As far as I understand it so far, it is ultimately just flu. I would be inclined to say, business as usual. You would need business continuity procedures (you all should have them in the event of fire or any disaster) to be up-to-date incase larger numbers of staff were hit but other than that, there isn't much that can be done. If staff are showing flu symptoms then it may be wise to encourage people to work from home but the problem with cold and flus is that normally by the time you realise it's definitely flu and not a bad(ish) cold, you've already passed the virus on.
The government is no longer trying to contain the virus either.
It's important to ensure that staff are reassured - it would be wise not to panic them