The Guardian (in 2017) chose to highlight this study
In 1984, researchers at the University of Wisconsin-Madison decided to investigate one of the best-known ways of catching a cold. They infected volunteers with a cold virus and instructed them to kiss healthy test subjects on the mouth for at least one minute. (The instruction for participants was to use whichever technique was “most natural”.) Sixteen healthy volunteers were kissed by people with colds. The result: just one confirmed infection.
That seems a bit odd, given that other studies of the time (e.g. a 1982 one) found more infections by handling an infested cup
A study by Gwaltney et al. (29) observed that 50% of subjects developed infections after handling a coffee cup contaminated with rhinovirus.
So have there been other studies on mouth-to-mouth kisses as the transmission route of the "common cold"? Or at least do we know more details about that 1984 study (e.g. the Guardian doesn't even say what virus was involved) to say why the transmission rate was so low in it?