Archived: Coronavirus (COVID-19) Overview

Editor's note: For the latest updates on the 2023 coronavirus outbreak, see our news coverage.

COVID-19 is a disease caused by SARS-CoV-2 that can trigger what doctors call a respiratory tract infection. In early 2020,  the World Health Organization identified SARS-CoV-2 as a new type of coronavirus. The outbreak quickly spread around the world.  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 to otherwise healthy people.

Is there more than one strain of SARS-CoV-2?

Yes, the COVID-19 virus continues to mutate and there are several variants that are now spreading. Some are more contagious as well as more deadly than the original virus. 

Throughout the pandemic, scientists have kept a close eye on variants like:

• Alpha
• Beta
• Gamma
• Delta
• Epsilon
• Eta
• Iota
• Kappa
• Omicron
• N/A
• Mu
• Zeta

How long will the coronavirus last?

There's no way to tell how long the pandemic will continue. There are many factors, including the public's efforts to slow the spread, researchers' work to learn more about the virus, their search for a treatment, and the success of the vaccines.

The main symptoms include:

• Fever 
• Coughing
• Shortness of breath
• Trouble breathing
• Fatigue
• Chills, sometimes with shaking
• Body aches
• Headache
• Sore throat
• Congestion/runny nose
• Loss of smell or taste
• Nausea
• Diarrhea

The virus can lead to pneumonia, respiratory failure, heart problems, liver problems, 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. In some cases, lung transplants have been needed.

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
• 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%

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 have been exposed to people who have it within the last 14 days.

Researchers aren't sure what caused it, and investigations as to its origin are ongoing. 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.

Anyone can get COVID-19, and most infections are mild. The older you are, the higher your risk of severe illness.

You also a have higher chance of serious illness if you have one of these health conditions:

• Chronic kidney disease
• Chronic obstructive pulmonary disease (COPD)
• A weakened immune system because of an organ transplant
• Obesity
• Serious heart conditions such as heart failure or coronary artery disease
• Sickle cell disease
• Type 2 diabetes

Conditions that could lead to severe COVID-19 illness include:

• Moderate to severe asthma
• Diseases that affect your blood vessels and blood flow to your brain
• Cystic fibrosis
• High blood pressure
• A weakened immune system because of a blood or bone marrow transplant, HIV, or medications like corticosteroids
• Dementia
• Liver disease
• Pregnancy
• Damaged or scarred lung tissue (pulmonary fibrosis)
• Smoking
• Thalassemia
• Type 1 diabetes
• Depression
• Anxiety
• Schizophrenia

Some children and teens who are in the hospital with COVID-19 have an inflammatory condition that doctors are calling multisystem inflammatory syndrome in children. 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.

If you have preexisting mood disorders, you may be at high risk for hospitalization or death but not necessarily severe COVID-19.

That said, having schizophrenia is the biggest risk factor for besides age for COVID mortality. Those with schizophrenia spectrum disorders are prone to metabolic syndrome, which includes increased blood pressure, high blood sugar, and is associated with systemic inflammation. All of which is exacerbated by COVID.

Mood and anxiety disorders were not connected to the higher risk, but people living with mental health conditions may have certain symptoms that can interfere with their ability to care for themselves and be engaged in their health decisions. This can make it hard to effectively follow health behaviors like maintaining social distancing or staying in quarantine to reduce the spread of the infection.

Moreover, people with mental health and mood disorders are also more likely to have conditions like diabetes and heart problems which are major risk factors for severe COVID-19.

There are also several socio-economic reasons why preexisting mood disorders can increase your chances of hospitalization and death if you get COVID-19.
This includes:

• Poverty
• Lack of access to preventative health care
• Ability to understand health recommendations
• Lack of access to affordable health care
• Living in tight spaces or facilities like nursing homes, homeless shelters, prisons, or psychiatric inpatient units

How does COVID-19 spread?

COVID-19 mainly spreads from person to person. People release respiratory fluids during exhalation (e.g., quiet breathing, speaking, singing, exercise, coughing, sneezing) in the form of droplets across a spectrum of sizes. These droplets carry viruses and transmit infection. The largest droplets settle out of the air rapidly, within seconds to minutes. The smallest very fine droplets, and aerosol particles formed when these fine droplets rapidly dry, are small enough that they can remain suspended in the air for minutes to hours.

The risk of transmission is greatest within three to six feet of an infectious source where the concentration of these very fine droplets and particles is greatest. 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.

While less likely, 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. OVID-19 can last for several hours on various types of surfaces:

• Copper (pennies, teakettles, cookware): 4 hours
• Cardboard (shipping boxes): up to 24 hours
• Plastic (milk containers, detergent bottles, subway and bus seats, elevator buttons):2 to 3 days
• Stainless steel (refrigerators, pots and pans, sinks, some water bottles): 2 to 3 days

That's why it's important to wash or sanitize your hands regularly and 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. There's no evidence that humans can catch this coronavirus from an animal, but it appears it can be passed from humans to animals.

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 exposed to someone 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. This type of occurrence has been happening with the variants as well.

How fast is it spreading?

The number of people infected or re-infected by COVID-19 changes every day. See our news story for the latest updates on this developing story.

Call your doctor or local health department if you think you've been exposed and have symptoms like:

• Fever of 100 F or higher
• Cough
• Trouble breathing

Home testing has advanced considerably since the beginning of the pandemic and you can readily test yourself. 
Otherwise, testing facilities are readily available in most areas. While some require an appointment, others are simply drive-up. Home testing kits are also widely available.

A swab test is the most common testing method. It looks for signs of the virus in your upper respiratory tract. You or 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.

Getting vaccinated against COVID-19 is a key part of prevention. But you should also take these steps:

• 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 mask 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 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
• Wash your hands often with soap and water or clean them with an alcohol-based sanitizer. This kills viruses on your hands.
• 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.
• 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.
• 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.

Can a face mask protect you from infection?

A mask is an added layer of protection for everyone, on top of vaccines and 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.

It's important to wear a high-quality mask in a variety of situations:

Wear a mask indoors in public places if you're in an area where there's a high or “substantial” amount of COVID spreading around. That goes for people 2 years old and up. 

If you have a chronic health condition or you're taking meds that weaken your immune system, wear a mask in indoor public places even if you're fully vaccinated. Do this unless your doctor tells you otherwise. In general, you don't need to wear a mask outside, where it's harder for the coronavirus to spread. But if COVID-19 cases are high in your area, consider wearing one in crowded outdoor places and for outdoor get-togethers that involve close contact with people who aren't fully vaccinated.

N95 respirator masks fit tightly around your face and filter out 95% or more of the smallest particles in the air. 

It's fine to buy a basic, disposable N95 respirator. Choose one that's high quality and says “NIOSH Approved” on the label.

Is it safe to travel during a pandemic?

Crowded places can raise your chances of getting COVID-19. It’s important to check the status of COVID-19 transmissions in the area where you travel before you go and take the necessary precautions while there.

A few questions may help you decide whether it's safe to travel:

• 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 high-quality cloth face mask when you are around other people. 

The CDC recommends that everyone 6 months and older be vaccinated. There are four vaccines, which have been granted FDA approval; Pfizer BioNTech, Moderna, Novavax, and Johnson & Johnson. 

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 as usual.

Antibiotics won't help because they treat bacteria, not viruses. In January 2022, the FDA limited the use of two monoclonal treatments that previously were used to treat COVID-19 infections after it was found that they were not effective against the Omicron variant. These two monoclonal antibody treatments are bamlanivimab and etesevimab (administered together) and REGEN-COV (casirivimab and imdevimab).Sotrovimab is the only available monoclonal treatment with activity against the Omicron variant. 

Many clinical trials are underway to explore treatments used for other conditions that could fight COVID-19 and to develop new ones.

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.

Symptoms can also linger for weeks, even if they're mild.

More than a third of people older than 18 who have signs of the virus aren't totally recovered 2 or 3 weeks later, according to a CDC survey. Fatigue and cough were the symptoms that were most likely to linger.

Some other people who've had COVID-19 develop a condition similar to myalgic encephalomyelitis, also known as chronic fatigue syndrome. They may have brain fog, severe fatigue, pain, trouble thinking, or dizziness.

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%.

Can you get the coronavirus multiple times?

Yes. This is another reason to stay vigilant against becoming infected and transmitting the virus. 

As with other coronaviruses that only cause colds, you have a period that you're immune, but that goes away over time. That also appears to be the case with this coronavirus. Immunity is estimated to last up to three months.

Having COVID-19 usually results in antibodies which should help protect you from re-infection. But the virus continues to mutate and these changes can lead to new variants which allow the risk for re-infection.

The CDC is investigating how often reinfections occur, who is at higher risk of reinfection, how soon reinfections take place after a previous infection, and the severity of reinfections compared with initial infections.
 

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.