Viruses can only replicate themselves by infecting a host cell and therefore cannot reproduce on their own. ... They are similar to obligate intracellular parasites as they lack the means for self-reproduction outside a host cell, but unlike parasites, viruses are generally not considered to be true living organisms.
Viruses rely on the cells of other organisms to survive and reproduce, because they can’t capture or store energy themselves. In other words they cannot function outside a host organism, which is why they are often regarded as non-living
