The question of whether or not viruses are alive is an interesting debate. It is an interesting topic because viruses do have some of the basic characteristics of all living things.
For example, viruses contain DNA (or RNA). That is one of the foundational characteristics of life. All living things contain genetic material, so it makes sense that people might think that viruses are alive. Another characteristic of living things is that they are able to reproduce. Whether we are talking about the lytic or lysogenic viral life cycles, new viruses are created. It appears that viruses are capable of reproducing. The difference is that viruses are not capable of reproducing on their own. Viruses have to hijack a cell and use the cell's machinery to produce more viruses. A final reason that people tend to think that viruses are alive is because media outlets often talk about "killing" a virus through medications or vaccines. It sends the message that since a virus can be killed, it must be alive.
Probably the most important argument for viruses being nonliving is that they are not made of cells. Being made of at least one cell is a characteristic of living things. Viruses are not made of cells; therefore, they are not living. The three parts to modern-day cell theory also support the fact that viruses are not living. Cell theory states that cells are the fundamental unit of life and living things. Again, viruses do not contain cells, so they should not be considered living.