From 1979

The coronaviruses are transmitted by the respiratory route. It has been possible artificially to induce infection in human volunteers by inoculating virus into the nose (7, 59). No other route of transmission for coronaviruses seems involved in man, although animal

coronaviruses are infectious by the fecal-oral route (56). There is no direct evidence to aid in identifying the main mechanisms of transmission. However, it is possible to compare the epidemiologic behavior of the coronaviruses with other respiratory agents whose transmission

mechanisms have been more directly studied. Large scale outbreaks of coronavirus infections have taken place, as in Tecumseh in 1967 (16). This is much more analogous to the situation seen with influenza than it is with the rhinoviruses. It is likely that the former agent can be

transmitted by aerosol in addition to large droplet, which would explain its ability to spread quickly (19). Rhinoviruses on the other hand are transmitted by large droplet and at times may spread via fomites (27), but not by aerosol. It is therefore probable that human

coronaviruses can be spread by aerosol as well as by large droplet. Aerosol transmission has actually been documented in poultry by the agent of avian infectious bronchitis (20).

My mistake 1974.