In virology, coinfection includes simultaneous infection of a single cell by two or more virus particles.
[citation needed] Global prevalence or incidence of coinfection among humans is unknown, but it is thought to be commonplace,[1] sometimes more common than single infection.
[5] The general patterns of ecological interactions between parasite species are unknown, even among common coinfections such as those between sexually transmitted infections.
[11] Coinfections sometimes can epitomize a zero sum game of bodily resources, and precise viral quantitation demonstrates children co-infected with rhinovirus and respiratory syncytial virus, metapneumovirus or parainfluenza virus have lower nasal viral loads than those with rhinovirus alone.
Coinfections appear to be common and several pathways have been identified for transmitting multiple virions to a single host cell.