The Non-Life of a Virus
It is questionable whether a virus is alive because it must parasitize a host cell to reproduce.
Barring any social or mystic philosophies, the point of life, according to basic biological processes, is to reproduce. Passing on one’s DNA is, in a sense, living forever, and all living creatures can do this either asexually or sexually.
Every living organism has a related virus that can infect it. Even bacteria and fungi can be infected with viruses. Viruses are more numerous than every other creature that is considered to be living.
Are Viruses Alive or Dead?
What even defines living? Viruses are fascinating because biologists cannot agree whether they are living creatures. The main reason why the concept of viruses being alive is questionable is that viruses cannot reproduce on their own, sexually or asexually. They require a host to reproduce.
Unlike organisms that fit the general model of life proposed by biologists, the virus can indefinitely remain dormant until it comes into contact with an appropriate host. When this occurs, the virus activates and begins replication or reproduction. More appropriately, the virus tells the cell to do the replicating for the virus.
In the Scientific American article “Are Viruses Alive,” Luis P. Villarreal says, “Most known viruses are persistent and innocuous, not pathogenic. They take up residence in cells, where they may remain dormant for long periods or take advantage of the cells’ replication apparatus to reproduce at a slow and steady rate.”
How Viruses Replicate
Nucleic acids are the road maps that cells use to reproduce in a certain manner. Living organisms consist of DNA and RNA, two types of nucleic acids that have different roles. Viruses consist of either DNA or RNA enclosed in a protein capsule.
When a virus finds a host, which is a cell, it releases its protein coating and uses the reproductive processes of the cell to replicate the viral DNA or RNA. The host cell is also used to create protein coatings for the new viruses. The newly-created viruses leave the cell in clusters or the cell membrane ruptures releasing all of the viruses at once.
The concept of using a “dead” virus for flu shots can be considered to be a moot point. The virus is not “dead,” but inactivated. According to Henry Bernstein, D.O., a Harvard Medical School Senior Lecturer and Dartmouth Medical School Professor, “Killed or inactivated is the same thing when we talk about vaccines. A vaccine usually is made up of the infectious germ itself, either killed (inactivated) or ‘live-attenuated’ (weakened)…which builds a much stronger immune response against the virus than the killed (or inactivated) types do.”
While viruses may be referred to as inert biochemicals or molecules that are components of living systems with little chemical reactivity, they serve as an evolutionary model that can be studied within a short period of time. This is unusual because most evolutionary models take decades or centuries to complete. While the rapid evolution of viruses is the bane of vaccine developers, the behavior of these lifeless parasites is, oddly enough, useful for learning about life.