Viruses spread by infecting cells and replicating within them. There are several ways that viruses can spread from one person to another:
Direct contact: Viruses can be spread through direct contact with an infected person, such as through shaking hands or hugging.
Indirect contact: Viruses can also be spread through indirect contact, such as by touching a surface or object that has been contaminated with the virus and then touching one's face, mouth, or eyes.
Respiratory droplets: Some viruses, such as the virus that causes COVID-19, are spread through respiratory droplets that are produced when an infected person talks, coughs, or sneezes. These droplets can land in the mouths or noses of people who are nearby or be inhaled into the lungs.
Sexual contact: Some viruses, such as HIV and herpes, are spread through sexual contact.
Overall, viruses can spread through a variety of means, and the specific method of transmission can depend on the specific virus and the mode of infection.