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Patient education: COVID-19 overview (The Basics)

Patient education: COVID-19 overview (The Basics)

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What is COVID-19? — COVID-19 stands for "coronavirus disease 2019." It is caused by a virus called SARS-CoV-2. The virus first appeared in late 2019 and quickly spread around the world.

What are the symptoms of COVID-19? — Symptoms usually start 4 or 5 days after a person is infected with the virus. But in some people, it can take up to 2 weeks for symptoms to appear. Some people never show symptoms at all.

When symptoms do happen, they can include:



Trouble breathing

Feeling tired

Shaking chills

Muscle aches


Sore throat

Runny or stuffy nose

Problems with sense of smell or taste

Some people have digestive problems like nausea or diarrhea. There have also been some reports of rashes or other skin symptoms. For example, some people with COVID-19 get reddish-purple spots on their fingers or toes. But it's not clear why or how often this happens.

For most people, symptoms will get better within a few days to weeks. But a small number of people get very sick and stop being able to breathe on their own. In severe cases, their organs stop working, which can lead to death.

Some people with COVID-19 continue to have some symptoms for weeks or months. This seems to be more likely in people who are sick enough to need to stay in the hospital. But this can also happen in people who did not get very sick. Doctors are still learning about the long-term effects of COVID-19.

While children can get COVID-19, they are less likely than adults to have severe symptoms. More information about COVID-19 and children is available separately. (See "Patient education: COVID-19 and children (The Basics)".)

Am I at risk for getting seriously ill? — It depends on your age and health. In some people, COVID-19 leads to serious problems like pneumonia, not getting enough oxygen, heart problems, or even death. This risk gets higher as people get older. It is also higher in people who have other health problems like serious heart disease, chronic kidney disease, type 2 diabetes, chronic obstructive pulmonary disease (COPD), sickle cell disease, or obesity. People who have a weak immune system for other reasons (for example, HIV infection or certain medicines), asthma, cystic fibrosis, type 1 diabetes, or high blood pressure might also be at higher risk for serious problems.

How is COVID-19 spread? — The virus that causes COVID-19 mainly spreads from person to person. This usually happens when an infected person coughs, sneezes, or talks near other people. The virus is passed through tiny particles from the infected person's lungs and airway. These particles can easily travel through the air to other people who are nearby. In some cases, like in indoor spaces where the same air keeps being blown around, virus in the particles might be able to spread to other people who are farther away.

The virus can be passed easily between people who live together. But it can also spread at gatherings where people are talking close together, shaking hands, hugging, sharing food, or even singing together. Eating at restaurants raises the risk of infection, since people tend to be close to each other and not covering their faces. Doctors also think it is possible to get infected if you touch a surface that has the virus on it and then touch your mouth, nose, or eyes. However, this is probably not very common.

A person can be infected, and spread the virus to others, even without having any symptoms.

Are there different variants of the virus that causes COVID-19? — Yes. Viruses constantly change or "mutate." When this happens, a new strain or "variant" can form. Most of the time, new variants do not change the way a virus works. But when a variant has changes in important parts of the virus, it can act differently.

Experts have discovered several new variants of the virus that causes COVID-19. Some variants seem to spread more easily than the original virus. Certain variants might also make people sicker than others.

Experts are studying the different variants. This will help them better understand how far they have spread, whether they affect people differently, and how well different vaccines protect against them.

The more people who get vaccinated against COVID-19, the harder it will be for the virus to form new variants.

Is there a test for the virus that causes COVID-19? — Yes. If your doctor or nurse suspects you have COVID-19, they might take a swab from inside your nose or mouth for testing. In some cases, they might take a sample of your saliva. These tests can help your doctor figure out if you have COVID-19 or another illness.

There are 2 types of tests used to diagnose COVID-19:

Molecular tests – These look for the genetic material from the virus. They are also called "nucleic acid tests." You can get a molecular test at a doctor's office, clinic, or pharmacy. There are also places that make these tests available for lots of people, often at drive-through locations. Depending on the lab, it can take up to several days to get test results back.

Molecular tests are the best way to know if a person has COVID-19. That's because they can detect even very low levels of virus in the body.

Antigen tests – These look for proteins from the virus. They can give results faster than most molecular tests. You can do an antigen test at a doctor's office, clinic, pharmacy, or through some organizations that make testing available in other places. You can also buy antigen tests to use at home.

Antigen tests are not as accurate as molecular tests. They are more likely to give "false negative" results. This is when the test comes back negative even though the person actually is infected. But antigen tests can still be useful in some situations, when results are needed quickly or a molecular test is not available. For example, if a person has early symptoms of COVID-19, an antigen test can be accurate enough to detect virus in their body. If a person gets an antigen test and the result is negative, a molecular test might be needed to confirm they do not have the virus in their body. This might be done if the person has symptoms or knows they were exposed the virus.

There is also a blood test that can show if a person has had COVID-19 in the past. This is called an "antibody" test. Antibody tests are generally not used on their own to diagnose COVID-19 or make decisions about care. But experts can use them to learn how many people in a certain area were infected without knowing it.

Can COVID-19 be prevented? — The best way to prevent COVID-19 is to get vaccinated. In the US, people age 5 and older can get a vaccine. People age 12 and older should also get a "booster" shot to give them extra protection. People who are fully vaccinated are at much lower risk of getting sick from the virus.

More information about COVID-19 vaccines and boosters is available separately. (See "Patient education: COVID-19 vaccines (The Basics)".)

In addition to vaccination, there are other things you can do to help protect yourself and others. These include:

Face masks – Wearing a mask is most important when you need to be in public around other people. Make sure your mask covers your mouth and nose.

You can buy cloth masks and disposable masks in stores or online. Cloth masks work best if they have several layers of fabric. Some people prefer to use "respirator" masks that can filter out even very tiny air particles. These include "N95" and "KN95" masks. They give more protection than fabric or disposable masks. These might be a better choice for people who have a weak immune system or other health conditions. Whatever type of mask you use, it's important that it fits snugly over your face with no gaps. You can improve the fit by using a mask with an adjustable nose wire, adjusting or knotting the ear loops to make it tighter, or wearing a cloth mask on top of a disposable mask.

Social distancing – It's most important to avoid contact with people who are sick. But "social distancing" also means staying at least 6 feet (about 2 meters) from anyone outside your household. That's because the virus can spread easily through close contact, and it's not always possible to know who is infected.

Hand washing – Wash your hands with soap and water often. This also helps protect you from other illnesses, like the flu or the common cold. Try to avoid touching your face if you have not washed your hands.

Make sure to rub your hands with soap for at least 20 seconds, cleaning your wrists, fingernails, and in between your fingers. Then rinse your hands and dry them with a paper towel you can throw away. If you are not near a sink, you can use a hand sanitizing gel to clean your hands. The gels with at least 60 percent alcohol work the best.

Staying safe when traveling – Any form of travel, especially if you spend time in crowded places like airports, increases your risk of getting and spreading infection.

Be sure to check what the rules are in the area you are visiting. For example, depending on the situation, you might need to have a negative COVID-19 test, show proof of vaccination, or "self-quarantine" for some length of time after traveling. Information about traveling to or from the US is available online at

When can I stop wearing a mask? — This depends on what the rules are in your area. In general, experts recommend continuing to take the steps above if you are in an area where the COVID-19 "community level" is high. In the US, you can check the level in your area here: It's also a good idea to take extra steps to protect yourself if you are at high risk for severe illness.

In places where the COVID-19 level is not high, many people wonder when it's safe to stop doing these things. The answer to this depends on:

Your health and how likely you are to get very sick if you do get COVID-19

Whether you live with people who are at high risk for serious illness

How comfortable you are taking some amount of risk

The answers to these questions will be different for everyone. Some people choose to continue to wear a mask in public or in large groups. Other people are comfortable doing some activities without a mask. Different activities have different levels of risk.

In the US, masks are required on airplanes, trains, buses, and other forms of public transportation. Businesses and events might have their own rules about masks, too.

You should continue to wear a mask around other people if you:

Have symptoms that could be caused by COVID-19

Have recently tested positive for the virus

Have recently been exposed to COVID-19

What should I do if I have symptoms? — If you have a fever, cough, trouble breathing, or other symptoms of COVID-19, call your doctor or nurse. They will ask about your symptoms. They might also ask about any recent travel and whether you have been around anyone who might have been infected. Then they can tell you if you should come in or go somewhere else to be tested.

If your symptoms are not severe, it is best to call before you go in. The staff can tell you what to do and whether you need to be seen in person. Many people with only mild symptoms should stay home and avoid other people until they get better. If you do need to go to the clinic or hospital, be sure to wear a mask. This helps protect other people. The staff might also have you wait someplace away from other people.

If you are severely ill and need to go to the clinic or hospital right away, you should still call ahead if possible. This way the staff can care for you while taking steps to protect others. If you think you are having a medical emergency, call for an ambulance (in the US and Canada, call 9-1-1).

What if I feel fine but think I was exposed? — If you think you were in close contact with someone with COVID-19, what to do next depends on whether you are vaccinated. It also depends on how long ago you got the vaccine and whether you have had a booster shot. Although people who are fully vaccinated are less likely to get sick and infect others, it can still happen. This is why it's important to take steps to lower this risk.

First, think about these questions:

Have you gotten a booster shot?

Have you had 2 doses of the Pfizer or Moderna vaccine within the last 6 months?

Have you had the Johnson and Johnson vaccine within the last 2 months?

If you answered "yes" to any of the above questions, experts recommend doing the following after being exposed to someone with COVID-19:

You do not need to self-quarantine. But you should wear a mask around all other people for 10 days.

If possible, get tested 5 days after the exposure:

If your test is negative, continue to wear a mask around other people until 10 total days have passed

If your test is positive, stay home and "self-isolate" for at least 5 days

If you start to have symptoms at any point, stay home and get tested again

If you have not been vaccinated at all, or if you answered "no" to all of the above questions, experts recommend doing the following:

Self-quarantine for 5 days after the exposure. This means staying home and away from other people as much as possible. If you need to be around people, like in your home, wear a mask.

If possible, get tested 5 days after the exposure:

If your test is negative, continue to wear a mask around other people until 10 total days have passed

If your test is positive, continue to stay home and "self-isolate" for at least another 5 days

If you start to have symptoms at any point, stay home and get tested again

The guidance around what to do after being exposed has changed over time. That's because experts have learned more about the virus and when a person is most likely to infect others. If you are not sure whether you need to self-quarantine, or when you can go back to your normal activities, ask your doctor or nurse.

How is COVID-19 treated? — Many people will be able to stay home while they get better. But people with serious symptoms or other health problems might need to go to the hospital.

Mild illness – Mild illness means you might have symptoms like fever and cough, but you do not have trouble breathing. Most people with COVID-19 have mild illness and can rest at home until they get better. This usually takes about 2 weeks, but it's not the same for everyone.

If you are recovering from COVID-19, it's important to stay home and "self-isolate" while you are most likely to spread the virus. Self-isolation means staying apart from other people, even the people you live with. When you can stop self-isolation will depend on how long it has been since you had symptoms, and in some cases, whether you have had a negative test (showing that the virus is no longer in your body). If you are generally healthy and your symptoms are improving (or you don't have symptoms), experts recommend self-isolating for at least 5 days. The 5 days starts the day after you develop symptoms or get tested. After this, you should wear a mask around all other people for 5 more days.

If you are not sure how long to self-isolate, or if you still have symptoms after 5 days, talk to your doctor or nurse. You should also check with your doctor or nurse if you have a weakened immune system.

If you are at risk for getting seriously ill, doctors might recommend treatment even if you only have mild symptoms. This can lower your risk of getting sicker. Options might include pills that you take for a few days, a treatment called "monoclonal antibodies" that is given through an IV or as a shot, and another medicine that is given by IV. Doctors also might recommend being part of a clinical trial. This is a scientific study that tests new medicines to see how well they work. Do not try any new medicines or treatments without talking to a doctor.

Severe illness – If you have more severe illness with trouble breathing, you might need to stay in the hospital, possibly in the intensive care unit (also called the "ICU"). While you are there, you will most likely be in a special isolation room. Only medical staff will be allowed in the room, and they will have to wear special gowns, gloves, masks, and eye protection.

The doctors and nurses can monitor and support your breathing and other body functions and make you as comfortable as possible. You might need extra oxygen to help you breathe easily. If you are having a very hard time breathing, you might need a breathing tube. The tube goes down your throat and into your lungs. It is connected to a machine to help you breathe, called a "ventilator." You might also get medicines that have been shown to help some people with severe COVID-19.

What should I do if someone in my home has COVID-19? — If someone in your home has COVID-19, there are additional things you can do to protect yourself and others:

Keep the sick person away from others – The sick person should stay in a separate room, and use a different bathroom if possible. They should also eat in their own room.

Experts also recommend that the person stay away from pets in the house until they are better.

Have them wear a mask – The sick person should wear a mask when they are in the same room as other people. If they can't wear a mask, you can help protect yourself by covering your face when you are in the room with them.

Wash hands – Wash your hands with soap and water often.

Clean often – Here are some specific things that can help:

Wear disposable gloves when you clean. It's also a good idea to wear gloves when you have to touch the sick person's laundry, dishes, utensils, or trash. Wash your hands after removing your gloves.

Regularly clean things that are touched a lot. This includes counters, bedside tables, doorknobs, computers, phones, and bathroom surfaces.

Clean things in your home with soap and water, but also use disinfectants on appropriate surfaces. Some cleaning products work well to kill bacteria, but not viruses, so it's important to check labels. The US Environmental Protection Agency (EPA) has a list of products here:

What if I am pregnant? — More information about COVID-19 and pregnancy is available separately. (See "Patient education: COVID-19 and pregnancy (The Basics)".)

If you are pregnant and you have questions about COVID-19, talk to your doctor, nurse, or midwife. They can help.

What can I do to cope with stress and anxiety? — It's normal to feel anxious or worried about COVID-19. It's also normal to feel stressed, lonely, or tired of not being able to do your usual activities. You can take care of yourself by trying to:

Take breaks from the news

Get regular exercise and eat healthy foods

Find activities that you enjoy and can do at home

Stay in touch with your friends and family members

It might help to remember that by doing things like getting vaccinated and following local guidelines, you are helping to protect other people in your community.

Where can I go to learn more? — As we learn more about this virus, expert recommendations will continue to change. Check with your doctor or public health official to get the most updated information about how to protect yourself and others.

For information about COVID-19 in your area, you can call your local public health office. In the US, this usually means your city or town's Board of Health. Many states also have a "hotline" phone number you can call.

You can find more information about COVID-19 at the following websites:

US Centers for Disease Control and Prevention (CDC):

World Health Organization (WHO):

More on this topic

Patient education: COVID-19 vaccines (The Basics)
Patient education: COVID-19 and children (The Basics)
Patient education: COVID-19 and pregnancy (The Basics)
Patient education: Recovery after COVID-19 (The Basics)
Patient education: Pneumonia in adults (The Basics)
Patient education: What are clinical trials? (The Basics)

This topic retrieved from UpToDate on: Mar 03, 2022.
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