Coronavirus is a family of viruses named for the microscopic view of crownlike spikes on their surfaces, according to the federal Centers for Disease Control and Prevention.

These viruses can cause the common cold or more severe diseases such as SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome), which have seen outbreaks in the past, according to the CDC. COVID-19 — standing for “coronavirus disease 2019” — first appeared in late 2019 in Wuhan, China.

Symptoms of COVID-19 can include fever, cough and breathing trouble. Most people develop only mild symptoms, according to Denver Public Health. But according to the CDC, some — usually those with severe underlying health conditions or older adults — develop more serious symptoms, including pneumonia, which can be fatal.

Technically, COVID-19 is caused by a virus named SARS-CoV-2.