How serious are these attacks?
At this time the attacks are not considered serious since the exploits are not using a wormable (automatic) means of spreading.
While this is true, Beaumont and Microsoft have cautioned that more stable exploits are likely to follow. Beaumont points to a blog post that discusses why the current exploits are mostly causing crashes upon systems and how to make the exploit more stable. Beaumont has stated over 724k system remain exposed to this vulnerability.
How can I protect my organisation or myself from this vulnerability?
For workstation systems, as recommended in my previous post, please install the Microsoft update if your system is vulnerable. Beaumont and Microsoft provide recommendations specific to organisations in their respective posts to both mitigate the vulnerability and to locate vulnerable systems within your network.