COVID-19 Glossary

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elective surgeries

Procedures that are considered non-urgent and non-essential. During periods of community transmission, CDC is recommending postponing elective procedures, surgeries, and non-urgent outpatient visits. 


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.” 

essential activities

Tasks essential to maintain health and safety, such as obtaining medicine or seeing a doctor.

essential government functions

All services needed to ensure the continuing operation of the government agencies and provide for the health, safety and welfare of the public.