It has been reported from lots of sources that an upgrade of the free version of the Avast! antivirus is recognizing many websites as infected by a Virus.
These websites are not infected, it is the Avast! software which is reporting erroneously false positive infections.
If you are concerned by this false positive, the solution is to disable temporarily your antivirus because Avast! Free does not permit to authorize websites individually:
The problem will be solved within the next 24 hours by the Avast! engineers.
Thank you for sharing the information with your co-workers.