Coronavirus Resource Center

As coronavirus spreads, many questions and some answers

The rapid spread of the virus that causes COVID-19 continues to spark alarm worldwide. Countries around the world are grappling with surges in confirmed cases, hospitalizations, and deaths. Calls for preventive measures such as social distancing and face coverings to slow the spread of coronavirus have created a new normal in many places. Health care workers and hospitals have ramped up capabilities to care for large numbers of people made seriously ill by COVID-19. Meanwhile, scientists are exploring potential treatments and clinical trials to test new therapies and vaccines are underway.

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

When can I discontinue my self-quarantine?

A full, 14-day quarantine remains the best way to ensure that you don't spread the virus to others after you've been exposed to someone with COVID-19. However, according to CDC guidelines, you may discontinue quarantine after a minimum of 10 days if you do not have any symptoms, or after a minimum of 7 days if you have a negative COVID test within 48 hours of when you plan to end quarantine.

Who will get the first COVID-19 vaccines?

Healthcare workers and residents and staff of long-term care facilities will get the first COVID-19 vaccines once the vaccines are granted Emergency Use Authorization (EUA).

There are about 21 million healthcare workers in the US, doing a variety of jobs in hospitals and outpatient clinics, pharmacies, emergency medical services, and public health. Another three million people reside or work in long-term care facilities, which include nursing homes, assisted-living facilities, and residential care facilities. COVID-19 has taken a heavy toll on residents of long-term care facilities.

Both Pfizer/BioNTech and Moderna have applied to the FDA for EUA of their vaccines. Pfizer's vaccine is expected to receive EUA in mid-December, and Moderna's vaccine soon after. Both of these vaccines require two doses spaced a few weeks apart. The companies estimate that they will have enough to vaccinate about 20 million people by the end of December, with vaccine production continuing to ramp up in early 2021. Other vaccines, including one by AstraZeneca, are also on the horizon.

The next priority groups for vaccination are expected to include essential workers, adults with underlying medical conditions that increase risk for severe COVID-19, and adults over age 65.

The CDC's guidance is based on a recommendation from the Advisory Committee on Immunization Practices (ACIP), made up of experts in vaccinology, immunology, virology, public health, and other related fields. Their work is not limited to the COVID-19 vaccine; they broadly advise the CDC on vaccinations and immunization schedules.

What are adenovirus vaccines? What do we know about adenovirus vaccines that are being developed for COVID-19?

Adenoviruses can cause a variety of illnesses, including the common cold. They are being used in two leading COVID-19 vaccine candidates as capsules (the scientific term is vectors) to deliver the coronavirus spike protein into the body. The spike protein prompts the immune system to produce antibodies against it, preparing the body to attack the SARS-CoV-2 virus if it later infects the body.

In a press release, AstraZeneca announced promising preliminary results of an adenovirus-based vaccine that it developed with researchers at the University of Oxford.

The preliminary analysis was based on more than 23,000 adult study participants enrolled in a phase 3 clinical trial. Of these, nearly 9,000 participants received a full dose of the coronavirus vaccine, followed four weeks later by another full dose. Nearly 3,000 participants received a half dose of the coronavirus vaccine, followed four weeks later by a full dose. The control group received a meningitis vaccine, followed by a second meningitis vaccine or a placebo (a saltwater shot). There were 131 documented cases of COVID-19, all of which occurred at least two weeks after the second shot.

The coronavirus vaccine reduced the risk of COVID-19 by an average of 70.4%, compared to the control group. Surprisingly, the half dose/full dose vaccine combination was more effective, reducing risk of COVID-19 by 90%. The full dose combination reduced risk by 62%. None of the participants who received the coronavirus vaccine developed severe COVID-19 or had to be hospitalized. There was also a reduction in asymptomatic cases.

All study participants were healthy or had stable underlying medical conditions. This vaccine is in clinical trials around the world, including the US. But this analysis was based on data from the United Kingdom and Brazil.

The adenovirus used in the AstraZeneca/University of Oxford vaccine is a weakened, harmless form of a chimpanzee common-cold adenovirus. This vaccine can be safely refrigerated for several months.

What are monoclonal antibodies? Can they help treat COVID-19?

The FDA has granted emergency use authorization (EUA) to two new treatments for COVID-19. Both are monoclonal antibodies. And both have been approved to treat non-hospitalized adults and children over age 12 with mild to moderate symptoms who have recently tested positive for COVID-19, and who are at risk for developing severe COVID-19 or being hospitalized for it. This includes people over 65, people with obesity, and those with certain chronic medical conditions.

The FDA granted EUA to the first treatment, a monoclonal antibody called bamlanivimab made by Eli Lilly, based on an interim analysis of results from a well-designed but small clinical trial. The study looked at 465 non-hospitalized adults with mild to moderate COVID-19 symptoms who were at high risk of severe disease. A placebo was given to 156 of these patients. The remaining patients were given one of three different doses of bamlanivimab. Patients treated with the monoclonal antibody had a reduced risk (3% versus 10%) of being hospitalized or visiting the ER within 28 days after treatment, compared to patients given a placebo. This is a single-dose treatment that must be given intravenously and within 10 days of developing symptoms.

The FDA has also granted EUA to a combination therapy consisting of two monoclonal antibodies, casirivimab and imdevimab, made by Regeneron. The EUA was based on results from a clinical trial that enrolled 799 non-hospitalized adults with mild to moderate COVID-19 symptoms. The participants were divided into three groups, two of which received the casirivimab-imdevimab combination but at different doses. The third group received a placebo. For patients at high risk for severe disease, those treated with the monoclonal antibody treatment had a reduced risk (3% versus 9%) of being hospitalized or visiting the ER within 28 days of treatment. This treatment must also be given intravenously in a clinic or hospital.

Monoclonal antibodies are manmade versions of the antibodies that our bodies naturally make to fight invaders, such as the SARS-CoV-2 virus. Both of these FDA-approved therapies attack the coronavirus's spike protein, making it more difficult for the virus to attach to and enter human cells.

These treatments are not authorized for hospitalized COVID-19 patients or those receiving oxygen therapy. They have not shown to benefit these patients and could lead to worse outcomes in these patients.

Is there an at-home diagnostic test for COVID-19?

The FDA has approved the first diagnostic test for COVID-19 that can be completed entirely at home, from sample collection to receiving the results. Other FDA-approved COVID-19 tests allow at-home sample collection, but still have to be shipped to a laboratory for processing.

The Lucira COVID-19 All-In-One Test Kit is approved for people ages 14 and older who are suspected of having COVID-19. It requires a doctor's prescription. The company does not expect the test to be widely available until the spring of 2021.

To perform the test, you swirl a swab in both nostrils, then stir the swab in a vial of chemicals. The vial is then plugged into a battery-powered test unit, which returns a positive or negative test result within 30 minutes.

The test works by making copies of the virus's genetic material (if present) until it reaches detectable levels. It does this using a technique called loop-mediated isothermal amplification (LAMP). The method is similar to PCR, the gold standard of COVID-19 diagnostic testing. The LAMP test provides much faster results, but it is less accurate. In a head-to-head comparison, the Lucira test missed 6% of people who tested positive for COVID by PCR.

Because a person can be infected and have a negative LAMP test, you should always self-quarantine if you have symptoms consistent with COVID, or have had recent contact with someone who has the infection, until you can get a PCR test.

What are mRNA vaccines? What do we know about mRNA vaccines that are being developed for COVID-19?

mRNA, or messenger RNA, is genetic material that contains instructions for making proteins. mRNA vaccines for COVID-19 contain synthetic mRNA. Inside the body, the mRNA enters human cells and instructs them to produce the "spike" protein found on the surface of SARS-CoV-2, the virus that causes COVID-19. The body recognizes the spike protein as an invader, and produces antibodies against it. If the antibodies later encounter the actual virus, they are ready to recognize and destroy it before it causes illness.

In the past couple of weeks, two companies have released promising data about their mRNA vaccines. Results for both vaccines were reported in company press releases, not in peer reviewed scientific journals.

One of the mRNA vaccines was developed by Pfizer and BioNTech. Their phase 3 clinical trial found that their vaccine reduced the risk of infection by 95%. The trial enrolled nearly 44,000 adults. Of these, half received the vaccine and half got a placebo (a shot of saltwater). Of the 170 cases of COVID-19 that developed in the study participants, 162 were in the placebo group and eight were in the vaccine group. Nine of the 10 severe COVID cases occurred in the placebo group. This suggests that the vaccine reduces risk of both mild and severe COVID. The vaccine was consistently effective across age, race, and ethnicity. Of the US study participants, 30% were people of color and 45% were age 56 to 85.

The other mRNA vaccine, developed by Moderna, released an interim analysis of its phase 3 trial, announcing that its vaccine was 94.5% effective. This study enrolled 30,000 adults; half received the vaccine, half received a saltwater placebo shot. There were 95 infections among the study participants. Of these, 90 were in the placebo group and 5 were in the vaccine group. All 11 severe COVID cases occurred in the placebo group. This vaccine also appears to reduce risk of mild and severe illness. And it was effective in older people, people with medical conditions that put them at high risk for severe illness, and in racial and ethnic minorities, which made up 37% of the study participants. The study enrolled more than 7,000 participants older than 65, and more than 5,000 people under 65 who were at high risk for severe illness.

Both vaccines had a good safety record. Side effects included fatigue, headache, and muscle pain.

These results are promising, but there are still questions left to be answered. For example, we do not yet know how long immunity from these vaccines will last. Both of these vaccines require two doses (three weeks between shots for the Pfizer vaccine and four weeks between shots for the Moderna vaccine), and we don't know how effective the vaccine is in people who only get one dose. There is also the question of storage. mRNA vaccines must be stored at very cold temperatures, and improperly stored vaccines can become inactive.

Do pregnant women face increased risks from COVID-19?

A large study from the CDC has found that pregnant women are at increased risk of severe COVID-19 illness compared to women who are not pregnant.

The study looked at 409,462 women, ages 15 to 44, who had symptomatic COVID-19. Of these women, 23,434 were pregnant. Even after taking age, race, ethnicity, and underlying health conditions into consideration, pregnant women were significantly more likely to need intensive care, to require a ventilator, and to require a heart-lung bypass machine, compared to women who were not pregnant. They were also 70% more likely to die.

It's important to note that the overall risk of these complications was low. For example, 1.5 symptomatic pregnant women out of 1,000 died, compared to 1.2 symptomatic women out of 1,000 who were not pregnant.

The CDC also released a smaller study, which found that women who were infected with the COVID-19 virus during pregnancy were more likely to deliver preterm (earlier than 37 weeks).

If you are pregnant, be vigilant about taking precautions. Wear a mask, physically distance from others, and avoid social gatherings. Do your best to follow the CDC's recommendations to protect yourself if someone in your household becomes infected.

Continue to see your doctor for prenatal visits and get any recommended vaccines. Call your doctor's office to discuss safety precautions if you have concerns.

Could wearing masks prevent COVID deaths?

According to a new study published in the journal Nature Medicine, widespread use of masks could prevent nearly 130,000 of 500,000 COVID-related deaths estimated to occur by March 2021.

These numbers are based on an epidemiological model. The researchers considered, state by state, the number of people susceptible to coronavirus infection, how many get exposed, how many then become infected (and infectious), and how many recover. They then modeled various scenarios, including mask wearing, assuming that social distancing mandates would go into effect once the number of deaths exceeded 8 per 1 million people.

Modeling studies are based on assumptions, so the exact numbers are less important than the comparisons of different scenarios. In this study, a scenario in which 95% of people always wore masks in public resulted in many fewer deaths compared to a scenario in which only 49% of people (the self-reported national average of mask wearers) always wore masks in public.

This study reinforces the message that we can help prevent COVID deaths by wearing masks.

What does the CDC's new definition of "close contacts" mean for me?

The CDC has expanded how it defines close contacts of someone with COVID-19. Until this point, the CDC had defined a close contact as someone who spent 15 or more consecutive minutes within six feet of someone with COVID-19. According to the new definition, a close contact is someone who spends 15 minutes or more within six feet of a person with COVID-19 over a period of 24 hours.

Close contacts are at increased risk of infection. When a person tests positive for COVID-19, contact tracers may identify their close contacts and urge them to quarantine to prevent further spread. Based on the new definition, more people will now be considered close contacts.

Many factors can affect the chances that infection will spread from one person to another. These factors include whether or one or both people are wearing masks, whether the infected person is coughing or showing other symptoms, and whether the encounter occurred indoors or outdoors. Though the "15 minutes within six feet rule" is a helpful guideline, it's always best to minimize close interactions with people who are not members of your household.

The CDC's new definition was influenced by a case described in the CDC's Morbidity and Mortality Weekly Report in which a correctional officer in Vermont is believed to have been infected after being within six feet for 17 non-consecutive minutes of six asymptomatic individuals, all of whom later tested positive for COVID-19.

How does obesity increase risk of COVID-19?

According to a recent review and meta-analysis that looked at 75 international studies on the subject, obesity is a significant risk factor for illness and death due to COVID-19.

When looking at people with COVID-19, the analysis found that, compared with people who were normal weight or overweight, people who were obese were

  • more than twice as likely to be hospitalized
  • if hospitalized, nearly 75% more likely to be admitted to the intensive care unit (ICU)
  • almost 50% more likely to die of COVID-19.

Obesity may impact COVID risk in several ways. For example, obesity increases the risk of impaired immune function and chronic inflammation, both of which could make it harder for the body to fight the COVID-19 infection. Excess fat can also make it harder for a person to take a deep breath, an important consideration for an illness that impairs lung function.

People who are obese are also more likely to have diabetes and high blood pressure, which are themselves risk factors for severe COVID-19. And obesity is more common in Black, Latinx, and Native Americas, who are more likely to get infected and die from COVID-19 than whites for a variety of reasons.

If you have obesity (defined as a body mass index, or BMI, of 30 or higher), stay vigilant about protecting yourself from infection. That means maintaining physical distance, avoiding crowds when possible, wearing masks, and washing your hands often.


More about COVID-19


Podcast: Thoughts on COVID-19 during this year's flu season (recorded 10/9/2020)

With the COVID-19 pandemic still ongoing, and the annual flu season fast approaching, what can people expect when these two illnesses collide? Are we at greater risk for getting either virus? And could this encounter change how we approach health care now and in the future? Matthew Solan, executive editor of the Harvard Men's Health Watch, talks to Dr. Amy Sherman, an infectious disease expert with Harvard's Brigham and Women's Hospital, about what we may expect when COVID and the flu season meet. To learn more check out our Harvard Medical School Guide, COVID-19, Flu and Colds.

Podcast: Back to school: It's never been more complicated (recorded 7/30/2020)

Sending kids back to school in the fall is always a hopeful time in America. For most families, school is a vital part of the community. With the surge in coronavirus in many areas of the country, getting kids back in the classroom safely will require a major re-evaluation to reduce transmission rates that can impact people of all ages. We talked to Allan Geller, a senior lecturer in the Department of Social and Behavioral Sciences at Harvard's T.H. Chan School of Public Health. Like it or not, for school teachers and administrators, things are going to be different. Don't expect the traditional.

Podcast: Coronavirus Update: We're facing the start of a second wave (recorded 6/11/2020)

Dr. Ashish K. Jha, head of the Harvard Global Health Institute, offers information on where we are where we're going with the COVID-19 outbreak. Some take-aways:

  • Communications missteps by the WHO regarding asymptomatic transmission have been quickly corrected. Yes, you can catch COVID-19 from people who are not showing symptoms.
  • A second wave has begun, particularly in the south and Midwest. And calculations show we'll reach more than 200,000 COVID-19 related deaths by September.
  • Jha offers advice for parents, teachers and administrators on workable back-to-school scenarios.
  • We know you don't want to hear it, but COVID-19 will be a fact of global life for the rest of the year until a vaccine becomes widely available.


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: Steven A. Adelman, MD; Ashwini Bapat, MD; Suzanne Bertisch, MD, MPH; Joseph R. Betancourt, MD, MPH; Barry R. Bloom, PhD; Emeric Bojarski, MD; Andrew E. Budson, MD; Stephanie Collier, MD, MPH; Todd Ellerin, MD; Huma Farid, MD; Robert Gabbay, MD, PhD, FACP; Alan Geller, MPH, RN; Ellen S. Glazer, LICSW; Peter Grinspoon, MD; Abraar Karan, MD, MPH, DTM&H; Sabra L. Katz-Wise, PhD; Alyson Kelley-Hedgepeth, MD; Anthony Komaroff, MD; Douglas Krakower, MD; Debi LaPlante, PhD; Howard E. LeWine, MD; Dara K. Lee Lewis, MD; Sharon Levy, MD, MPH; Kristina Liu, MD, MHS; Julia Marcus, PhD, MPH; Luana Marques, PhD; Claire McCarthy, MD; Chris McDougle, MD; Babar Memon, MD, MSc; Uma Naidoo, MD; Janelle Nassim, MD; Vikram Patel, MBBS, PhD; Edward Phillips, MD; Shiv Pillai, PhD, MBBS; John Ross, MD, FIDSA; Lee H. Schwamm, MD; Catherine Ullman Shade, PhD, MEd; Howard J. Shaffer, PhD, CAS; Roger Shapiro, MD, MPH; John Sharp, MD; Robert H. Shmerling, MD; Jacqueline Sperling, PhD; Fatima Cody Stanford, MD, MPH, MPA, FAAP, FACP, FTOS; Monique Tello, MD, MPH; Robyn Thom, MD; Karen Turner, OTR/L; Rochelle Wallensky, MD, MPH; Janice Ware, PhD; Scott Weiner, MD; Sarah Wilkie, MS; Anna R. Wolfson, MD.

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