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Researchers Douglas Anderson, Dragony Fu, and Lynne Maquat are among the scientists at the University of Rochester who study the RNA of viruses to better understand how RNAs work and how they are involved in diseases. (University of Rochester photos / Matt Wittmeyer / J. Adam Fenster)

How does coronavirus infect humans?

In mammals, such as humans, DNA contains genetic instructions that are transcribed—or copied—into RNA. While DNA remains in the cell's nucleus, RNA carries the copies of genetic information to the rest of the cell by way of various combinations of amino acids, which it delivers to ribosomes. The ribosomes link the amino acids together to form proteins that then carry out functions within the human body.

Many diseases occur when these gene expressions go awry.

COVID-19, short for "coronavirus disease 2019," is caused by the novel coronavirus SARS-CoV-2. Like many other viruses, SARS-CoV-2 is an RNA virus. This means that, unlike in humans and other mammals, the genetic material for SARS-CoV-2 is encoded in RNA. The viral RNA is sneaky: its features cause the protein synthesis machinery of our cells to mistake it for RNA produced by our own DNA.

While SARS-CoV-2 is a new coronavirus, "it likely replicates and functions similar to related coronaviruses that infect animals and humans," says Douglas Anderson, an assistant professor of medicine in the Aab Cardiovascular Research Institute and a member of the Center for RNA Biology, who studies how RNA mutations can give rise to human disease.

A graphic created by the New York Times illustrates how the coronavirus that causes COVID-19 enters the body through the nose, mouth, or eyes and attaches to our cells. Once the virus is inside our cells, it releases its RNA. Our hijacked cells serve as virus factories, reading the virus's RNA and making long viral proteins to compromise the immune system. The virus assembles new copies of itself and spreads to more parts of the body and—by way of saliva, sweat, and other bodily fluids—to other humans.

"Once the virus is in our cells, the entire process of infection and re-infection depends on the viral RNA," Maquat says.