Anti-virus software makers are detecting malware that attempts to exploit the security vulnerabilities identified as Spectre and Meltdown. Since code must execute on the computer to exploit these vulnerabilities, anti-virus software is being updated to detect such malware attacks. Of course, some such malware may yet get through our defenses and could end up on machines.

Source: Meltdown-Spectre: Malware is already being tested by attackers | ZDNet

My view is that for most of us, its just another form of malware. We all need to be pro-active about avoiding malware by taking appropriate steps such as installing code we know to be good, using anti-virus software, and keeping our systems generally update. Meltdown and Spectre are just two more exploits that hackers can use.