I had my doubts about TeamViewer but when Jason Snell ( writes for Macworld) said it was ok, I thought I would post it here for a second opinion.
I do have ClamXAV which runs in the background and has on several occasions alerted me immediately when malware/virus is detected.
Thanks for your advice Joe.
OS 10.12.6 iMac (Retina 5K, 27", 2017, 3.4 GHz Intel Core i5, 24 GB RAM, 2400 MHz DDR4. Sierra. 10.12.6 SuperDuper. 1 TB Lacie HD, Noise Ninja.