Sexual transmission has been described as the primary route of spread during the 2022 mpox (formerly known as monkeypox) outbreak. In a case series of mpox infections in cis women and non-binary individuals, non-sexual routes or unknown routes were implicated in 39% of cases.  This case series is consistent with our experience treating cases of mpox without sexual exposures, in which the route of transmission remains unclear. Understanding non-sexual transmission of mpox is important for at least three reasons.

First, there is a plausible risk that circulating strains could gain transmission-enhancing mutations. Immunocompromised patients have had prolonged infections that increase the chance for mutations to arise during ongoing replication. Moreover, cryptic transmission can lead to further mutation over time in all hosts. A more transmissible strain could allow for currently less effective routes of transmission to propagate. For instance, during the current outbreak, researchers from Spain recovered high loads of mpox virus DNA, as well as culturable virus, from patient saliva samples.