barriers and dysfunctional immune responses causing eczema herpeticum … Taken together, we hypothesize that successful viral invasion via skin lesions in vivo requires more than mechanically disrupted intercellular junctions.

—Ex Vivo Infection of Human Skin with Herpes Simplex Virus 1 Reveals Mechanical Wounds as Insufficient Entry Portals via the Skin Surface