What is novel coronavirus?
A novel coronavirus is a new coronavirus that has not been previously identified. The virus causing coronavirus disease 2019 (COVID-19), is not the same as the coronaviruses that commonly circulate among humans and cause mild illness, like the common cold.
A diagnosis with coronavirus 229E, NL63, OC43, or HKU1 is not the same as a COVID-19 diagnosis. Patients with COVID-19 will be evaluated and cared for differently than patients with common coronavirus diagnosis.
What is the source of the virus?
Coronaviruses are a large family of viruses. Some cause illness in people, and others, such as canine and feline coronaviruses, only infect animals. Rarely, animal coronaviruses that infect animals have emerged to infect people and can spread between people. This is suspected to have occurred for the virus that causes COVID-19. Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS) are two other examples of coronaviruses that originated from animals and then spread to people. More information about the source and spread of COVID-19 is available on the Situation Summary: Source and Spread of the Virus.
How does the virus spread?
This virus was first detected in Wuhan City, Hubei Province, China. The first infections were linked to a live animal market, but the virus is now spreading from person-to-person. It’s important to note that person-to-person spread can happen on a continuum. Some viruses are highly contagious (like measles), while other viruses are less so.
The virus that causes COVID-19 seems to be spreading easily and sustainably in the community (“community spread”) in some affected geographic areas. Community spread means people have been infected with the virus in an area, including some who are not sure how or where they became infected.
Learn what is known about the spread of newly emerged coronaviruses.
Can someone who has had COVID-19 spread the illness to others?
The virus that causes COVID-19 is spreading from person-to-person. Someone who is actively sick with COVID-19 can spread the illness to others. That is why CDC recommends that these patients be isolated either in the hospital or at home (depending on how sick they are) until they are better and no longer pose a risk of infecting others.
How long someone is actively sick can vary so the decision on when to release someone from isolation is made on a case-by-case basis in consultation with doctors, infection prevention and control experts, and public health officials and involves considering specifics of each situation including disease severity, illness signs and symptoms, and results of laboratory testing for that patient.
Current CDC guidance for when it is OK to release someone from isolation is made on a case by case basis and includes meeting all of the following requirements:
- The patient is free from fever without the use of fever-reducing medications.
- The patient is no longer showing symptoms, including cough.
- The patient has tested negative on at least two consecutive respiratory specimens collected at least 24 hours apart.
Someone who has been released from isolation is not considered to pose a risk of infection to others.
Can someone who has been quarantined for COVID-19 spread the illness to others?
Quarantine means separating a person or group of people who have been exposed to a contagious disease but have not developed illness (symptoms) from others who have not been exposed, in order to prevent the possible spread of that disease. Quarantine is usually established for the incubation period of the communicable disease, which is the span of time during which people have developed illness after exposure. For COVID-19, the period of quarantine is 14 days from the last date of exposure, because 14 days is the longest incubation period seen for similar coronaviruses. Someone who has been released from COVID-19 quarantine is not considered a risk for spreading the virus to others because they have not developed illness during the incubation period.
What is community spread?
Community spread means people have been infected with the virus in an area, including some who are not sure how or where they became infected.
How can I help protect myself?
Visit the COVID-19 Prevention and Treatment page to learn about how to protect yourself from respiratory illnesses, like COVID-19.
What should I do if I had close contact with someone who has COVID-19?
There is information for people who have had close contact with a person confirmed to have, or being evaluated for, COVID-19 available online.
Who is at higher risk for serious illness from COVID-19?
Early information out of China, where COVID-19 first started, shows that some people are at higher risk of getting very sick from this illness including older adults, and people who have serious chronic medical conditions like heart disease, diabetes, and lung disease.
What should people at higher risk of serious illness with COVID-19 do?
If you are at higher risk of getting very sick from COVID-19, you should: stock up on supplies; take everyday precautions to keep space between yourself and others; when you go out in public, keep away from others who are sick; limit close contact and wash your hands often; and avoid crowds, cruise travel, and non-essential travel. If there is an outbreak in your community, stay home as much as possible. Watch for symptoms and emergency signs. Watch for symptoms and emergency signs. If you get sick, stay home and call your doctor. More information on how to prepare, what to do if you get sick, and how communities and caregivers can support those at higher risk is available on People at Risk for Serious Illness from COVID-19.
Does CDC recommend the use of facemask to prevent COVID-19?
CDC does not recommend that people who are well wear a facemask to protect themselves from respiratory illnesses, including COVID-19. You should only wear a mask if a healthcare professional recommends it. A facemask should be used by people who have COVID-19 and are showing symptoms. This is to protect others from the risk of getting infected. The use of facemasks also is crucial for health workers and other people who are taking care of someone infected with COVID-19 in close settings (at home or in a health care facility).
What are the symptoms and complications that COVID-19 can cause?
Current symptoms reported for patients with COVID-19 have included mild to severe respiratory illness with fever1, cough, and difficulty breathing. Read about COVID-19 Symptoms.
Should I be tested for COVID-19?
If you develop symptoms such as fever, cough, and/or difficulty breathing, and have been in close contact with a person known to have COVID-19 or have recently traveled from an area with ongoing spread of COVID-19, stay home and call your healthcare provider. Older patients and individuals who have severe underlying medical conditions or are immunocompromised should contact their healthcare provider early, even if their illness is mild. If you have severe symptoms, such as persistent pain or pressure in the chest, new confusion or inability to arouse, or bluish lips of face, contact your healthcare provider or emergency room and seek care immediately. Your doctor will determine if you have signs and symptoms of COVID-19 and whether you should be tested.