Coronaviruses are a large group of viruses that cause diseases in animals and humans. They often circulate among animals and can sometimes evolve and infect people. In humans, the viruses can cause mild respiratory infections, like the common cold, but can lead to serious illnesses, like pneumonia.
A novel coronavirus (SARS-CoV-2) that causes the disease Coronavirus Disease 2019 (COVID-19) emerged in a seafood and poultry market in Wuhan, China in December 2019. Cases have been detected in most countries worldwide, and on March 11, 2020, the World Health Organization characterized the outbreak as a pandemic. Human-to-human transmission occurs through close contact.
Note: Information about the novel coronavirus is changing rapidly. View the latest information on the current outbreak from the Centers for Disease Control and Prevention (CDC).
What are the symptoms? How can you tell the difference between the novel coronavirus and a cold or influenza (flu)?
The symptoms are similar, including fever, cough, and shortness of breath. To diagnose a potential case, healthcare professionals may use a COVID-19 diagnostic test and/or run tests to rule out flu and other infections.
Individuals with COVID-19 have had a wide range of symptoms, ranging from mild to severe illness. Some individuals who are infected may not have symptoms, others require ventilator support, and many have died. Symptoms may appear two to 14 days after exposure to the virus and may include:
- shortness of breath or difficulty breathing
- muscle pain or body aches
- sore throat
- new loss of taste or smell
- congestion or runny nose
- nausea or vomiting
This list does not include all possible symptoms. If you develop any symptoms and think you have been exposed, call a healthcare professional immediately.
What are the symptoms in children?
Children with COVID-19 may have mild, cold-like symptoms, such as fever, runny nose, and cough, and some children experience vomiting and diarrhea. Occasionally, a child gets really sick after being infected with COVID-19. There have been some rare reports of children who have multi-system inflammatory syndrome, which has been compared to Kawasaki disease or toxic shock syndrome. The American Academy of Pediatrics advises parents to call a pediatrician if their child has any of the following symptoms:
- a fever that will not go away
- abdominal pain, diarrhea, or vomiting
- rash or changes in skin color
- pink or red eyes
- trouble breathing
- the child seems confused or overly sleepy
There is evidence that the novel coronavirus can be spread before an individual develops symptoms. This poses a problem because people who do not know they are infected may continue to go to work, school, and other public places. People who are sick and have symptoms are more likely to stay home, which means fewer opportunities for the virus to spread from one person to another. When asymptomatic transmission occurs, infection control experts and public health officials may need to take additional measures, such as social distancing, isolating patients, or using quarantines.
What should individuals do if they think they may have been infected?
Those who think they may have been exposed to coronavirus, either through travel to an affected area or close contact with someone who has a confirmed case, should call a healthcare professional if they have any of the symptoms.
It is important to call first, so that the clinic or hospital can prepare and prevent the spread of infection. Stay home and away from other people if you might have been exposed to COVID-19.
Who is at greatest risk of serious illness?
Although COVID-19 can affect anyone, individuals at greater risk of severe illness from COVID-19 include the following:
- Older adults (the older people are, the higher their risk for severe illness)
- People with chronic medical conditions like kidney disease, sickle cell disease, heart disease, type 2 diabetes, and lung disease, including chronic obstructive pulmonary disease (COPD)
- Those living in a nursing home or long-term care facility
- Obesity (body mass index [BMI] >30)
- Those who have a weakened immune system from solid organ transplant
Others who may be at risk of more severe illness include people who have asthma, high blood pressure, neurologic conditions such as dementia, cerebrovascular disease such as stroke, people who are pregnant, or those who are immunocompromised due to cancer treatment and other conditions.
CDC maintains up-to-date information on those at higher risk of serious illness from COVID-19.
How does COVID-19 affect pregnant women?
According to available data, pregnant women with COVID-19 may be more likely to experience preterm birth and are more likely to experience severe illness from COVID-19 than nonpregnant women.
Pregnant women should be mindful about reducing their risk of getting sick and ensuring that those around them also take steps to minimize risk, including proper handwashing, social distancing, and wearing a face mask in public.
Pregnant women should get vaccinated against whooping cough and influenza (flu) during each pregnancy to protect themselves and their baby, with immunity for the first few months of life. Learn more about vaccines recommended during pregnancy.
How is the novel coronavirus transmitted?
The virus that causes COVID-19 is thought to spread mainly through close contact from person-to-person (within about 6 feet). It can be spread through respiratory droplets when an infected person coughs, sneezes, or talks. Recent studies have indicated that COVID-19 may be spread by people who are not showing symptoms, which is why face masks are recommended.
What can individuals do to protect themselves?
Everyone should practice the following healthy habits to help prevent the spread of coronavirus and other respiratory viruses:
- Stay home as advised by state and local public health officials
- Wear a cloth face covering if you do go out
- Practice social distancing—stay at least 6 feet apart
- Wash hands often with soap and water for at least 20 seconds
- Avoid touching your eyes, nose, and mouth
- Cover coughs and sneezes
- Clean and disinfect common objects and surfaces daily
- If you need medical care, call first
When will vaccines for COVID-19 be widely available in the US?
All vaccines used in the US—including those being developed for COVID-19—are required to go through extensive safety testing before they are licensed by the US Food and Drug Administration (FDA) or recommended for widespread use. Vaccine safety standards will not be compromised in efforts to speed development of new vaccines for COVID-19. All necessary steps are being followed and although these steps usually happen sequentially, because of the urgency of the pandemic, certain steps are happening simultaneously. For example, manufacturers are scaling up production of vaccines that may never be licensed. If rigorous studies show that the vaccines are safe and effective, once FDA approves their licensure and they are recommended for use by the Centers for Disease Control and Prevention (CDC), vaccines will be ready to distribute across the US.
Two vaccines have received authorization for emergency use in the US for the prevention of COVID-19. The Pfizer vaccine is recommended for use in individuals age 16 years and older, and the Moderna vaccine is recommended for individuals age 18 years and older.
CDC recommends that initial limited supplies of COVID-19 vaccines be allocated to healthcare professionals and long-term care facility residents.
Globally, there are additional vaccine candidates in various stages of testing to evaluate their safety and effectiveness, including some that are based on proven technologies and some that use innovative approaches.
Will COVID-19 vaccines work against new mutations of COVID-19?
Viruses constantly mutate, and public health experts expect new variants of a virus to occur. Multiple variants of SARS-CoV-2 (the virus that causes COVID-19) have been documented in the US and globally, including:
- B117 (also known as 20B/501Y.V1, VOC 202012/01, or B.1.1.7 lineage) first emerged in the United Kingdom with an unusually large number of mutations. This variant has since been detected in the US, Canada, and numerous other countries.
- V2 (also known as 20C/501Y.V2 or B.1.351 lineage) emerged in South Africa. It shares some mutations with the B117 lineage, and cases attributed to this variant have been detected outside of South Africa.
Scientists are monitoring changes in the virus, and information about these variants is rapidly emerging. The new variants seem to spread more easily and quickly, but at this time, there is no evidence that the variants cause more severe illness or increased risk of death, or make COVID-19 vaccines less effective. Existing vaccines are expected to be effective against the variants and others that may emerge in the short term.
How can individuals who have chronic health conditions protect themselves from COVID-19?
Follow the recommended preventive steps: Stay home as advised, wear a mask, practice social distancing, and wash your hands frequently. If you have a chronic medical condition like heart disease, high blood pressure, diabetes, or lung disease, you should also:
- Continue taking your medications
- Have at least a two-week supply of all prescription (and non-prescription) drugs
- Talk to a healthcare professional to make sure you are up-to-date on all recommended vaccines, including vaccines to protect against influenza and pneumococcal disease
- Do not delay emergency care because of COVID-19. If you need emergency help, call 911.
What can people with diabetes do to protect themselves?
Individuals who have diabetes may be at greater risk of severe illness from COVID-19. If you have diabetes, it is important to continue taking your medication and insulin as usual, test your blood sugar as instructed, and keep track of the results. Stay home as advised, wear a mask, and stay at least six feet away from other people when you do go out in public. Make sure that you have easy-to-fix foods at home and at least a two-week supply of medications and diabetes management supplies.
What can people with heart disease do to protect themselves?
COVID-19 can damage the respiratory system and make it harder for the heart to function properly. If you have heart disease, it is important to take your medication exactly as prescribed, including medication to treat high cholesterol or high blood pressure. Make sure that you have at least a two-week supply of heart disease medications and continue to manage and control your blood pressure.
What can people with lung disease (like asthma) do to protect themselves?
COVID-19 can cause asthma attacks, may lead to pneumonia and other serious illnesses, and might also cause flare-ups of other chronic lung diseases. If you have lung disease, it is important to keep taking your current medications, including corticosteroids (or “steroids”), and avoid triggers that make your symptoms worse. If you have asthma, it is important to follow your asthma action plan, know how to use your inhaler, and keep your asthma under control.
Do face masks protect against COVID-19?
Face masks can help prevent an infected individual from spreading the virus. CDC recommends using breathable cloth such as 100 percent cotton, with two layers of fabric for optimal filtering. When held up to a bright light, the fabric should not let a lot of light shine through. Face coverings should:
- Fit snugly but comfortably against the side of the face
- Be secured with ties or ear loops
- Allow for breathing without restriction
- Be able to be laundered and machine dried without damage or change to shape
Face masks are not recommended for children less than two years of age or by individuals who have trouble breathing or who cannot easily remove them.
N-95 respirators should be reserved for healthcare professionals and other first responders.
Remember: Face masks are not a substitute for other preventive measures—continue to wash your hands properly, avoid touching your face, and maintain social distancing (stay at least 6 feet apart from others) in conjunction with wearing face masks in public spaces.
How long does the COVID-19 virus live on surfaces?
Initial reports indicate that the virus can persist for several hours to days in aerosols and on surfaces. It is important to clean and disinfect frequently touched surfaces each day.
What are the best cleaners to remove germs?
It is important to clean and disinfect frequently touched surfaces on a regular basis. Detergent or soap and water can be used to clean surfaces. To disinfect, use diluted household bleach solutions, alcohol solutions with at least 70% alcohol, or common household disinfectants, which are effective in killing this virus and can be used safely.
Hand hygiene is most important because hands are an important means of transmission for this virus. There are many things that we cannot control but we can wash hands and keep them away from our faces.
What tests are available to detect COVID-19?
There are currently three types of COVID-19 tests authorized by the US Food and Drug Administration (FDA):
- Molecular tests are used to detect the genetic material of SARS-CoV-2, the virus that causes COVID-19. Molecular tests are fairly accurate and can be used to diagnose the disease.
- Antigen tests are a new category of tests that can quickly detect fragments of the virus from nasal swabs. Antigen tests can provide results in minutes, but they are not as sensitive as molecular tests. Positive results from antigen tests are highly accurate, but negative results may need to be confirmed with a molecular test.
- Antibody (or serology) tests detect the body’s immune response to COVID-19 by looking for antibodies in the blood to help determine prior exposure. When the body is fighting an infection or has fought an infection, antibodies can be found in the blood. These tests do not detect the actual virus but are used to identify people who have been infected with the virus in the past.
FDA has issued emergency use authorizations for home use self-administered tests, available with a prescription or over-the-counter.
More than 300 tests have been authorized for emergency use including 235 molecular tests, 63 antibody tests, and 11 antigen tests. Accuracy varies among all of the tests. The resulting uncertainty can complicate public health decisions.
Some antibody tests have a high potential for false-negative and false-positive results. They may not be able to detect antibodies in the blood of someone who is newly infected, and they may not be able to distinguish SARS-CoV-2 from other coronaviruses. The presence of antibodies may indicate immunity from COVID-19, but that has not yet been conclusively proven; nor do scientists know the duration of protection. Although serologic tests should not be used at this time to determine if an individual is immune, these tests can help determine the proportion of a population previously infected with SARS-CoV-2 and provide information about populations that may be immune and potentially protected.
Serologic test results should not be used to make decisions about returning to school or the workplace. Additional data are needed before modifying public health recommendations based on serologic test results, including decisions on discontinuing physical distancing and using personal protective equipment.
Are there any treatments available for COVID-19?
The Food and Drug Administration has approved the antiviral drug remdesivir for treating certain patients who are hospitalized for COVID-19—specifically, adults and children age 12 years and older who weigh at least 108 pounds.
In addition, the National Institutes of Health (NIH) has developed treatment guidelines for COVID-19. The guidelines, which will be updated as experts learn more about the disease, include recommendations on antiviral drugs, as well as other treatments such as convalescent plasma and dexamethasone. Talk to your healthcare professional about treatments that may be available for you.
Stop the Spread
What is social distancing?
Deliberately increasing the physical space between people to avoid spreading illness. Staying at least 6 feet away from other people lessens your chances of catching or spreading COVID-19.
Is it safe to get routine medical care?
Many routine medical visits can be provided virtually via telemedicine. Other services, such as routine vaccinations, may be available in pharmacies or in clinics that have special immunization office hours or separate waiting rooms. It is important to make sure that you and your family members are up-to-date on all recommended vaccinations.
If you have a specific issue that needs attention, talk with a healthcare professional who can provide advice. In an emergency, call 911.
Is it dangerous to be outdoors?
Going out for a walk is good exercise and may be psychologically beneficial. But, wear a face covering and maintain at least a 6-foot distance between others. Individuals who have a chronic health condition such as heart disease, lung disease, or diabetes, as well as older adults are at greater risk for complications from COVID-19 and should be extra careful around others—either indoors or outdoors.
How do outbreaks typically end?
There are several ways that an outbreak can come to an end. The Severe Acute Respiratory Syndrome (SARS) outbreak was controlled through close coordination between public health officials and clinicians who were able to diagnose cases, isolate infected patients, trace their contacts, and implement strong infection control policies. An outbreak can also end once the virus has infected most of the people who are susceptible to it, or once there is a safe and effective vaccine available.
Responses to frequently asked questions (FAQs) about COVID-19 vaccines
Wearing a face mask shows that you care about your own health and the health of others. Face masks may not offer complete protection—you still need to stay at least 6 feet apart from others & wash your hands frequently
Annual flu vaccination can help protect individuals and prevent additional strain on an already overburdened healthcare system