Boris Johnson gave the go-ahead for Christmas parties and nativity plays, but a government minister warned against festive kissing.
Speaking on Peston, the work and pensions secretary, Thérse Coffey, said that they should all be trying to enjoy the Christmas ahead of them, but that they don't think there should be much snogging.
Experts agree that this would be a risky business.
Catherine Noakes, professor of environmental engineering for buildings at the University of Leeds, said that kissing is likely to pose a risk.
She said that sharing the same air and interacting together in a poorly ventilated room with multiple people is probably a higher risk.
Taking steps to reduce the number of people in a space and ensure that it is well ventilated are likely to be of greater benefit.
The director of the Centre for Behaviour Change at the University College London and a member of the behavioural science advisory group Spi-B warned that small aerosol particles can hang in the air for many hours.
She said that the biggest danger at Christmas parties is people talking loudly, singing and laughing.
A Christmas schmooze is not the only risk that should be considered, according to Dr Simon Clarke, an associate professor of cellular microbiology at the University of Reading. Heavy breathing makes dancing problematic.
It is a good idea to keep personal space and good hand and face hygiene. The virus is easy to transmit from person to person in a close proximity situation. People shouldn't expect masks to be an "invincible barrier" if they are properly fitted and cleaned.
He said that this was not a matter of being fun police. You can catch Covid at a funeral wake just as easily as you catch him at a party.
