Today I have been bombarded with questions about a New York Times opinion piece concerning coronavirus infections. This piece, written by a chemistry and genomics professor and grad student at Princeton, states that, “As with any other poison, viruses are usually deadlier in larger amounts.” The piece makes a number of statements about exposure to different amounts of virus, but the central hypotheses is “people are dying from coronavirus because they received a much higher amount of the virus.”
There is no data provided in the article supporting this hypothesis and none elsewhere. In fact, this concept is wrong in so many ways one wonders if anyone reviewed the article that understands virology!
Poisons are small molecule chemicals or proteins that interfere with specific activities in the body. The ability of the poison to harm someone is directly related to the amount of the chemical a person receives. Some poisons can be reversed by “antidotes.” These are chemical inhibitors of the poison or other things that neutralize the effect.
Good examples of poisons are pesticides, which block the ability of nerves to control muscles; and cyanide, which starves the body of energy by inhibiting mitochondrial enzyme systems. This also includes military weapons like nerve gas, which is very much like a pesticide, blocking neural activity and paralyzing an individual within seconds.
A virus is very different. It is an organism which is a molecular parasite that has its own genetic material and can reproduce. Once a virus gets into a host, like a human, it starts to replicate and uses the host cells to make copies of itself. As long as even a single virus particle gets into the proper host cell where it can replicate, it can cause infection, making as many copies of the virus as it needs. The host is killed not by a chemical inhibition of a cell but by destruction of its cells by the virus.
The only thing that saves a host from a virus is the immune response that kills and destroys host cells making the virus. The amount of virus that can kill someone depends on the ability of their immune system to defend against the virus. That is one reason we think the elderly are more susceptible to illness and death from COVID-19 infection.
Proving this, the threshold for a lethal virus dose – the amount of virus necessary to kill the animal- can be lowered by orders of magnitude in animals with stronger immune responses. In essence: same virus, differing immune response.
Many consider viruses as the simplest form of “life.” This is reviewed in an outstanding story in Scientific American. Viruses are able to change hosts of all types. They can change colors of flowers in plants, alter bacterial resistance to antibiotics, and perform a number of useful functions. Most recently, scientists have used viruses to change genes in humans as they treat a disease. So viruses are not all bad.
Thus, a virus does not directly “poison” a person. Instead it takes over a person’s cells to make copies of itself. You can’t reverse a virus or give an antidote; it is only the immune system that can stop this parasite! And, unlike the NYT authors’ theory, most people dying from COVID-19 are doing so because their immune system does not appear to be able to handle the virus.