If you've been exposed to the coronavirus

If you've been exposed, are sick, or are caring for someone with COVID-19

Published: March, 2020

As the new coronavirus spreads across the globe, the chances that you will be exposed and get sick continue to increase. If you've been exposed to someone with COVID-19 or begin to experience symptoms of the disease, you may be asked to self-quarantine or self-isolate. What does that entail, and what can you do to prepare yourself for an extended stay at home? How soon after you're infected will you start to be contagious? And what can you do to prevent others in your household from getting sick?

What are the symptoms of COVID-19?

Some people infected with the virus have no symptoms. When the virus does cause symptoms, common ones include fever, body ache, dry cough, fatigue, chills, headache, sore throat, loss of appetite, and loss of smell. In some people, COVID-19 causes more severe symptoms like high fever, severe cough, and shortness of breath, which often indicates pneumonia.

People with COVID-19 are also experiencing neurological symptoms, gastrointestinal (GI) symptoms, or both. These may occur with or without respiratory symptoms.

For example, COVID-19 affects brain function in some people. Specific neurological symptoms seen in people with COVID-19 include loss of smell, inability to taste, muscle weakness, tingling or numbness in the hands and feet, dizziness, confusion, delirium, seizures, and stroke.

In addition, some people have gastrointestinal (GI) symptoms, such as loss of appetite, nausea, vomiting, diarrhea, and abdominal pain or discomfort associated with COVID-19. These symptoms might start before other symptoms such as fever, body ache, and cough. The virus that causes COVID-19 has also been detected in stool, which reinforces the importance of hand washing after every visit to the bathroom and regularly disinfecting bathroom fixtures.

What should I do if I think I or my child may have a COVID-19 infection?

First call your doctor or pediatrician for advice.

If you do not have a doctor and you are concerned that you or your child may have COVID-19, contact your local board of health. They can direct you to the best place for evaluation and treatment in your area.

It's best to not seek medical care in an emergency department unless you have symptoms of severe illness. Severe symptoms include high or very low body temperature, shortness of breath, confusion, or feeling you might pass out. Call the emergency department ahead of time to let the staff know that you are coming, so they can be prepared for your arrival.

How do I know if I have COVID-19 or the regular flu?

COVID-19 often causes symptoms similar to those a person with a bad cold or the flu would experience. And like the flu, the symptoms can progress and become life-threatening. Your doctor is more likely to suspect coronavirus if:

  • you have respiratory symptoms
  • and
  • you have been exposed to someone suspected of having COVID-19, or
  • there has been community spread of the virus that causes COVID-19 in your area.

How is someone tested for COVID-19?

A specialized diagnostic test must be done to confirm that a person has an active coronavirus infection. Most often a clinician takes a swab of your nose (or both your nose and throat). Some tests may be done using a saliva sample. The sample is then checked for the virus's genetic material (PCR test) or for specific viral proteins (antigen test).

Antibody tests can tell if someone has been infected with COVID-19. But the infected person doesn't begin producing antibodies immediately. It can take as long as three weeks for a blood antibody test to turn positive. That's why it is not useful as a diagnostic test for someone with new symptoms.

What is the difference between a PCR test and an antigen test for COVID-19?

PCR tests and antigen tests are both diagnostic tests, which means that they can be used to determine whether you currently have an active coronavirus infection. However, there are important differences between these two types of tests.

PCR tests detect the presence of the virus's genetic material using a technique called reverse transcriptase polymerase chain reaction, or RT-PCR. For this test, a sample may be collected through a nasal or throat swab, or a saliva sample may be used. The sample is typically sent to a laboratory where coronavirus RNA (if present) is extracted from the sample and converted into DNA. The DNA is then amplified, meaning that many of copies of the viral DNA are made, in order to produce a measurable result. The accuracy of any diagnostic test depends on many factors, including whether the sample was collected properly, when during the course of illness the testing was done, and whether the sample was maintained in appropriate conditions while it was shipped to the laboratory. Generally speaking, PCR tests are highly accurate. However, it can take days to over a week to get the results of a PCR test.

Antigen tests detect specific proteins on the surface of the coronavirus. They are sometimes referred to as rapid diagnostic tests because it can take less than an hour to get the test results. Positive antigen test results are highly specific, meaning that if you test positive you are very likely to be infected. However, there is a higher chance of false negatives with antigen tests, which means that a negative result cannot definitively rule out an active infection. If you have a negative result on an antigen test, your doctor may order a PCR test to confirm the result.

It may be helpful to think of a COVID antigen test as you would think of a rapid strep test or a rapid flu test. A positive result for any of these tests is likely to be accurate, and allows diagnosis and treatment to begin quickly, while a negative result often results in further testing to confirm or overturn the initial result.

What are the differences between the nasal swab and saliva tests for COVID-19?

Samples for COVID-19 tests may be collected through a long swab that is inserted into the nose and sometimes down to the throat, or from a saliva sample.

The saliva test is easier to perform — spitting into a cup versus submitting to a swab — and more comfortable. Because a person can independently spit into a cup, the saliva test does not require interaction with a healthcare worker. This cuts down on the need for masks, gowns, gloves, and other protective equipment, which has been in short supply.

Either saliva or swab samples may be used for PCR tests, which detect genetic material from the coronavirus. Swab samples can also be used for antigen tests, which detect specific proteins on the surface of the coronavirus.

How reliable is the test for COVID-19?

Two types of diagnostic tests are currently available in the US. PCR tests detect viral RNA. Antigen tests, also called rapid diagnostic tests, detect specific proteins on the surface of the coronavirus. Antigen test results may come back in as little as 15 to 45 minutes; you may wait several days or longer for PCR test results.

The accuracy of any diagnostic test depends on many factors, including whether the sample was collected properly. For PCR tests, which are typically analyzed in a laboratory, test results may be affected by the conditions in which the test was shipped to the laboratory.

Results may also be affected by the timing of the test. For example, if you are tested on the day you were infected, your test result is almost guaranteed to come back negative, because there are not yet enough viral particles in your nose or saliva to detect. The chance of getting a false negative test result decreases if you are tested a few days after you were infected, or a few days after you develop symptoms.

Generally speaking, if a test result comes back positive, it is almost certain that the person is infected.

A negative test result is less definite. There is a higher chance of false negatives with antigen tests. If you have a negative result on an antigen test, your doctor may order a PCR test to confirm the result.

If you experience COVID-like symptoms and get a negative PCR test result, there is no reason to repeat the test unless your symptoms get worse. If your symptoms do worsen, call your doctor or local or state healthcare department for guidance on further testing. You should also self-isolate at home. Wear a mask when interacting with members of your household. And practice physical distancing.

I've heard that the immune system produces different types of antibodies when a person is infected with the COVID-19 coronavirus. How do they differ? Why is this important?

When a person gets a viral or bacterial infection, a healthy immune system makes antibodies against one or more components of the virus or bacterium.

The COVID-19 coronavirus contains ribonucleic acid (RNA) surrounded by a protective layer, which has spike proteins on the outer surface that can latch on to certain human cells. Once inside the cells, the viral RNA starts to replicate and also turns on the production of proteins, both of which allow the virus to infect more cells and spread throughout the body, especially to the lungs.

While the immune system could potentially respond to different parts of the virus, it's the spike proteins that get the most attention. Immune cells recognize the spike proteins as a foreign substance and begin producing antibodies in response.

There are two main categories of antibodies:

Binding antibodies. These antibodies can bind to either the spike protein or a different protein known as the nucleocapsid protein. Binding antibodies can be detected with blood tests starting about one week after the initial infection. If antibodies are found, it's extremely likely that the person has been infected with the COVID-19 coronavirus. The antibody level declines over time after an infection, sometimes to an undetectable level.

Binding antibodies help fight the infection, but they might not offer protection against getting reinfected in the future. It depends on whether they are also neutralizing antibodies.

Neutralizing antibodies. The body makes these antibodies specifically against the spike protein. In the laboratory, scientists have observed that neutralizing antibodies block the virus from getting into live cells. The FDA has not yet authorized use of a test for neutralizing antibodies, because it requires handling live COVID-19 coronavirus or a pseudo-virus similar to the real thing. To do the test, a person's blood is mixed with live virus and incubated in a test tube along with living cells to measure the killing action.

In addition to these laboratory observations, human studies have shown that neutralizing antibodies made against other coronaviruses help prevent re-infection.

Scientists are optimistic that the same will be true for the COVID-19 coronavirus, and that neutralizing antibodies will block cell-to-cell transmission of this virus in humans, and offer protection against reinfection, at least for two to three months.

Also, people who have completely recovered from a COVID-19 infection and have neutralizing antibodies in their blood can potentially donate plasma, the component of blood that contains antibodies, to help COVID-19 patients recover from their illness.

Do the antibodies produced by a person who has been infected with coronavirus protect them from becoming infected again?

Most people who are infected with the COVID-19 virus, whether or not they have symptoms, produce antibodies (proteins that fight infections). New research published in Nature Medicine looked at how long those antibodies last. Results from this small study suggest that levels of one type of antibody dropped sharply within two to three months. However, the decrease in neutralizing antibodies, which target the spike protein on the coronavirus and can help protect against reinfection, was much smaller.

Whether or not the remaining antibodies protect against reinfection, and for how long, is still unclear. It's possible that even low levels of neutralizing antibodies may be able to protect against reinfection. On the other hand, the presence of antibodies does not guarantee immunity.

Another consideration is that antibodies are only one part of the body's immune response. Memory B cells, for example, can quickly generate a strong antibody response to a virus the body has encountered before.

What is serologic (antibody) testing for COVID-19? What can it be used for?

A serologic test is a blood test that looks for antibodies created by your immune system. There are many reasons you might make antibodies, the most important of which is to help fight infections. The serologic test for COVID-19 specifically looks for antibodies against the COVID-19 virus.

Your body takes at least five to 10 days after you have acquired the infection to develop antibodies to this virus. For this reason, serologic tests are not sensitive enough to accurately diagnose an active COVID-19 infection, even in people with symptoms.

However, serologic tests can help identify anyone who has recovered from coronavirus. This may include people who were not initially identified as having COVID-19 because they had no symptoms, had mild symptoms, chose not to get tested, had a false-negative test, or could not get tested for any reason. Serologic tests will provide a more accurate picture of how many people have been infected with, and recovered from, coronavirus, as well as the true fatality rate.

Serologic tests may also provide information about whether people become immune to coronavirus once they've recovered and, if so, how long that immunity lasts. In time, these tests may be used to determine who can safely go back out into the community.

Scientists can also study coronavirus antibodies to learn which parts of the coronavirus the immune system responds to, in turn giving them clues about which part of the virus to target in vaccines they are developing.

Serological tests are starting to become available and are being developed by many private companies worldwide. However, the accuracy of these tests needs to be validated before widespread use in the US.

How soon after I'm infected with the new coronavirus will I start to be contagious?

The time from exposure to symptom onset (known as the incubation period) is thought to be three to 14 days, though symptoms typically appear within four or five days after exposure.

We know that a person with COVID-19 may be contagious 48 to 72 hours before starting to experience symptoms. Emerging research suggests that people may actually be most likely to spread the virus to others during the 48 hours before they start to experience symptoms.

If true, this strengthens the case for face masks, physical distancing, and contact tracing, all of which can help reduce the risk that someone who is infected but not yet contagious may unknowingly infect others.

For how long after I am infected will I continue to be contagious? At what point in my illness will I be most contagious?

People are thought to be most contagious early in the course of their illness, when they are beginning to experience symptoms, especially if they are coughing and sneezing. But people with no symptoms can also spread the coronavirus to other people if they stand too close to them. In fact, people who are infected may be more likely to spread the illness if they are asymptomatic, or in the days before they develop symptoms, because they are less likely to be isolating or adopting behaviors designed to prevent spread.

Most people with coronavirus who have symptoms will no longer be contagious by 10 days after symptoms resolve. People who test positive for the virus but never develop symptoms over the following 10 days after testing are probably no longer contagious, but again there are documented exceptions. So some experts are still recommending 14 days of isolation.

One of the main problems with general rules regarding contagion and transmission of this coronavirus is the marked differences in how it behaves in different individuals. That's why everyone needs to wear a mask and keep a physical distance of at least six feet.

Here is a more "scientific" way to determine if you are no longer contagious: have two nasal-throat tests or saliva tests 24 hours apart that are both negative for the virus.

If I get sick with COVID-19, how long until I will feel better?

It depends on how sick you get. Most people with mild cases appear to recover within one to two weeks. However, recent surveys conducted by the CDC found that recovery may take longer than previously thought, even for adults with milder cases who do not require hospitalization. The CDC survey found that one-third of these adults had not returned to normal health within two to three weeks of testing positive for COVID-19. Among younger adults (ages 18 to 34) who did not require hospitalization and who did not have any underlying health conditions, nearly one in five had not returned to normal health within two to three weeks after testing positive for COVID-19. With severe cases, recovery can take six weeks or more.

Some people may experience longer-term physical, cognitive, and psychological problems. Their symptoms may alternately improve and worsen over time, and can include a variety of difficulties, from fatigue and trouble concentrating to anxiety, muscle weakness, and continuing shortness of breath.

How long after I start to feel better will be it be safe for me to go back out in public again?

The most recent CDC guidance states that someone who has had COVID-19 can discontinue isolation once they have met the following criteria:

  1. It has been more than 10 days since your symptoms began.
  2. You have been fever-free for more than 24 hours without the use of fever-reducing medications.
  3. Other symptoms have improved.

The CDC is no longer recommending a negative COVID-19 test before going back out in public.

Anyone who tested positive for COVID-19 but never experienced symptoms may discontinue isolation 10 days after they first tested positive for COVID-19.

Even after discontinuing isolation, you should still take all precautions when you go out in public, including wearing a mask, minimizing touching surfaces, and keeping at least six feet of distance away from other people.

What's the difference between self-isolation and self-quarantine, and who should consider them?

Self-isolation is voluntary isolation at home by those who have or are likely to have COVID-19 and are experiencing mild symptoms of the disease (in contrast to those who are severely ill and may be isolated in a hospital). The purpose of self-isolation is to prevent spread of infection from an infected person to others who are not infected. If possible, the decision to isolate should be based on physician recommendation. If you have tested positive for COVID-19, you should self-isolate.

You should strongly consider self-isolation if you

  • have been tested for COVID-19 and are awaiting test results
  • have been exposed to the new coronavirus and are experiencing symptoms consistent with COVID-19 (fever, cough, difficulty breathing), whether or not you have been tested.

You may also consider self-isolation if you have symptoms consistent with COVID-19 (fever, cough, difficulty breathing) but have not had known exposure to the new coronavirus and have not been tested for the virus that causes COVID-19. In this case, it may be reasonable to isolate yourself until your symptoms fully resolve, or until you are able to be tested for COVID-19 and your test comes back negative.

Self-quarantine for 14 days by anyone with a household member who has been infected, whether or not they themselves are infected, is the current recommendation of the White House task force. Otherwise, voluntary quarantine at home by those who may have been exposed to the COVID-19 virus but are not experiencing symptoms associated with COVID-19 (fever, cough, difficulty breathing). The purpose of self-quarantine (as with self-isolation) is to prevent the possible spread of COVID-19. When possible, the decision to quarantine should be based on physician recommendation. Self-quarantine is reasonable if you are not experiencing symptoms, but have been exposed to the COVID-19 virus.

What does it really mean to self-isolate or self-quarantine? What should or shouldn't I do?

If you are sick with COVID-19 or think you may be infected with the COVID-19 virus, it is important not to spread the infection to others while you recover. While home-isolation or home-quarantine may sound like a staycation, you should be prepared for a long period during which you might feel disconnected from others and anxious about your health and the health of your loved ones. Staying in touch with others by phone or online can be helpful to maintain social connections, ask for help, and update others on your condition.

Here's what the CDC recommends to minimize the risk of spreading the infection to others in your home and community.

Stay home except to get medical care

  • Do not go to work, school, or public areas.
  • Avoid using public transportation, ride-sharing, or taxis.

Call ahead before visiting your doctor

  • Call your doctor and tell them that you have or may have COVID-19. This will help the healthcare provider's office to take steps to keep other people from getting infected or exposed.

Separate yourself from other people and animals in your home

  • As much as possible, stay in a specific room and away from other people in your home. Use a separate bathroom, if available.
  • Restrict contact with pets and other animals while you are sick with COVID-19, just like you would around other people. When possible, have another member of your household care for your animals while you are sick. If you must care for your pet or be around animals while you are sick, wash your hands before and after you interact with pets and wear a face mask.

Wear a face mask if you are sick

  • Wear a face mask when you are around other people or pets and before you enter a doctor's office or hospital.

Cover your coughs and sneezes

  • Cover your mouth and nose with a tissue when you cough or sneeze and throw used tissues in a lined trash can.
  • Immediately wash your hands with soap and water for at least 20 seconds after you sneeze. If soap and water are not available, clean your hands with an alcohol-based hand sanitizer that contains at least 60% alcohol.

Clean your hands often

  • Wash your hands often with soap and water for at least 20 seconds, especially after blowing your nose, coughing, or sneezing; going to the bathroom; and before eating or preparing food.
  • If soap and water are not readily available, use an alcohol-based hand sanitizer with at least 60% alcohol, covering all surfaces of your hands and rubbing them together until they feel dry.
  • Avoid touching your eyes, nose, and mouth with unwashed hands.

Don't share personal household items

  • Do not share dishes, drinking glasses, cups, eating utensils, towels, or bedding with other people or pets in your home.
  • After using these items, they should be washed thoroughly with soap and water.

Clean all "high-touch" surfaces every day

High touch surfaces include counters, tabletops, doorknobs, bathroom fixtures, toilets, phones, keyboards, tablets, and bedside tables.

  • Clean and disinfect areas that may have any bodily fluids on them.
  • A list of products suitable for use against COVID-19 is available here. This list has been pre-approved by the US Environmental Protection Agency (EPA) for use during the COVID-19 outbreak.

Monitor your symptoms

  • Monitor yourself for fever by taking your temperature twice a day and remain alert for cough or difficulty breathing.
    • If you have not had symptoms and you begin to feel feverish or develop measured fever, cough, or difficulty breathing, immediately limit contact with others if you have not already done so. Call your doctor or local health department to determine whether you need a medical evaluation.
  • Seek prompt medical attention if your illness is worsening, for example if you have difficulty breathing. Before going to a doctor's office or hospital, call your doctor and tell them that you have, or are being evaluated for, COVID-19.
  • Put on a face mask before you enter a healthcare facility or any time you may come into contact with others.
  • If you have a medical emergency and need to call 911, notify the dispatch personnel that you have or are being evaluated for COVID-19. If possible, put on a face mask before emergency medical services arrive.

What types of medications and health supplies should I have on hand for an extended stay at home?

Try to stock at least a 30-day supply of any needed prescriptions. If your insurance permits 90-day refills, that's even better. Make sure you also have over-the-counter medications and other health supplies on hand.

Medical and health supplies

  • prescription medications
  • prescribed medical supplies such as glucose and blood-pressure monitoring equipment
  • fever and pain medicine, such as acetaminophen
  • cough and cold medicines
  • antidiarrheal medication
  • thermometer
  • fluids with electrolytes
  • soap and alcohol-based hand sanitizer
  • tissues, toilet paper, disposable diapers, tampons, sanitary napkins
  • garbage bags.

Should I keep extra food at home? What kind?

Consider keeping a two-week to 30-day supply of nonperishable food at home. These items can also come in handy in other types of emergencies, such as power outages or snowstorms.

  • canned meats, fruits, vegetables, and soups
  • frozen fruits, vegetables, and meat
  • protein or fruit bars
  • dry cereal, oatmeal, or granola
  • peanut butter or nuts
  • pasta, bread, rice, and other grains
  • canned beans
  • chicken broth, canned tomatoes, jarred pasta sauce
  • oil for cooking
  • flour, sugar
  • crackers
  • coffee, tea, shelf-stable milk, canned juices
  • bottled water
  • canned or jarred baby food and formula
  • pet food
  • household supplies like laundry detergent, dish soap, and household cleaner.

When can I discontinue my self-quarantine?

While many experts are recommending 14 days of self-quarantine for those who are concerned that they may be infected, the decision to discontinue these measures should be made on a case-by-case basis, in consultation with your doctor and state and local health departments. The decision will be based on the risk of infecting others.

How can I protect myself while caring for someone that may have COVID-19?

You should take many of the same precautions as you would if you were caring for someone with the flu:

  • Stay in another room or be separated from the person as much as possible. Use a separate bedroom and bathroom, if available.
  • Make sure that shared spaces in the home have good air flow. Turn on an air conditioner or open a window.
  • Wash your hands often with soap and water for at least 20 seconds or use an alcohol-based hand sanitizer that contains 60 to 95% alcohol, covering all surfaces of your hands and rubbing them together until they feel dry. Use soap and water if your hands are visibly dirty.
  • Avoid touching your eyes, nose, and mouth with unwashed hands.
  • Extra precautions:
  • You and the person should wear a face mask if you are in the same room.
  • Wear a disposable face mask and gloves when you touch or have contact with the person's blood, stool, or body fluids, such as saliva, sputum, nasal mucus, vomit, urine.
    • Throw out disposable face masks and gloves after using them. Do not reuse.
    • First remove and throw away gloves. Then, immediately clean your hands with soap and water or alcohol-based hand sanitizer. Next, remove and throw away the face mask, and immediately clean your hands again with soap and water or alcohol-based hand sanitizer.
  • Do not share household items such as dishes, drinking glasses, cups, eating utensils, towels, bedding, or other items with the person who is sick. After the person uses these items, wash them thoroughly.
  • Clean all "high-touch" surfaces, such as counters, tabletops, doorknobs, bathroom fixtures, toilets, phones, keyboards, tablets, and bedside tables, every day. Also, clean any surfaces that may have blood, stool, or body fluids on them. Use a household cleaning spray or wipe.
  • Wash laundry thoroughly.
    • Immediately remove and wash clothes or bedding that have blood, stool, or body fluids on them.
    • Wear disposable gloves while handling soiled items and keep soiled items away from your body. Clean your hands immediately after removing your gloves.
  • Place all used disposable gloves, face masks, and other contaminated items in a lined container before disposing of them with other household waste. Clean your hands (with soap and water or an alcohol-based hand sanitizer) immediately after handling these items.

My parents are older, which puts them at higher risk for COVID-19, and they don't live nearby. How can I help them if they get sick?

Caring from a distance can be stressful. Start by talking to your parents about what they would need if they were to get sick. Put together a single list of emergency contacts for their (and your) reference, including doctors, family members, neighbors, and friends. Include contact information for their local public health department.

You can also help them to plan ahead. For example, ask your parents to give their neighbors or friends a set of house keys. Have them stock up on prescription and over-the counter medications, health and emergency medical supplies, and nonperishable food and household supplies. Check in regularly by phone, Skype, or however you like to stay in touch.

Can people infect pets with the COVID-19 virus?

The virus that causes COVID-19 does appear to spread from people to pets, according to the FDA. Research has found that cats and ferrets are more likely to become infected than dogs.

If you have a pet, do the following to reduce their risk of infection:

  • Avoid letting pets interact with people or animals that do not live in your household.
  • Keep cats indoors when possible to prevent them from interacting with other animals or people.
  • Walk dogs on a leash maintaining at least six feet from other people and animals.
  • Avoid dog parks or public places where a large number of people and dogs gather.

If you become sick with COVID-19, restrict contact with your pets, just like you would around other people. This means you should forgo petting, snuggling, being kissed or licked, and sharing food or bedding with your pet until you are feeling better. When possible, have another member of your household care for your pets while you are sick. If you must care for your pet while you are sick, wash your hands before and after you interact with your pets and wear a face mask.

At present, it is considered unlikely that pets can spread the COVID-19 virus to humans. However, pets can spread other infections that cause illness, including E. coli and Salmonella, so wash your hands thoroughly with soap and water after interacting with your animal companions.

Blog post:

Podcast:

You think you've got COVID-19. Here's what you need to do (recorded 4/10/20)

We asked Dr. Mallika Marshall, medical reporter for CBS-affiliate WBZ TV in Boston and an instructor at Harvard Medical School, how we should react when we start to experience a dry cough or perhaps spike a fever. Who do you call? How do you protect your family? When does it make sense to move toward an emergency department, and how should we prepare? Dr. Marshall is the host of Harvard Health Publishing's online course series, and an urgent care physician at Mass General Hospital.

For more information on coronavirus and COVID-19, see the Harvard Health Publishing Coronavirus Resource Center.

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