Abhi Yes, it'll work fine, but it will be susceptible to exploit from unpatched vulnerabilities that may reside in the system itself. This is what generates such a high risk. Also, don't confuse "antivirus" with "anti malware". In most cases, these are two different products targeting different areas.
These days, viruses still exist, but are "all but dead" in the sense that Malware and Ransomware can do so much more in terms of damage and exploitation in order to make you pay to release access to critical data. Even with the latest and greatest Malware Endpoint software, this will stop the exploit, but not patch the vulnerability that exposed it in the first place.
Security through obscurity is a dangerous misconception.