Coronavirus Resource Center

As coronavirus spreads, many questions and some answers

The rapid spread of the virus that causes COVID-19 has sparked alarm worldwide. The World Health Organization (WHO) has declared this rapidly spreading coronavirus outbreak a pandemic, and countries around the world are grappling with a surge in confirmed cases. In the US, social distancing to slow the spread of coronavirus has created a new normal. Meanwhile, scientists are exploring potential treatments and are beginning clinical trials to test new therapies and vaccines. And hospitals are ramping up their capabilities to care for increasing numbers of infected patients.

Below, you'll find answers to common questions all of us are asking. We will be adding new questions and updating answers as reliable information becomes available. Also see our podcasts featuring experts discussing coronavirus and COVID-19.

Symptoms, spread, and other essential information

What is coronavirus and how does it spread? What is COVID-19 and what are the symptoms? How long does coronavirus live on different surfaces? Take a moment to reacquaint yourself with basic information about this virus and the disease it causes.

Click here to read more about COVID-19 symptoms, spread, and other basic information.

Social distancing, hand washing, and other preventive measures

By now, many of us are taking steps to protect ourselves from infection. This likely includes frequent handwashing, regularly cleaning frequently touched surfaces, and social distancing. How do each of these measures help slow the spread of this virus, and is there anything else you can do?

Click here to read more about what you can do to protect yourself and others from coronavirus infection.

If you are at higher risk

Though no one is invulnerable, we've seen that older adults are at increased risk for severe illness or death from COVID-19. Underlying conditions, including heart disease, lung disease, and diabetes, increase risk even further in those who are older. In addition, anyone with an underlying medical condition, regardless of their age, faces increased risk of serious illness.

Click here to read more about what you can do if you are at increased risk for serious illness.

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

Despite your best efforts, you may be exposed to coronavirus and become ill with COVID-19. Or you may be in a position where you are caring for a loved one with the disease. It's important to know what to do if you find yourself in any of these situations. Stock up with medications and health supplies now, and learn the steps you can take to avoid infecting others in your household and to avoid getting sick yourself if you are caring for someone who is ill.

Click here to read more about what to do you if you have been exposed, are sick, or are caring for someone with COVID-19.

Treatments for COVID-19: What helps, what doesn't, and what's in the pipeline

While there are no specific treatments for COVID-19 at this time, there are things you can do to feel better if you become ill. In the meantime, researchers around the globe are looking at existing drugs to see if they may be effective against the virus that causes COVID-19, and are working to develop new treatments as well.

Click here to read more about measures that can help you feel better and treatments that are under investigation.

Coronavirus and kids:

So far, the vast majority of coronavirus infections have afflicted adults. And when kids are infected, they tend to have milder disease. Still, as a parent, you can't help but worry about the safety of your children. Many parents are also trying to find a balance between answering their children's questions about the pandemic and enforcing health-promoting behaviors and social distancing rules without creating an atmosphere of anxiety. Not to mention keeping kids engaged and entertained with schools closed and playdates cancelled.

Click here to read more about kids and the coronavirus outbreak.

Coping with coronavirus:

The news about coronavirus and its impact on our day-to-day lives has been unrelenting. There's reason for concern and it makes good sense to take the pandemic seriously. But it's not good for your mind or your body to be on high alert all the time. Doing so will wear you down emotionally and physically.

Click here to read more about coping with coronavirus.

New questions and answers

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.

Are chloroquine/hydroxychloroquine and azithromycin safe and effective for treating COVID-19?

Early reports from China and France suggested that patients with severe symptoms of COVID-19 improved more quickly when given chloroquine or hydroxychloroquine. Some doctors were using a combination of hydroxychloroquine and azithromycin with some positive effects.

Hydroxychloroquine and chloroquine are primarily used to treat malaria and several inflammatory diseases, including lupus and rheumatoid arthritis. Azithromycin is a commonly prescribed antibiotic for strep throat and bacterial pneumonia. Both drugs are inexpensive and readily available.

Hydroxychloroquine and chloroquine have been shown to kill the COVID-19 virus in the laboratory dish. The drugs appear to work through two mechanisms. First, they make it harder for the virus to attach itself to the cell, inhibiting the virus from entering the cell and multiplying within it. Second, if the virus does manage to get inside the cell, the drugs kill it before it can multiply.

Azithromycin is never used for viral infections. However, this antibiotic does have some anti-inflammatory action. There has been speculation, though never proven, that azithromycin may help to dampen an overactive immune response to the COVID-19 infection.

However, the most recent human studies suggest no benefit — and possibly a higher risk of death due to lethal heart rhythm abnormalities — with both hydroxychloroquine and azithromycin used alone. The drugs are especially dangerous when used in combination.

Based on these new reports, the FDA now formally recommends against taking chloroquine or hydroxychloroquine for COVID-19 infection unless it is being prescribed in the hospital or as part of a clinical trial. Three days earlier a National Institutes of Health (NIH) panel released a similar strong statement advising against the use of the combination of hydroxychloroquine and azithromycin.

How could contact tracing help slow the spread of COVID-19?

Anyone who comes into close contact with someone who has COVID-19 is at increased risk of becoming infected themselves, and of potentially infecting others. Contact tracing can help prevent further transmission of the virus by quickly identifying and informing people who may be infected and contagious, so they can take steps to not infect others.

Contact tracing begins with identifying everyone that a person recently diagnosed with COVID-19 has been in contact with since they became contagious. In the case of COVID-19, a person may be contagious 48 to 72 hours before they started to experience symptoms.

The contacts are notified about their exposure. They may be told what symptoms to look out for, advised to isolate themselves for a period of time, and to seek medical attention as needed if they start to experience symptoms.

Will warm weather slow or stop the spread of COVID-19?

Some viruses, like the common cold and flu, spread more when the weather is colder. But it is still possible to become sick with these viruses during warmer months.

At this time, we do not know for certain whether the spread of COVID-19 will decrease when the weather warms up. But a new report suggests that warmer weather may not have much of an impact.

The report, published in early April by the National Academies of Sciences, Engineering and Medicine, summarized research that looked at how well the COVID-19 coronavirus survives in varying temperatures and humidity levels, and whether the spread of this coronavirus may slow in warmer and more humid weather.

The report found that in laboratory settings, higher temperatures and higher levels of humidity decreased survival of the COVID-19 coronavirus. However, studies looking at viral spread in varying climate conditions in the natural environment had inconsistent results.

The researchers concluded that conditions of increased heat and humidity alone may not significantly slow the spread of the COVID-19 virus.

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 is convalescent plasma? How could it help people with COVID-19?

When people recover from COVID-19, their blood contains antibodies that their bodies produced to fight the coronavirus and help them get well. Antibodies are found in plasma, a component of blood.

Convalescent plasma — literally plasma from recovered patients — has been used for more than 100 years to treat a variety of illnesses from measles to polio, chickenpox, and SARS. In the current situation, antibody-containing plasma from a recovered patient is given by transfusion to a patient who is suffering from COVID-19. The donor antibodies help the patient fight the illness, possibly shortening the length or reducing the severity of the disease.

Though convalescent plasma has been used for many years, and with varying success, not much is known about how effective it is for treating COVID-19. There have been reports of success from China, but no randomized, controlled studies (the gold standard for research studies) have been done. Experts also don't yet know the best time during the course of the illness to give plasma.

On March 24th, the FDA began allowing convalescent plasma to be used in patients with serious or immediately life-threatening COVID-19 infections. This treatment is still considered experimental.

Who can donate plasma for COVID-19?

In order to donate plasma, a person must meet several criteria. They have to have tested positive for COVID-19, recovered, have no symptoms for 14 days, currently test negative for COVID-19, and have high enough antibody levels in their plasma. A donor and patient must also have compatible blood types. Once plasma is donated, it is screened for other infectious diseases, such as HIV.

Each donor produces enough plasma to treat one to three patients. Donating plasma should not weaken the donor's immune system nor make the donor more susceptible to getting reinfected with the virus.

Can COVID-19 affect brain function?

COVID-19 does appear to affect 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.

One study that looked at 214 people with moderate to severe COVID-19 in Wuhan, China found that about one-third of those patients had one or more neurological symptoms. Neurological symptoms were more common in people with more severe disease.

Neurological symptoms have also been seen in COVID-19 patients in the US and around the world. Some people with neurological symptoms tested positive for COVID-19 but did not have any respiratory symptoms like coughing or difficulty breathing; others experienced both neurological and respiratory symptoms.

Experts do not know how the coronavirus causes neurological symptoms. They may be a direct result of infection or an indirect consequence of inflammation or altered oxygen and carbon dioxide levels caused by the virus.

The CDC has added "new confusion or inability to rouse" to its list of emergency warning signs that should prompt you to get immediate medical attention.

What precautions can I take when grocery shopping?

The coronavirus that causes COVID-19 is primarily transmitted through droplets containing virus, or through viral particles that float in the air. The virus may be breathed in directly and can also spread when a person touches a surface or object that has the virus on it and then touches their mouth, nose, or eyes. There is no current evidence that the COVID-19 virus is transmitted through food.

Safety precautions help you avoid breathing in coronavirus or touching a contaminated surface and touching your face.

In the grocery store, maintain at least six feet of distance between yourself and other shoppers. Wipe frequently touched surfaces like grocery carts or basket handles with disinfectant wipes. Avoid touching your face. Wearing a cloth mask helps remind you not to touch your face and can further help reduce spread of the virus. Use hand sanitizer before leaving the store. Wash your hands as soon as you get home.

If you are older than 65 or at increased risk for any reason, limit trips to the grocery store. Ask a neighbor or friend to pick up groceries and leave them outside your house. See if your grocery store offers special hours for older adults or those with underlying conditions. Or have groceries delivered to your home.

What precautions can I take when unpacking my groceries?

Recent studies have shown that the COVID-19 virus may remain on surfaces or objects for up to 72 hours. This means virus on the surface of groceries will become inactivated over time after groceries are put away. If you need to use the products before 72 hours, consider washing the outside surfaces or wiping them with disinfectant. The contents of sealed containers won't be contaminated.

After unpacking your groceries, wash your hands with soap and water for at least 20 seconds. Wipe surfaces on which you placed groceries while unpacking them with household disinfectants.

Thoroughly rinse fruits and vegetables with water before consuming. And wash your hands before consuming any foods that you've recently brought home from the grocery store.

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.

More about COVID-19

Podcast: COVID-19 therapies update: There are three potential pathways forming a bridge to a vaccine (recorded 4/13/20)

You've probably heard the anti-malarial drug hydroxychloroqine is getting a hard look as a potential therapeutic agent in the fight against COVID-19. However, as Harvard Health Publishing senior faculty editor Dr. Rob Shmerling points out, evidence remains weak. On the brighter side, he points to three potential avenues in COVID-19 research where therapies may be put to use while a vaccine remains in development.

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.

Podcast: Coping with coronavirus: How to get some exercise--safely--at home while sheltering in place (recorded 4/8/20)

We all know we need to try to keep moving during these unusual times of social distancing, but where do we start? We consulted Heidi Godman, executive editor of Harvard Health Letter, who's been researching this subject. Bottom line? Keep it simple.

Reliable resources

Terms to know:

aerosols: infectious viral particles that can float or drift around in the air. Aerosols are emitted by a person infected with coronavirus — even one with no symptoms — when they talk, breathe, cough, or sneeze. Another person can breathe in these aerosols and become infected with the virus. Aerosolized coronavirus can remain in the air for up to three hours. A mask can help prevent that spread.

community spread (community transmission): is said to have occurred when people have been infected without any knowledge of contact with someone who has the same infection

contact tracing: a process that begins with identifying everyone a person diagnosed with a given illness (in this case COVID-19) has been in contact with since they became contagious. The contacts are notified that they are at risk, and may include those who share the person's home, as well as people who were in the same place around the same time as the person with COVID-19 — a school, office, restaurant, or doctor's office, for example. Contacts may be quarantined or asked to isolate themselves if they start to experience symptoms, and are more likely to be tested for coronavirus if they begin to experience symptoms.

containment: refers to limiting the spread of an illness. Because no vaccines exist to prevent COVID-19 and no specific therapies exist to treat it, containment is done using public health interventions. These may include identifying and isolating those who are ill, and tracking down anyone they have had contact with and possibly placing them under quarantine.

epidemic: a disease outbreak in a community or region

flattening the curve: refers to the epidemic curve, a statistical chart used to visualize the number of new cases over a given period of time during a disease outbreak. Flattening the curve is shorthand for implementing mitigation strategies to slow things down, so that fewer new cases develop over a longer period of time. This increases the chances that hospitals and other healthcare facilities will be equipped to handle any influx of patients.

incubation period: the period of time between exposure to an infection and when symptoms begin

isolation: the separation of people with a contagious disease from people who are not sick

mitigation: refers to steps taken to limit the impact of an illness. Because no vaccines exist to prevent COVID-19 and no specific therapies exist to treat it, mitigation strategies may include frequent and thorough handwashing, not touching your face, staying away from people who are sick, social distancing, avoiding large gatherings, and regularly cleaning frequently touched surfaces and objects at home, in schools, at work, and in other settings.

pandemic: a disease outbreak affecting large populations or a whole region, country, or continent

physical distancing: also called social distancing, refers to actions taken to stop or slow down the spread of a contagious disease. For an individual, it refers to maintaining enough physical distance (a minimum of six feet) between yourself and another person to reduce the risk of breathing in droplets or aerosols that are produced when an infected person breathes, talks, coughs, or sneezes.

presumptive positive test result: a positive test for the virus that causes COVID-19, performed by a local or state health laboratory, is considered "presumptive" until the result is confirmed by the CDC. While awaiting confirmation, people with a presumptive positive test result will be considered to be infected.

quarantine: separates and restricts the movement of people who have a contagious disease, have symptoms that are consistent with the disease, or were exposed to a contagious disease, to see if they become sick

SARS-CoV-2: short for severe acute respiratory syndrome coronavirus 2, SARS-CoV-2 is the official name for the virus responsible for COVID-19.

social distancing: also called physical distancing, refers to actions taken to stop or slow down the spread of a contagious disease. For an individual, it refers to maintaining enough physical distance (a minimum of six feet) between yourself and another person to reduce the risk of breathing in droplets or aerosols that are produced when an infected person breathes, talks, coughs, or sneezes. It is possible to safely maintain social connections while social distancing, through phone calls, video chats, and social media platforms.

virus: a virus is the smallest of infectious microbes, smaller than bacteria or fungi. A virus consists of a small piece of genetic material (DNA or RNA) surrounded by a protein shell. Viruses cannot survive without a living cell in which to reproduce. Once a virus enters a living cell (the host cell) and takes over a cell's inner workings, the cell cannot carry out its normal life-sustaining tasks. The host cell becomes a virus manufacturing plant, making viral parts that then reassemble into whole viruses and go on to infect other cells. Eventually, the host cell dies.

Image: Naeblys/Getty Images

Questions?

Harvard Health Publishing Coronavirus Resource Center Experts

The Harvard Health Publishing team would like to acknowledge the Harvard Medical School experts who have contributed their time and expertise: Ashwini Bapat, MD; Suzanne Bertisch, MD, MPH; Emeric Bojarski, MD; Todd Ellerin, MD; Huma Farid, MD; Robert Gabbay, MD, PhD, FACP; Ellen S. Glazer, LICSW; Peter Grinspoon, MD; Anthony Komaroff, MD; Douglas Krakower, MD; Debi LaPlante, PhD; Howard E. LeWine, MD; Dara K. Lee Lewis, MD; Kristina Liu, MD, MHS; Luana Marques, PhD; Claire McCarthy, MD; Babar Memon, MD, MSc; Uma Naidoo, MD; Janelle Nassim, MD; Edward Phillips, MD; Lee H. Schwamm, MD; Howard J. Shaffer, PhD, CAS; John Sharp, MD; Robert H. Shmerling, MD; Jacqueline Sperling, PhD; Monique Tello, MD, MPH; Anna R. Wolfson, MD.

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