... should I be worried?

Only if you like being worried!

In 27 years I have only ever come across 8 viruses... and MacKeeper.

I have found none at all in the last 14 years... on any of the thousands of Macs I have owned or looked after.

The only ones I’ve found were on OS 6 to 9 and none of those were more than an inconvenience.

Of course, there are people with vested interests in telling you that Macs aren’t immune, and even go on to list a whole load of things that you need to do to make your Mac secure - but, oddly enough, they NEVER give any information about the threats that they CLAIM exist for Macs!

Take https://www.getsafeonline.org/protecting-your-computer/safe-mac-use/ as an example:

Apple Macs are less vulnerable to attack by malware than PCs. Many people, in fact, believe that Macs are immune to viruses and spyware, but this is definitely not the case.

Unfortunately the rest of the page only serves to demonstrate the LACK OF THREAT TO MACS!

I can only surmise that the people who inhabit the Windoze world are victims of the “Wishful Thinking Virus” and that they only FEEL safe if they can convince themselves that Macs are also vulnerable.

I find it all a bit sad really as it undermines their greatest claim about Macs: they are expensive.

When you add up the money that Windoze users spend updating to the latest version of Windoze, and then instantly regret it and downgrade back to the last version that worked acceptably well, and then add in the cost of all that super-duper online/virus/malware protection and the massive performance hit that goes with it every time you try and do anything... oh, and the fact that the average Mac lasts around 5 to 6 years - all Macs from 2008 on will run Yosemite when it comes out - the real cost of owning a Mac is way less than owning and running a PeeCee.

So, if you WANT to be worried then you can throw money at some AV software if you wish, but when you look at the database of known Mac threats you won’t find a single VIABLE threat to your Mac. The last known threat to the operating system was cancelled out in Snow Leopard. The ONLY “vulnerabilities” found at pwn2Own (annual hacking competition with big money prizes) have been in Safari... which Apple regularly updates and closes down loopholes. Would AV software do a better job? No. They rely on the likes of Microsoft not giving a monkey’s about security, preferring instead to leave it to 3rd parties to take money from you.

The ONLY thing you should have on your Mac is Malwarebytes you don’t need to pay for the premium version after 14 days, just run it if you think you’ve picked something up.