It's certainly shows creativity ! Thinking this through, as I write,
And there is certainly a grain of truth in it i.e. an experienced contractor would have not judged at the Contract Date that "surfaces MIGHT BE infected with Coronavirus" had such a small chance of occurring that it would have been unreasonable to have allowed for them.
And I think the MIGHT BE is the key here: we do not know if they are, so the Contractor has not definitely encountered them. But on civil law, it is on the balance of probability. Not that I am in any way an expert on COFID-19, but I think it is unlikely that the virus would be on any individual surface at the moment, especially if people - and the Contractor - are taking precautions.
So for the time being no, but if it becomes a total endemic, then it might become one, BUT if it reaches that stage, society would probably be in a total lockdown.