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Confused by coronavirus terms? Here’s a glossary

Items from a Covid-19 test kit.Michael Nagle/Bloomberg

A lot of terms are getting thrown around in news reports about coronavirus. Here’s a glossary of some of the terms you may have heard recently:

Community spread means the spread of a disease for which the source of infection is unknown, according to the US Centers for Disease Control and Prevention. In other words, cases are arising that cannot be traced to travel to another country or to contact with a person known to be infected.

Social distancing refers to various methods used to keep people from being close together so the spread of the disease can be reduced. Social distancing measures can include limiting large gatherings, canceling events, and closing buildings. Dr. Kathryn Stephenson of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center noted that the virus seems to spread most consistently when people are within six feet of each other.


Containment is the strategy of trying to check the spread of a disease, to simply shut it down. “Your hope, your goal, is to completely stop transmission of the virus amongst your local population so that, after some period of time, you don’t have to worry about it any more," Stephenson said.

Mitigation is the strategy used once there is community spread of a disease. “Once you have community spread and it’s no longer possible to fully understand who has contacted who — you have to switch to mitigation,” Stephenson said. Mitigation includes social distancing and other public health directives like the ones we’re all familiar with now, such as washing your hands, avoiding touching your face, and staying home when you’re sick.

Contact tracing is the process that happens when public health workers interview a person who is ill with an infectious disease to try to trace who they’ve been in contact with, in an effort contain the spread.


Self-quarantine is when a healthy person who has been exposed to the disease but does not have a confirmed case voluntarily removes themself from contact with other people.

Isolation is when a person who has a known infection stays alone, away from the public.

Shedding is a term used when infectious virus particles leave a person’s body. It can lead to the person being contagious.

Covid-19 is the specific name given to the disease caused by the new coronavirus first identified in China in late 2019. The “Co” and “vi” stand for coronavirus, the "d" is for disease, and the “19” is for 2019. The virus itself is actually called SARS-cov-2.

Incubation period is the time between infection and the appearance of signs or symptoms of an illness.

Epidemic, outbreak, and pandemic — An epidemic is “an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area,” according to the CDC. An outbreak is used for a more limited geographic area. A pandemic is an “epidemic that has spread over several countries or continents, usually affecting a large number of people." The World Health Organization on Wednesday declared a pandemic, acknowledging what has seemed clear for some time — the virus will likely spread to all countries on the globe.

Jeremiah Manion of the Globe staff contributed to this report. Material from The Associated Press was used in this report.


Martin finucane can be reached at martin.finucane@globe.com.