What's the difference between isolation and quarantine? How exactly does testing work? With the fast-moving pace of news surrounding the global coronavirus outbreak comes a slew of scientific and health-related terms and concepts.
We've gathered up some of the more common ones for a quick explainer.
Coronaviruses: One of the biggest families of viruses. (See this WIRED article for a rundown of just how many there are). Seven of them are known to cause human illness. They cause things like the common cold, but three of them can cause more serious illnesses: Middle East respiratory syndrome (MERS), the 2003 severe acute respiratory syndrome (SARS) epidemic, and the current COVID-19 pandemic.
COVID-19: The name of the disease caused by the virus known as SARS-CoV-2, Wuhan coronavirus, the "novel" or "new" coronavirus, or just "the coronavirus," which is now circulating around the globe. COVID-19 is a shortened form of the term "coronavirus disease 2019."
SARS-CoV-2: The name of the virus itself. Confusingly, it was previously called 2019-nCov (which just meant "2019 new coronavirus"). SARS-CoV-2 basically means "severe acute respiratory syndrome caused by coronavirus number 2." Number 1 was the coronavirus that caused the 2003 SARS epidemic.
Community spread or community transmission: This means a person in Colorado got the virus from another person in Colorado, rather than from international travel. On March 11, the health department in Colorado announced that "limited community spread" is occuring in the state.
Social distancing: Avoiding places where people gather, including public transportation. It can also mean keeping a space of about six feet between yourself and others.
Isolation: This is the term used when someone is actually sick with the virus, and stays home so they don't spread it to others.
Quarantine: This is the term used when someone has probably been exposed to the virus, but might not actually have it. They stay home for 14 days because that's the time period during which where symptoms would appear if they did actually get the virus.
Incubation period: The amount of time it could take between catching the virus and showing symptoms of it. For the novel coronavirus, it's considered to be two to 14 days.
Epidemic: An excess of cases of an illness over a certain region, according to the World Health Organization.
Pandemic: When an epidemic goes global. On March 11, the World Health Organization declared the current outbreak to be a pandemic. "This is the first pandemic caused by coronavirus," said WHO director-general Tedros Adhanom Ghebreyesus. As NPR has reported, the last declared pandemic was the 2009 "swine flu."
Testing: The CDC test to determine if someone is positive involves something called "real time RT-polymerase chain reaction." As NPR has reported, the method looks for pieces of virus in a person's bodily fluids. For COVID-19, that usually means swabbing the nose and/or throat. The test only works when someone is actively ill. The CDC says it's working on another test that would show if someone had been exposed to coronavirus in the past, maybe without even knowing it. And companies are working on developing tests, too.
Presumptive positive or presumed positive: When the state runs a test and it comes out positive. It isn't considered "confirmed" until the CDC has double-checked the result.
Exponential spread: The spiral where the more people get a disease, the faster it spreads, and the faster it spreads, the more people get it (there's a reason we call internet hits "viral" rather than "bacterial" or "fungal"). As the Washington Post has written, "When something dangerous is growing exponentially, everything looks fine until it doesn't." The word "tsunami" comes up a lot in describing the growth of coronavirus cases — nothing at first, and then suddenly a big rush overloading hospitals. The public health goal right now is to keep cases from spiking quite so dramatically and instead spread the cases out over time, so health care systems can treat people who need care.
More terms can be found in this NPR post.