science environment

A Glossary Of Coronavirus Terms, From ARDS To Zoonotic

By Erin Ross (OPB)
March 10, 2020 10:15 p.m.

There's a lot of medical and scientific jargon out there when the coronavirus is being discussed. And while we try to translate jargon into plain language for our news articles, we know you might encounter it as you read more about coronavirus.

That's why we've compiled this glossary. It covers many of the words you'll encounter in the news, broadcast interviews with experts and in more scientific writing. If there's a word you've run into that should be in here, let us know and we can update the story.


Glossary Index

0 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z



An old name for the virus that causes COVID-19. It is now called SARS-CoV-2.


Acute Respiratory Distress Syndrome (ARDS) 

An often-fatal failure of the respiratory system. When an illness is called “acute,” it means it comes on really quickly, which makes getting treatment fast necessary. People with ARDS breathe rapidly, are short of breath and might have bluish skin. ARDS is a potential complication of COVID-19, and it can happen very quickly. If you are experiencing those symptoms, go to the doctor immediately.


The tiny air-filled sacs that make up our lungs. Lungs aren’t like big balloons. They’re more like sponges made up of millions of tiny balloons. There are cells in our alveoli that make a protein that lubricates our lungs and keeps them happy. The COVID-19 virus binds to those cells. Researchers think that may be why the virus is so much more severe than the cold-causing coronavirus.

antiretroviral drugs

These are drugs that attack retroviruses like HIV. Antiretrovirals block or slow down an enzyme that retroviruses use to chop up DNA. If a virus can't chop DNA, it can't make more of itself and can't make you sick. Because coronavirus also uses this enzyme, there was some hope that already existing antiretrovirals could fight the COVID-19 virus. Unfortunately, there's little evidence that it works on coronavirus. But hope is not lost — there are other antivirals out there! There are currently clinical trials investigating if the antiviral drug remdesivir works against coronavirus.


Kills bacteria — but not viruses. Antibacterial soaps are no more effective than regular soap against viruses like the coronavirus.


A medication that kills bacteria. Antibiotics do not work on viruses, but they are an important part of treating secondary infections like bacterial pneumonia, which can occur as a side-effect of COVID-19.


Antimicrobial products kill most microbes, like viruses, bacteria, and fungi. Hand sanitizer that’s at least 60% isopropyl alcohol is antimicrobial. Some hand sanitizers are only antibacterial and will not protect against coronavirus.


When you aren’t showing symptoms. There is some evidence for asymptomatic spread of COVID-19, but those may be cases with mild symptoms that went unreported.

Return To Index


case fatality rate (CFR)

The number of sick people who die from a specific disease. You calculate case fatality ratio by taking the number of people who have died from a disease and dividing it by the number of people who got that disease.

A CFR can change over space and time. Estimates of the case fatality rate for COVID-19 have varied from .7% to 4% or occasionally higher, depending on when the rate was sampled, how it was sampled and the quality of care those people received. Right now, the WHO says the global case fatality rate is about 3.4%. This number will continue changing as more people get infected and the disease spreads to countries with better and worse health care.


Stands for the Centers for Disease Control and Prevention. The CDC is the U.S. agency that tracks diseases across the country, and is responsible for confirming COVID-19 cases. The main lab is in Atlanta, but the agency has other labs around the country where the study of deadly diseases and the search for cures take place.

circulatory system

The system that moves blood through your body. Blood transports nutrients and oxygen.

clinical trial

A designed trial to test the effectiveness of a medication or treatment. Clinical trials include “controls.” A control is a person or group or lab specimen that doesn’t receive the new treatment. The goal is to see if the treatment really works, or if it’s just a placebo effect or caused by something else.

community transmission

When a virus is being passed from person to person in a community and starts appearing in people who aren’t known to have contact with an infected person. Many of the people sick in Oregon got their virus from community transmission. It is concerning because there are a chunk of cases health authorities do not know about.

confirmed case

A coronavirus case that has been confirmed by the CDC.


A group of RNA viruses that circulate in animals and humans. In humans, they cause respiratory illnesses, which means they cause symptoms in the lungs, throat, and airways.


The disease caused by SARS-CoV-2.

CT scan

“Computer Tomography scan.” It’s an advanced type of X-ray that makes a more detailed image. CT scans can help identify suspected coronavirus patients.

Return To Index



Deoxyribonucleic acid. Many of our genes are stored in DNA. Some are stored in RNA. DNA is a sort of blueprint. It tells our bodies how to grow, assemble themselves, and go about the business of living. Coronaviruses are RNA viruses, so they don't contain DNA

Return To Index



An infection that causes the brain to inflame. It can be extremely dangerous and fatal. Coronaviruses are known to infect the brain, spine and nervous system in lab animals. One case of viral encephalitis was linked to COVID-19, but it is not a major concern with the virus.


An enzyme is a molecule made up of different proteins. They’re molecules that our bodies use to do things. The enzyme myosin makes muscles contract, and the enzyme insulin tells our blood when to absorb sugar. Viruses use enzymes to hijack our cells and make copies of themselves. Many antiviral treatments work by targeting enzymes: to fight a viral infection, you take away the tools a virus needs to make more of itself.


A large outbreak of disease, taking place over a short period of time. An epidemic might infect a region or a country. Epidemics usually happen when a new disease emerges or when something happens to make people less immune to a disease. A pandemic is an epidemic that spreads to multiple large regions, like several continents or countries.


The study of how infectious diseases spread, occur, and are controlled. John Snow (not to be confused with the character Jon Snow of "Game of Thrones" fame) is considered the founder of modern epidemiology. He famously traced a 19th-century cholera epidemic to a contaminated water pump and the pump handle. He chlorinated the water and removed the pump handle, and the disease ended. Today, sometimes epidemiologists talk about tracing modern diseases back to the metaphorical “Pump Handle.” We still haven’t found it for coronavirus.

Return To Index



An online database of genetic sequences from around the world and maintained by the national library of medicine.

Return To Index


in vitro

A lab test done on cells, not living things. We do in vitro tests on drugs, diseases and chemicals to see how they impact human cells.

in vivo

A lab test on a living organism, whether that’s a plant or an animal or something else. Drugs are usually tested in vivo to make sure they’re safe and that they work.

incubation period

The amount of time it takes for an infected person to start showing symptoms. Most people develop COVID-19 symptoms by day 12, but some people will take longer.


An immune system that isn’t functioning correctly. You can be immunocompromised by diseases like AIDS or taking some anti-cancer drugs, but you can also be immunocompromised by losing sleep, not drinking enough water and eating poorly. Pregnant women aren’t considered immunocompromised, but changes to their immune system can make them more susceptible to some diseases.


People with immune systems that are (usually artificially) weakened. People with organ transplants take immunosuppressants to stop their immune systems from attacking the organs. Immunosuppressed people are also immunocompromised.

Return To Index



Middle East Respiratory Syndrome. Another type of coronavirus, transmitted from camels. MERS is more deadly than COVID-19. It causes noticeable symptoms in most people, so it’s easier to track the virus.

morbidity rate

The number of people who will get sick from a particular cause in a particular population over a certain period of time. To calculate the morbidity rate you would divide the number of sick people in a population by the number of healthy people.

mortality rate

The number of deaths from a particular cause in a particular population over a certain period of time. To calculate the mortality rate, you would divide the number of deaths by the number of sick and healthy people in a population.

Return To Index



novel coronavirus (nCoV)

Any new coronavirus that hasn't been studied yet or that has just emerged. When SARS-CoV-2 was first found, it was called 2019-nCoV. The SARS-CoV-2 virus causes the disease, which is called COVID-19.

Return To Index



An outbreak is when a disease spreads quickly in a group of people (or animals or plants or ...) in one place at one time. When a bunch of people in one town get food poisoning, that’s an outbreak. An epidemic is a really big outbreak, but still just one place at one time.

Return To Index



An epidemic that has spread to multiple continents or countries. On March 11, after extensive COVID-19 spread on multiple continents, the WHO officially declared the coronavirus outbreak a global pandemic.


Stands for Powered Air-Purifying Respirator. They’re the giant full-body suits and helmets healthcare workers wear to treat people quarantined with infectious diseases.


A bacteria, microbe, parasite, fungus, virus or other organism that causes a disease.

personal protective equipment (PPE)

Equipment such as masks and gloves that doctors and nurses wear to protect themselves from diseases.


An infection that causes the tiny air sacs in lungs, called alveoli, to get inflamed and fill with fluid, like mucus or pus. It can be caused by bacteria or viruses. Viral pneumonia can leave the body open for infection from bacterial pneumonia. Right now, bacterial pneumonia is a major complication of COVID-19.

preexisting conditions

Preexisting conditions are health conditions someone already has that could make a coronavirus infection worse. Lung disease, asthma and heart disease are preexisting conditions


A scientific study that is posted online before it has gone through peer-review. Some preprints are good; some are bad. There’s very little quality control. Because peer-review can take a long time, many studies published on coronavirus will be released as preprints. Make sure any preprint you read or share is vetted by other scientists or journalists before sharing to prevent the spread of misinformation.

presumptive case

A coronavirus case identified by a testing organization like the Oregon Health Authority. Although other groups can do tests for coronavirus they won’t be considered a confirmed case until the CDC checks the data.


Person Under Investigation. These are people with COVID-19-like symptoms who are not confirmed to have the virus. PUIs can be individuals who had contact with a confirmed case and are displaying some symptoms or they can be people who were hospitalized with severe pneumonia without a different explanation.


Person under monitoring. A individual who does not have COVID-19 symptoms but who has been in contact with someone who is presumed or confirmed to have the virus. A PUM is “monitored” until they’ve gone a period of time without developing symptoms.


Something involving lungs. A pulmonary disease is a lung disease.

Return To Index



A restriction on people who aren’t ill but who are presumed to have been exposed to a contagious disease. Individuals, groups or communities can be subject to quarantine. It can be voluntary or mandatory and can take place at home or at a designated facility.

Return To Index



In epidemiology, an R0 is a measure of transmission. It basically represents the average number of people that one infected person will, in turn, infect. Based on current information, coronavirus has an R0 somewhere between 2 and 3, so the average infected person will pass the virus on to two or three more people. That makes it more contagious than the flu, which has an R0 of about 1.5. Measles, one of the most contagious viruses, has an R0 of about 15.


An antiviral that may work against coronavirus. It is currently in clinical trials but for bureaucratic and scientific reasons those trials may not be considered valid in the U.S.

respiratory illness

A disease that impacts lungs, throat and airways. Respiratory illnesses primarily cause coughing, fever and can lead to severe pneumonia. Most are spread in respiratory droplets, which are virus-filled drops of water we shoot out when we cough and sneeze. Although respiratory illnesses attack airways, they can ultimately damage a number of other organs.

respiratory system

The entire system that lets you breathe. Not just your lungs, but your nose, your airways, your trachea, your mouth and your diaphragm are all a part of the respiratory system.


Ribonucleic acid; a type of genetic material. Humans, plants, animals, bacteria and some viruses have both DNA and RNA. In humans, DNA stores the information that says how to code our body, while RNA reads that DNA and helps make the proteins and enzymes that make things happen. Sometimes, the RNA can make things happen on its own, too. Coronavirus is an RNA virus or ribovirus, which means that drugs that treat it need to somehow block the virus’ RNA from invading our cells.


A way to sequence DNA and RNA in near real time. Most tests for coronavirus are RT-PCR tests. These tests have a high rate of false negatives but a low rate of false positives, so most people are tested twice.

Return To Index



Another coronavirus that caused an outbreak in the mid-2000s. Severe acute respiratory syndrome (SARS) was not as infectious as SARS-CoV-2, but it did have a much higher fatality rate.


The novel coronavirus that was first noticed in Wuhan, China, and is responsible for the current outbreak. The disease it causes is called COVID-19.

secondary infection

A separate, unrelated infection caused by another disease. Bacterial pneumonia is a secondary illness that can be caused by COVID-19.


Voluntarily staying home if you think you are sick.

serological survey

A survey that looks for immune cells in a person’s blood. Serological tests are a way to tell if someone was once infected with a disease and then got better. Once we do more serological tests, we’ll have a better idea of how far COVID-19 spread and how deadly it really is. That’s because serological tests can identify low-symptom people who haven’t been previously identified by doctors.

situation report

The World Health Organization releases daily situation reports that track the spread of and fight against coronavirus across the world.

social distancing

A preventive measure that encourages avoiding large crowds or small gatherings in tight places, keeping a distance from others and, for those with underlying health conditions, staying home.

suspected case

People with COVID-19-like symptoms who are not confirmed to have the virus.

Return To Index



The spread of disease. A disease can be transmitted from person to person, from person to animal to person or by the environment (think: giardia in water.) Coronaviruses are transmitted in respiratory droplets, which are drops of water and mucus that come out of our lungs when we cough and sneeze. They can also contaminate door handles and surfaces.

Return To Index



A measure of how much damage a germ does. Virulence can also refer to chemicals and toxins. COVID-19 is more virulent than the flu but less virulent than SARS and MERS.


A type of germ or microbe. Viruses are not considered alive because they don’t have the tools they need to replicate on their own. The flu, COVID-19, Zika and Ebola are all caused by viruses. Viruses cannot be treated with antibiotics.

Return To Index


World Health Organization

A global organization that directs international health for the United Nations. They study communicable and non-communicable diseases, illnesses caused by environmental factors like pollution and illnesses caused by germs. They are coordinating the global response to COVID-19 and tracking its spread.

Return To Index



This is a tough one. Zinc is a mineral that may have antiviral properties. Some studies suggest that zinc can reduce the length and severity of a cold if you take it within the first 24 hours of a disease. But some people have criticized those studies and others haven’t found an association. The Mayo Clinic does not recommend the use of zinc to treat colds, or any other virus. If you do take zinc, be sure not to take too much, and avoid zinc nasal sprays, which can cause nerve damage and make you permanently lose your sense of smell.


A disease that infects humans but originally came from other animals. The genetic sequence of the COVID-19 virus is similar to a coronavirus found in bats, so that may be where this disease originated. It may also have passed through other species on the way to humans, like snakes. Some zoonotic diseases, such as Zika and malaria, cannot be passed from person to person without an animal host.

Return To Index