Periodically, microorganisms (viruses, bacteria, etc) remind humans that they do not reign supremely on earth. This reminder is often devastating and humbling. For example, consider the recent invasion of the virus COVID-19. This virus (as are all viruses) is not considered to be a living organism, yet it is able to kill many humans across the globe in a very brief period. That is power, evil power. There have been other evil viruses in the past (the influenza H1N1 virus, HIV, SARS, Ebola, etc). However, the virus most comparable to COVID-19 is the 1918 H1N1 influenza virus. The onslaught of H1N1 on humans in 1918 (101 years ago) was also humbling and devastating when measured in terms of lives lost, social and economic loss. In fairness to viruses, they do not set out to wage war against humans. They seek humans as hosts in order to survive. However, their presence in humans as uninvited guests is dangerous. Consequently, they have become enemies of humans and so they must be eradicated. Unfortunately, humans have not been able to eradicate some of the most dangerous viruses. In fact various strains of the H1N1 virus continue to kill many humans one hundred years after it was first identified. There are two primary reasons viruses continue to kill humans in large numbers: viruses are extremely difficult to eradicate; and humans are very stubborn (particularly humans in free societies).
The virus is not a living organism because it does not meet all the prerequisites for the classification. It is essentially a chemical agent made up of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA. These group of viruses are called retroviruses). The DNA is protected by a protein coat called the capsid. Some viruses have a lipid membrane (envelope) that covers the capsid and many viruses called naked viruses do not have an envelope.
The virus is a micro-micro substance when compared to some other micro substances. For example, the virus is about 10,000 times smaller than the diameter of a human hair; 10 times smaller than a bacterium cell and 100 times smaller than a human cell. Consequently, the virus is invisible to the unaided human eye.
The virus survives by entering a host cell (in this case the human cell). The virus' favorable entry point is in a cell with ample distribution of the virus' receptor molecules. For example, COVID-19 prefers the mucus lining cells of the lungs and airways. On successful entry, the virus begins several actions (called the lytic cycle) that take over the operation of the cell and eventually kill the cell:
(1) Adsorption: virus attaches to the host cell
(2) Entry: virus injects its DNA or RNA into host cell. Injected DNA or RNA enlists host cell enzymes to work on its behalf in a take over operation.
(3) Replication: recruited cell enzymes begin to replicate new virus particles.
(4) Assembly: replicated virus particles assemble to form more viruses.
(5) Release: new viruses kill the cell in order to break away to seek new host cell.
Antigenic drift is a sustained and rapid viral evolution powered by mutations in the genes that encode the antigen proteins of some viruses. Antigenic drift produces new strains of a virus. As a result, the virus becomes very difficult to eradicate. For example, the Influenza A H1N1 virus is characterized by antigenic drift (a primary reason why many continue to die directly or indirectly from the Influenza virus).
Human responses to viral attacks are often reactive: a virus attacks, its DNA or RNA sequence is studied, testing and a vaccine are produced. Additionally, other mitigative (handwashing, social grouping restrictions, etc) and therapeutic responses are also implemented. These are important and effective responses. In fact, only reactive responses are immediately possible with respect to viral attacks from new viruses. However, reactive responses must be refined to be expectational. In other words, a virus alert and mitigation infrastructure must be in place permanently as preparation for the worst case scenario of viral attacks. Fortunately, the COVID-19 experience and guidelines can be templates for establishing a permanent and effecient virus alert and mitigation infrastructure. Switching Containership (thats what social distancing is) is the core of such infrastructure. In other words, space occupancies at normal times are switched to mandated space occupancies during virus alerts. For example, an employee's office work space is switched to a home work space (i.e the employee works from home); and a student's school learning environment is switched to a home learning environment (i.e. the student learns from home). These switches have been implemented in many spaces across the globe as the world goes through the COVID-19 onslaught. The infrastructure that incorporates them into global and national virus alert systems need to be established efficiently and permanently in order to minimize future damages caused by viral attacks.
Why was an efficient virus alert and mitigation infrastructure not in place even though its been over a century since the onslaught of the H1N1 virus of 1918? Some say that it is in place. Perhaps. However, what was in place prior to COVID-19 was not prepared to take on COVID-19. A common expression of human stubborness is defiance (there are good defiances and bad defiances). Some defiances will definitely emerge in free societies as champions of freedom (i.e. freedom to defy virus alert mandates of an efficient virus alert and mitigation infrastructure). However, most people will understand that sometimes selective freedom is necessary in free societies.