Updated on April 1 at 10:45 a.m. ET
Since the first U.S. case of the coronavirus was identified in Washington state on Jan. 21, health officials have identified nearly 190,000 cases across the United States and more than 4,000 deaths. By March 17, the virus had expanded its presence from several isolated clusters in Washington, New York and California to all 50 states and the District of Columbia.
Click here to see a global map of confirmed cases and deaths.
Social distancing is widely seen as the best available means to "flatten the curve of the pandemic," a phrase that epidemiologists use to describe slowing down the spread of infection. This approach can save lives by keeping local health care systems from being overwhelmed.
In response to mounting cases, states are closing schools, banning large gatherings and urging people to stay home when possible. On March 16, President Trump announced new guidelines urging Americans to avoid discretionary travel, going out to eat and gathering in groups of more than 10 people.
To avoid spreading the disease, the Centers for Disease Control and Prevention also recommends basic precautions such as hand-washing and cleaning frequently touched surfaces every day.
Globally, the respiratory disease has spread to dozens of countries and has killed several thousand people since it was first reported in Wuhan, China, in December.
Warnings issued by the CDC recommend avoiding nonessential travel to dozens of countries with outbreaks of COVID-19, including China, Iran, South Korea and many European nations. The U.S. government has banned travel from Europe, although the ban makes exceptions, including for U.S. citizens and legal permanent residents.
What is the coronavirus that causes COVID-19?
The name comes from the crownlike spikes the virus has on its surface — "corona" is Latin for "crown." Common human coronaviruses cause mild to moderate upper respiratory symptoms, including the common cold, while more severe types can cause pneumonia and death.
This particular virus, officially known as SARS-CoV-2, is only the third strain of coronavirus known to frequently cause severe symptoms in humans. The other two strains cause Middle East respiratory syndrome and severe acute respiratory syndrome.
What are the symptoms?
The primary symptoms of COVID-19 are fever, cough and shortness of breath. Some people also experience fatigue, headaches and, less frequently, diarrhea. Cases can range from mild to moderate to severe. About 80% of cases so far seem to be mild, according to the World Health Organization.
To prevent the coronavirus from spreading, the Centers for Disease Control and Prevention recommends washing hands with soap and water for at least 20 seconds or using a hand sanitizer if soap and water aren't available. The WHO says people should wear face masks only if they're sick or caring for someone who is.
What should I do if I think I'm sick?
If you think you've been exposed to the coronavirus and develop symptoms, call your doctor. Many state and local health departments have set up hotlines to answer questions, so that's another good place to start. It's important that you don't expose others. Call your doctor before you go to the doctor's office so your doctor can take necessary precautions.
How do I protect my home?
Wash your hands as soon as you walk through the door. Avoid sharing personal items such as dishes, cups and utensils. Clean and disinfect "high-touch" surfaces like door handles and cellphones every day.
How does the coronavirus spread?
The virus is thought to spread mainly between people who are in close proximity to one another: within about 6 feet. It spreads primarily through respiratory droplets that are dispersed when an infected person coughs or sneezes. Those droplets can land in the mouth or nose of someone nearby and possibly infect that person.
Does the coronavirus spread through contact with surfaces?
According to the CDC, it may be possible for people to become infected by touching a surface or object that has the virus on it and then touching their own mouth, nose or possibly eyes. But experts believe the virus spreads mostly through contact with other people.
How do I self-quarantine? And what does it mean?
The CDC has a guide for caring for yourself at home if you have a suspected or confirmed case of COVID-19.
This story was originally published on March 16, 2020.