Viruses are much smaller than bacteria, have many different shapes, and contain a nucleic acid core (DNA or RNA) surrounded by a capsid, or protein coating.

1. A virus lives and multiplies itself in a host cell.
2. First it invades a host cell, multiplies and replicates itself, and then enters the body by destroying the host cell.
3. Types of viral diseases include: SARS-CoV-2 (Covid-19), Hepatitis A, B, and C, HIV, Herpes, Measles, the common cold, influenza, and mononucleosis.
4. Viruses can mutate.
5. There are some vaccines to help prevent the contraction of certain viruses such as Hepatis B and SARS-CoV-2.