I went to a funeral last night (not flu related - cancer) the girl was only 54.
There was talk (humorous) amongst the elders that we could no longer hongi, as is usual when the hosts (locals) meet and greet visitors - in this case, over 300 people.
Of course we've had no deaths here and only 4 confirmed cases of corona so far but the concensus of opinion was that such a deeply held spiritual belief surrounding the hongi, is far more important than getting flu (corona, bird, asian or just plain A, B or C).
Some newspapers have reported that Maori tribes have banned it.
Not true, it's a taupāruru, a caution - which gives people choice.
Do they think it is more important to show respect to a visitor by offering this spiritual greeting?
Or would it show more respect by just an impersonal shaking of hands, to minimise the risk of giving or getting infection?
We decided to hongi - and 300 people is a lot of folk to mingle breath with. 
Few Kiwis will know that shaking hands is really a proof that you are not going to draw your sword and attack
It has no spiritual meaning.