A virus is a tiny, infectious agent that can only replicate inside the living cells of other organisms. It is not a living cell and has no metabolism of its own. Examples of viral infections include the common cold, flu, HIV, and COVID-19.
Bacteria are single-celled microorganisms that are found almost everywhere. Most bacteria are harmless, and some are even beneficial to humans. They are living organisms with their own metabolism and can reproduce on their own. Examples of bacterial infections include strep throat, urinary tract infections, and some types of food poisoning.
So, the main difference between viruses and bacteria is that viruses are not alive and need a host cell to reproduce, while bacteria are living organisms that can reproduce on their own.