Editor’s note: For the latest updates on the 2020 coronavirus outbreak, see our news coverage.
What Is COVID-19?
COVID-19 is a disease caused by SARS-CoV-2 that can trigger what doctors call a respiratory tract infection. It can affect your upper respiratory tract (sinuses, nose, and throat) or lower respiratory tract (windpipe and lungs).
It spreads the same way other coronaviruses do, mainly through person-to-person contact. Infections range from mild to deadly.
SARS-CoV-2 is one of seven types of coronavirus, including the ones that cause severe diseases like Middle East respiratory syndrome (MERS) and sudden acute respiratory syndrome (SARS). The other coronaviruses cause most of the colds that affect us during the year but aren’t a serious threat for otherwise healthy people.
Is there more than one strain of SARS-CoV-2?
It’s normal for a virus to change, or mutate, as it infects people. A Chinese study of 103 COVID-19 cases suggests the virus that causes it has done just that. They found two strains, which they named L and S. The S type is older, but the L type was more common in early stages of the outbreak. They think one may cause more cases of the disease than the other, but they’re still working on what it all means.
How long will the coronavirus last?
It’s too soon to tell how long the pandemic will continue. It depends on many things, including researchers’ work to learn more about the virus, their search for a treatment and a vaccine, and the public’s efforts to slow the spread.
More than 100 vaccine candidates are in various stages of development and testing. This process usually takes years. Researchers are speeding it up as much as they can, but it still might take 12 to 18 months to find a vaccine that works and is safe.
Symptoms of COVID-19
The main symptoms include:
- Shortness of breath
- Trouble breathing
- Chills, sometimes with shaking
- Body aches
- Sore throat
- Loss of smell or taste
The virus can lead to pneumonia, respiratory failure, septic shock, and death. Many COVID-19 complications may be caused by a condition known as cytokine release syndrome or a cytokine storm. This is when an infection triggers your immune system to flood your bloodstream with inflammatory proteins called cytokines. They can kill tissue and damage your organs.
If you notice the following severe symptoms in yourself or a loved one, get medical help right away:
- Trouble breathing or shortness of breath
- Ongoing chest pain or pressure
- New confusion
- Can’t wake up fully
- Bluish lips or face
Strokes have also been reported in some people who have COVID-19. Remember FAST:
- Face. Is one side of the person’s face numb or drooping? Is their smile lopsided?
- Arms. Is one arm weak or numb? If they try to raise both arms, does one arm sag?
- Speech. Can they speak clearly? Ask them to repeat a sentence.
- Time. Every minute counts when someone shows signs of a stroke. Call 911 right away.
If you’re infected, symptoms can show up in as few as 2 days or as many as 14. It varies from person to person.
According to researchers in China, these were the most common symptoms among people who had COVID-19:
- Fever 99%
- Fatigue 70%
- Cough 59%
- Lack of appetite 40%
- Body aches 35%
- Shortness of breath 31%
- Mucus/phlegm 27%
Some people who are hospitalized for COVID-19 have also have dangerous blood clots, including in their legs, lungs, and arteries.
What to do if you think you have it
If you live in or have traveled to an area where COVID-19 is spreading:
- If you don’t feel well, stay home. Even if you have mild symptoms like a headache and runny nose, stay in until you’re better. This lets doctors focus on people who are more seriously ill and protects health care workers and people you might meet along the way. You might hear this called self-quarantine. Try to stay in a separate room away from other people in your home. Use a separate bathroom if you can.
- Call the doctor if you have trouble breathing. You need to get medical help as soon as possible. Calling ahead (rather than showing up) will let the doctor direct you to the proper place, which may not be your doctor’s office. If you don’t have a regular doctor, call your local board of health. They can tell you where to go for testing and treatment.
- Follow your doctor’s advice and keep up with the news on COVID-19. Between your doctor and health care authorities, you’ll get the care you need and information on how to prevent the virus from spreading.
For more information about COVID-19, see our FAQ.
How do I know if it’s COVID-19, a cold, or the flu?
Symptoms of COVID-19 can be similar to a bad cold or the flu. Your doctor will suspect COVID-19 if:
- You have a fever and a cough.
- You live in an area with the virus or have traveled to places where it has spread.
Cold vs. Flu vs.
Allergies vs. COVID-19
(can range from moderate to severe)
High (100-102 F), Can last 3-4 days
Can be present
General aches, pains
Usual, often severe
Can be present
Intense, can last up to 2-3 weeks
Can be present
Usual (starts early)
Can be present
Has been reported
Has been reported
Has been reported
Mild to moderate
Common, can become severe
Shortness of breath
Rare, except for those with allergic asthma
In more serious infections
Loss of smell and taste
Has been reported
Sometimes in children
Has been reported
Is COVID-19 worse than the flu?
Unlike the flu, a lot of people aren’t immune to the coronavirus because it’s so new. If you do catch it, the virus triggers your body to make things called antibodies. Researchers are looking at whether they give you protection against catching it again.
The coronavirus also appears to cause higher rates of severe illness and death than the flu. But the symptoms themselves can vary widely from person to person.
Is COVID-19 seasonal like the flu?
A few lab studies have found that higher temperatures and humidity levels might help slow the spread of the coronavirus. But experts advise caution and say weather changes won’t matter without thorough public health efforts. Also, past flu pandemics have happened year-round.
Causes of the New Coronavirus
Researchers aren’t sure what caused it. There’s more than one type of coronavirus. They’re common in people and in animals including bats, camels, cats, and cattle. SARS-CoV-2, the virus that causes COVID-19, is similar to MERS and SARS. They all came from bats.
Coronavirus Risk Factors
Anyone can get COVID-19, and most infections are usually mild, especially in children and young adults. But if you aren’t in an area where COVID-19 is spreading, haven’t traveled from an area where it’s spreading, and haven’t been in contact with someone who has it, your risk of infection is low.
People over 65 are most likely to get a serious illness, as are those who live in nursing homes or long-term care facilities, who have weakened immune systems, or who have medical conditions including:
- High blood pressure
- Heart disease
- Lung disease
- Kidney disease that needs dialysis
- Cancer treatment, especially chemotherapy
- Liver disease
- Cigarette smoking
Some children and teens who are in the hospital with COVID-19 have an inflammatory condition that doctors are callingmultisystem inflammatory syndrome in children, or MIS-C. Doctors think it may be linked to the virus. It causes symptoms similar to those of toxic shock and of Kawasaki disease, a condition that causes inflammation in kids’ blood vessels.
How does the coronavirus spread?
SARS-CoV-2, the virus, mainly spreads from person to person.
Most of the time, it spreads when a sick person coughs or sneezes. They can spray droplets as far as 6 feet away. If you breathe them in or swallow them, the virus can get into your body. Some people who have the virus don’t have symptoms, but they can still spread the virus.
You can also get the virus from touching a surface or object the virus is on, then touching your mouth, nose, or possibly your eyes. Most viruses can live for several hours on a surface that they land on. A study shows that SARS-CoV-2 can last for several hours on various types of surfaces:
- Copper: 4 hours
- Cardboard: up to 24 hours
- Plastic or stainless steel: 2 to 3 days
That’s why it’s important to disinfect surfaces to get rid of the virus.
Some dogs and cats have tested positive for the virus. A few have shown signs of illness. But there’s no evidence that humans can catch this coronavirus from an animal.
What is community spread?
Doctors and health officials use this term when they don’t know the source of the infection. With COVID-19, it usually refers to someone who gets the virus even though they haven’t been out of the country or haven’t been exposed to someone who’s traveled abroad or who has COVID-19.
In February 2020, the CDC confirmed a COVID-19 infection in California in a person who had not traveled to an affected area or been exposed to someone with the disease. This marked the first instance of community spread in the U.S. It’s likely that person was exposed to someone who was infected but didn’t know it.
How fast is it spreading?
The number of people infected by SARS-CoV-2 changes every day. See our news story for the latest updates on this developing story.
How contagious is the coronavirus?
The transmission rate is relatively high. Early research has estimated that one person who has it can spread it to between 2 and 2.5 others. One study found that the rate was higher, with one case spreading to between 4.7 and 6.6 other people. By comparison, one person who has the seasonal flu will pass it to between 1.1 and 2.3 others.
We can work to lower the transmission rate by washing hands often, keeping common surfaces clean, limiting contact with other people, and wearing cloth face masks when we can’t stay 6 feet away from others.
Can coronavirus be transmitted through groceries, packages, or food?
You’re much more likely to get COVID-19 from another person than from packages, groceries, or food. If you’re in a high-risk group, stay home and use a delivery service or have a friend shop for you. Have them leave the items outside your front door, if you can. If you do your own shopping, try to stay at least 6 feet away from other shoppers. That isn’t always possible, so wear a cloth face mask, too.
Wash your hands for at least 20 seconds before and after bringing things into your home. The coronavirus can linger on hard surfaces, so clean and disinfect countertops and anything else your bags have touched. You can wipe down plastic, metal, or glass packaging with soap and water if you want.
There’s no evidence that anyone has gotten COVID-19 from food or food containers.
Call your doctor or local health department if you think you’ve been exposed and have symptoms like:
- Fever of 100 F or higher
- Trouble breathing
In most states, decisions about who gets tested for COVID-19 are made at the state or local level.
A swab test is the most common method. It looks for signs of the virus in your upper respiratory tract. The person giving the test puts a swab up your nose to get a sample from the back of your nose and throat. That sample usually goes to a lab that looks for viral material, but some areas may have rapid tests that give results in as little as 15 minutes.
If there are signs of the virus, the test is positive. A negative test could mean there is no virus or there wa
sn’t enough to measure. That can happen early in an infection. It usually takes 24 hours to get results, but the tests must be collected, stored, shipped to a lab, and processed.
The FDA is granting emergency use authorizations for tests that don’t have full approval yet. These include a home nasal swab test, a home saliva test, and tests that check your blood for things called antibodies. Your immune system makes antibodies in response to an infection.
A swab test can only tell whether you have the virus in your body at that moment. But an antibody test can show whether you’ve ever been exposed to the virus, even if you didn’t have symptoms. This is important in officials’ efforts to learn how widespread COVID-19 is. In time, it might also help them figure out who’s immune to the virus.
The FDA is working with laboratories across the country to develop more tests.
Take these steps:
- Wash your hands often with soap and water or clean them with an alcohol-based sanitizer. This kills viruses on your hands.
- Practice social distancing. Because you can have and spread the virus without knowing it, you should stay home as much as possible. If you do have to go out, stay at least 6 feet away from others.
- Cover your nose and mouth in public. If you have COVID-19, you can spread it even if you don’t feel sick. Wear a cloth face covering to protect others. This isn’t a replacement for social distancing. You still need to keep a 6-foot distance between yourself and those around you. Don’t use a face mask meant for health care workers. And don’t put a face covering on anyone who is:
- Under 2 years old
- Having trouble breathing
- Unconscious or can’t remove the mask on their own for other reasons
- Don’t touch your face. Coronaviruses can live on surfaces you touch for several hours. If they get on your hands and you touch your eyes, nose, or mouth, they can get into your body.
- Clean and disinfect. You can clean first with soap and water, but disinfect surfaces you touch often, like tables, doorknobs, light switches, toilets, faucets, and sinks. Use a mix of household bleach and water (1/3 cup bleach per gallon of water, or 4 teaspoons bleach per quart of water) or a household cleaner that’s approved to treat SARS-CoV-2. You can check the Environmental Protection Agency (EPA) website to see if yours made the list. Wear gloves when you clean and throw them away when you’re done.
There’s no proof that herbal therapies and teas can prevent infection.
COVID-19 preparation tips
In addition to practicing the prevention tips listed above, you can:
- Meet as a household or larger family to talk about who needs what.
- If you have people at a higher risk, ask their doctor what to do.
- Talk to your neighbors about emergency planning. Join your neighborhood chat group or website to stay in touch.
- Find community aid organizations that can help with health care, food delivery, and other supplies.
- Make an emergency contact list. Include family, friends, neighbors, carpool drivers, doctors, teachers, employers, and the local health department.
- Choose a room (or rooms) where you can keep someone who’s sick or who’s been exposed separate from the rest of you.
- Talk to your child’s school about keeping up with assignments.
- Set yourself up to work from home if your office is closed.
- Reach out friends or family if you live alone. Make plans for them to check on you by phone, email, or video chat.
Can a face mask protect you from infection?
The CDC recommends that you wear a cloth face mask if you go out in public. This is an added layer of protection for everyone, on top of social distancing efforts. You can spread the virus when you talk or cough, even if you don’t know that you have it or if you aren’t showing signs of infection.
Surgical masks and N95 masks should be reserved for health care workers and first responders, the CDC says.
Is it safe to travel during a pandemic?
Crowded places can raise your chances of getting COVID-19. The CDC recommends against international or cruise ship travel during the pandemic.
A few questions may help you decide whether it’s safe to travel in the United States:
- Is the coronavirus spreading where you’re going?
- Will you have close contact with other people during the trip?
- Are you at higher risk of severe illness if you catch the virus?
- Do you live with someone who has a serious medical condition?
- Will the place where you’ll be staying be cleaned?
- Will you have access to food and other necessities?
If you choose to travel, stay away from sick people. Wash your hands often, and try not to touch your face. Wear a cloth face mask when you’ll be around other people. Some airlines require all customers to use them.
How can you help stop the spread of the coronavirus?
Some officials are easing restrictions and allowing businesses to reopen. This doesn’t mean the virus is gone. Continue to follow safety practices such as wearing a cloth face mask in public places.
Because the virus spreads from person to person, it’s important to limit your contact with other people as much as possible.
Some people work in “essential businesses” that are vital to daily life, such as health care, law enforcement, and public utilities. Everyone else should stay home as much as you can and wear a cloth face mask when you can’t. You might hear officials use these terms when they talk about staying home:
- Social distancing or physical distancing, keeping space between yourself and other people when you have to go out
- Quarantine, keeping someone home and separated from other people if they might have been exposed to the virus
- Isolation, keeping sick people away from healthy people, including using a separate “sick” bedroom and bathroom when possible
There’s no vaccine, but intense research to create one has been underway around the world since scientists shared the virus’s genetic makeup in January 2020. Vaccine testing in humans started with record speed in March 2020. More than 100 vaccine projects are in various phases of development.
There’s no specific treatment for COVID-19. People who get a mild case need care to ease their symptoms, like rest, fluids, and fever control. Take over-the-counter medicine for a sore throat, body aches, and fever. But don’t give aspirin to children or teens younger than 19.
You might have heard that you shouldn’t take ibuprofen to treat COVID-19 symptoms. But the National Institutes of Health says people who have the virus can use nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen a
Antibiotics won’t help because they treat bacteria, not viruses. If you hear about people with COVID-19 getting antibiotics, it’s for an infection that came along with the disease.
People with severe symptoms need to be cared for in the hospital.
Many clinical trials are under way to explore treatments used for other conditions that could fight COVID-19 and to develop new ones.
Several studies are focused on an antiviral medication called remdesivir, which was created to fight Ebola. An emergency FDA ruling lets doctors use it for people hospitalized with COVID-19 and in clinical trials. Researchers in the U.S. say remdesivir helped patients in one study recover from the disease 31% faster.
The FDA also issued an emergency use ruling for hydroxychloroquine and chloroquine. These medications are approved to treat malaria and autoimmune conditions like rheumatoid arthritis and lupus. Studies on their use against COVID-19 have had mixed results, and research is ongoing.
Clinical trials are also under way for tocilizumab, another medication used to treat autoimmune conditions. And the FDA is also allowing clinical trials and hospital use of blood plasma from people who’ve had COVID-19 and recovered to help others build immunity. You’ll hear this called convalescent plasma.
Is there a cure for the new coronavirus?
There’s no cure yet, but researchers are working hard to find one.
Every case is different. You may have mild flu-like symptoms for a few days after exposure, then get better. But some cases can be severe or fatal.
What is the recovery rate for coronavirus?
Scientists and researchers are constantly tracking COVID-19 infections and recoveries. But they don’t have information about the outcome of every infection. Early estimates predict that the overall COVID-19 recovery rate will be between 97% and 99.75%.
Doctors aren’t sure if you can get reinfected after you’ve had it. With other coronaviruses that only cause colds, you have a period that you’re immune, but that goes away over time.
Are coronaviruses new?
Coronaviruses were first identified in the 1960s. Almost everyone gets a coronavirus infection at least once in their life, most likely as a young child. In the United States, regular coronaviruses are more common in the fall and winter, but anyone can come down with a coronavirus infection at any time.
The symptoms of most coronaviruses are similar to any other upper respiratory infection, including a runny nose, coughing, sore throat, and sometimes a fever. In most cases, you won’t know whether you have a coronavirus or a different cold-causing virus, such as a rhinovirus. You treat this kind of coronavirus infection the same way you treat a cold.
Have there been other serious coronavirus outbreaks?
Coronaviruses have led to two serious outbreaks:
- Middle East respiratory syndrome (MERS). About 858 people have died from MERS, which first appeared in Saudi Arabia and then in other countries in the Middle East, Africa, Asia, and Europe. In April 2014, the first American was hospitalized for MERS in Indiana, and another case was reported in Florida. Both had just returned from Saudi Arabia. In May 2015, there was an outbreak of MERS in South Korea, which was the largest outbreak outside of the Arabian Peninsula.
- Severe acute respiratory syndrome (SARS). In 2003, 774 people died from an outbreak. As of 2015, there were no further reports of cases of SARS.
WebMD Medical Reference Reviewed by Michael W. Smith, MD on June 05, 2020
UpToDate: “Coronavirus disease 2019 (COVID-19): Management in adults,” “Coronavirus disease 2019 (COVID-19): Epidemiology, virology, clinical features, diagnosis, and prevention.”
TuftsNow: “How the Body Battles COVID-19.”
Thrombosis Research: “Incidence of thrombotic complications in critically ill ICU patients with COVID-19.”
European Centre for Disease Prevention and Control: “Disease background of COVID-19,” “Q&A on COVID-19.”
World Health Organization: “Coronavirus disease (COVID-19) advice for the public,” “Coronavirus Infections,” “Middle East respiratory syndrome coronavirus (MERS-CoV),” “Naming the coronavirus disease (COVID-19) and the virus that causes it,” “Novel Coronavirus(2019nCoV) Situation Report – 11,” “Novel Coronavirus(2019-nCoV) Situation Report – 22.” “Q&A on coronaviruses (COVID-19).” “Q&A: Similarities and differences – COVID-19 and influenza,” “Draft landscape of COVID-19 candidate vaccines – 20 April 2020,” “Tobacco and waterpipe use increases the risk of suffering from COVID-19.”
CDC: “2019 Novel Coronavirus (2019-nCoV), Wuhan, China,” “CDC Confirms Possible Instance of Community Spread of COVID-19 in U.S.,” “Coronavirus,” “Coronavirus Disease 2019 (COVID-19).”
The Lancet: “Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study.”
Elsevier: “Novel Coronavirus Information Center.”
University of California, San Francisco: “How the New Coronavirus Spreads and Progresses – And Why One Test May Not Be Enough.”
Harvard Health Publishing: “As coronavirus spreads, many questions and some answers,” “Coronavirus Resource Center.”
Cleveland Clinic: “Frequently Asked Questions about Coronavirus Disease 2019 (COVID-19).”
National Institutes of Health: “NIH clinical trial of investigational vaccine for COVID-19 begins,” “COVID-19 Treatment Guidelines.”
News release, National Institutes of Health.
Journal of Virology: “Middle East Respiratory Syndrome Coronavirus (MERS-CoV); Announcement of the Coronavirus Study Group.”
Journal of the American Medical Association News: “French Researchers: For Now, Middle Eastern Coronavirus Not Likely to Cause a Pandemic.”
Johns Hopkins Medicine: “Upper Respiratory Infection (URI) or Common Cold.”
Occupational Safety and Health Administration: “COVID-19.”
National Science Review: “On the origin and continuing evolution of SARS-CoV-2.”
World Health Organization: “Coronavirus disease (COVID-19) advice for the public: Myth busters,” “Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19).”
EClinical Medicine: “The coronavirus 2019-nCoV epidemic: Is hindsight 20/20?”
CDC: “CDC Confirms Possible Instance of Community Spread of COVID-19,” “Coronavirus Disease 2019 (COVID-19).”
The New England Journal of Medicine: “Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1,” “Large-Vessel Stroke as Presenting Feature of Covid-19 in the Young.”
American Stroke Association: “Stroke Symptoms.”
National Center for Complementary and Integrative Health: “In the News: Coronavirus and ‘Alternative’ Treatments.”
Yale School of Medicine: “The Ins and Outs of COVID-19 Testing. Who is being tested? What are tests looking for?
When might we have a vaccine?”
American Family Physician: “Aspirin Use in Children for Fever or Viral Syndromes.”
European Medicines Agency: “EMA gives advice on the use of non-steroidal anti-inflammatories for COVID-19.”
The BMJ: “Covid-19: ibuprofen should not be used for managing symptoms, say doctors and scientist.”
Medscape: “Coronavirus Disease 2019 (COVID-19) Treatment & Management,” “Sudden Loss of Taste and Smell Should Be Part of COVID-19 Screen.”
The Hospitalist: “CDC expert answers top COVID-19 questions.”
FDA: “Coronavirus (COVID-19) Update: Daily Roundup April 1, 2020,” “Emergency Use Authorization,” “Letter of Authorization: Dr. Rick Bright, Ph.D.,” “Understanding Unapproved Use of Approved Drugs ‘Off Label,’” “Coronavirus (COVID-19) Update: FDA Alerts Consumers About Unauthorized Fraudulent COVID-19 Test Kits,” “Coronavirus Disease 2019 (COVID-19) Frequently Asked Questions,” “Coronavirus (COVID-19) Update: Serological Tests.”
Nature Reviews: “The COVID-19 vaccine development landscape.”
National Academies Press: “Rapid Expert Consultation on SARS-CoV-2 Survival in Relation to Temperature and Humidity and Potential for Seasonality for the COVID-19 Pandemic.”
MedRxiv: “The Novel Coronavirus, 2019-nCoV, is Highly Contagious and More Infectious Than Initially Estimated.”
Pathogens: “SARS-CoV-2 and Coronavirus Disease 2019: What We Know So Far.”
Hartford HealthCare: “How to Avoid COVID-19 at the Supermarket.”
Commonwealth of Massachusetts: “COVID-19 Essential Services FAQs.”
Emerging Infectious Diseases: “Case-Fatality Risk Estimates for COVID-19 Calculated by Using a Lag Time for Fatality.”
Johns Hopkins Bloomberg School of Public Health Center for Health Security: “Serology-based tests for COVID-19.”
Mayo Clinic: “COVID-19 (coronavirus) vaccine: Get the facts.”
American Society of Clinical Oncology: “Common Questions About COVID-19 and Cancer: Answers for Patients and Survivors.”
News release, Abbott.
News release, AstraZeneca.
Delta News Hub: “Delta expands safety commitment by requiring all customers to wear face coverings across travel.”
News release, FDA.
Intermountain Healthcare: “What’s the difference between a cold, the flu, seasonal allergies and coronavirus?”
Boston Children’s Hospital: “COVID-19 and a serious inflammatory syndrome in children: Unpacking recent warnings.”
KidsHealth/Nemours: “Kawasaki Disease.”
World Organisation for Animal Health: “Questions and Answers on the COVID-19.”
© 2020 WebMD, LLC. All rights reserved.