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COVID-19 | School of Public Health Expert Insights


School of Public Health Expert Insights

Coronavirus Questions and Answers


Coronavirus: The Basics

What is a coronavirus?

Coronaviruses are a family of viruses that typically cause mild respiratory infections like the common cold, but also more severe (and potentially deadly) infections. They are zoonotic diseases, meaning they are transmitted from animals to people.

SOURCE: Global Health NOW

Why is it called a coronavirus?

Coronaviruses are named after the Latin word corona, meaning “crown” or “halo,” because they have “crown-like spikes on their surface,” according to the U.S. Centers for Disease Control and Prevention.

SOURCE: Global Health NOW

What severe diseases are caused by coronaviruses?

A coronavirus that originated in China led to the Severe Acute Respiratory Syndrome (SARS) outbreak in 2003. Another coronavirus emerged in 2012 in Saudi Arabia, causing Middle East Respiratory Syndrome (MERS).

SOURCE: Global Health NOW

What’s the difference between coronavirus, SARS-CoV-2, and COVID-19?

The novel coronavirus responsible for this outbreak is known as SARS-CoV-2. The illness caused by the virus is called COVID-19.

More information can be found here: Naming the coronavirus disease (COVID-19) and the virus that causes it—WHO.

SOURCE: Global Health NOW

Could COVID-19 or a variant have been here before January 2020?

We don’t know yet when the virus first came to the United States. We don’t have any evidence yet that it was here in December but we also don’t have evidence that it wasn’t here.

There has been one case in France that may have occurred in December, but that’s really the only evidence so far that the virus may have been outside of China prior to January.

SOURCE: Jennifer Nuzzo

What symptoms do coronaviruses typically cause? How is COVID-19 different?

Common signs of coronavirus infection include runny nose, cough, fever, sore throat, and shortness of breath.

COVID-19 can cause a wide range of signs and symptoms at varying levels of severity. The most common are fever, dry cough, and tiredness. Other symptoms include shortness of breath or difficulty breathing, muscle aches, chills, sore throat, headache or chest pain.

Other symptoms that aren’t as common include: gastrointestinal symptoms, new loss of smell or taste, skin changes (like lesions), confusion, and eye problems.

SOURCE: Mayo Clinic

Why does COVID-19 cause loss of smell?

Some patients can temporarily lose their sense of smell. This is because the “hook” of cells used by SARS-CoV-2 to latch onto and infect cells is up to 700 times more prevalent in the olfactory-supporting cells lining the inside of the upper part of the nose than in the cells lining the rest of the nose and windpipe that leads to the lungs. The supporting cells are necessary for the function/development of odor-sensing cells.


Why does COVID-19 cause shortness of breath?

COVID-19 can cause damage to the lungs that impedes their ability to remove oxygen from the air. A lot of patients develop what’s known as severe acute respiratory distress syndrome.

SOURCE: Jennifer Nuzzo

Does COVID-19 affect the heart?

One of the mechanisms that the SARS-CoV-2 virus uses to enter the lungs, called the ACE2 receptors, lives in the heart as well. When the virus enters the heart, it can cause clots, pulmonary embolism, or clots within the arteries of the heart causing a heart attack.

SOURCE: Public Health On Call

When and how should I seek medical attention?

Via the CDC:
If you develop any of the following emergency warning signs for COVID-19, get medical attention immediately by calling your doctor’s office. Emergency warning signs include (but are not limited to):

  • Trouble breathing
  • Persistent pain or pressure in the chest
  • New confusion or inability to arouse
  • Bluish lips or face

Please call your medical provider for any other symptoms that are severe or concerning to you.


How are coronaviruses transmitted between people?

Coronaviruses are typically transmitted from person to person through exhalation of respiratory droplets (from the nose and mouth) and close contact. People can contract COVID-19 if they breathe in droplets from an infected person who coughs or exhales droplets. Those droplets can also land on objects and surfaces, and people can then catch the virus from touching those surfaces and then touching their eyes, nose, or mouth. Coronaviruses are typically transmitted from person to person through exhalation of respiratory droplets (from the nose and mouth) and close contact. People can contract COVID-19 if they breathe in droplets from an infected person who coughs or exhales droplets. Those droplets can also land on objects and surfaces, and people can then catch the virus from touching those surfaces and then touching their eyes, nose, or mouth.

Small particles that contain infectious amounts of virus can also remain suspended in the air for a period of time and travel farther distances than larger droplets usually produced when people sneeze or cough.

Wearing a mask, staying at least six feet away from others, and avoiding prolonged contact (more than fifteen minutes) indoors with others are all helpful mitigation factors.

SOURCE: Global Health NOW and Public Health On Call Podcast

When people are asymptomatic, can they spread the virus?

Yes. A lab study suggests that as many as 50% of people who have the disease show no symptoms and are still able to spread the disease.

SOURCE: Gigi Gronvall

How long is an asymptomatic carrier shedding the virus?

Most people with COVID-19 can discontinue isolation 10 days after symptom onset. For people with no symptoms of COVID-19, isolation can be discontinued 10 days after the date of their first positive test.


If people are asymptomatic, how does the virus get from one person to another?

We’re still trying to understand how asymptomatic transmission happens and the extent to which it happens.

A few ways that we think that the virus spreads: if people are talking to each other from relatively short distances, it’s possible for someone who is infected and doesn’t yet have symptoms to put some virus out there that someone who is standing close by could be exposed to. We also know that some outbreaks have occurred in settings where people are singing. The more you force air out of your mouth, the greater possibility of carrying virus with it.

Transmission has also occurred in very close quarters, like between husbands and wives or roommates. We don’t know exactly how that transmission occurred, but you can imagine any number of ways: if people are touching their mouths and then touching surfaces or something along those lines.

There’s a lot of work that still needs to be done to understand the extent to which asymptomatic transmission happens and how exactly it does.

SOURCE: Jennifer Nuzzo

Is COVID-19 airborne?

New evidence points towards likelihood that the virus may be spread through aerosols that linger, not just droplets that fall.

Droplets caused by coughing and sneezing are still the main source of infection. Remaining six feet away from others means you are less likely to be exposed to droplets.

There can also be fomites, which is infectious material from droplets or aerosols that land on surfaces you might touch. Handwashing is very effective in this circumstance.

SOURCE: Public Health On Call Podcast

What is known about young children and whether they are carriers and can transmit the virus?

Young children can be infected. In general, though, children are not falling ill as frequently as older adults are.

There is a rare and dangerous condition in sick children called multi-system inflammatory syndrome in children (MIS-C) which is thought to be caused by an immune reaction to SARS-CoV-2.

SOURCE: Public Health On Call Podcast

Of those infected, what percentage will require hospitalization? And what percentage will require care in an intensive care unit (ICU)?

Hospitalization rates vary by age group and increase with age. Approximately 90% of hospitalized patients have one or more underlying conditions, the most common being obesity, hypertension, chronic lung disease, diabetes, and cardiovascular disease.


Are there different “species” of coronavirus like there are for Ebola?

Among the thousands of samples of the long strand of RNA that makes up the coronavirus, 11 mutations have become fairly common. But as far as we know, it’s the same virus infecting people all over the world, meaning that only one “strain” of the virus exists.

SOURCE: Peter Thielen, Johns Hopkins Applied Physics Laboratory

Is COVID-19 worse than the flu?

Yes. COVID-19 is much deadlier than the flu—the virus kills about one in 200 infected people. Seasonal flu kills about one in 1,000 infected people.

SOURCE: Crystal Watson

What does “recovered” mean?

The CDC advises:

You can be around others after:

  • 10 days since symptoms first appeared AND
  • 24 hours with no fever without the use of fever-reducing medications AND
  • Other symptoms of COVID-19 are improving*

*Loss of taste and smell may persist for weeks or months after recover and need not delay the end of isolation.


What is the possibility of reinfection after you have recovered from COVID-19?

We do not yet know if people with antibodies to SARS-CoV-2 are immune and, if they are, how long any protection might last.

The CDC advises:

Data to date show that a person who has had and recovered from COVID-19 may have low levels of virus in their bodies for up to three months after diagnosis. This means that if the person who has recovered from COVID-19 is retested within three months of initial infection, they may continue to have a positive test result, even though they are not spreading COVID-19.

CDC recommends that all people, whether or not they have had COVID-19, take steps to prevent getting and spreading COVID-19. Wash hands regularly, stay at least six feet away from others whenever possible, and wear masks.


Is there evidence of a heightened risk to pregnant women?

Pregnant people might be at an increased risk for severe illness. There may be an increased risk of adverse pregnancy outcomes, such as preterm birth, among pregnant people with COVID-19. Limited evidence suggests that it is not likely for mothers with COVID-19 to spread the virus to babies in their breast milk, but there are precautions mothers with COVID-19 should take if they are breastfeeding. Please visit the CDC resource for precautions pregnant and breastfeeding people can take to reduce these risks.


What is known about how this virus responds to warm weather and the potential for “seasonality?”

Certain viruses, like influenza, tend to have a seasonality. Some people think it’s humidity. Some people think it’s temperature. Some people think its behavioral, and which of those is most important is not known. One potential concern is that if we are indoors more often and more likely to cough on each other, we could see more in-household transmission.

SOURCE: Jennifer Nuzzo
RELATED: COVID-19: Immunity and Seasonality

Are COVID toes related to blood clotting?

Yes. People with coronavirus have the ability to form clots more easily, and one place you can get clots is in the small vessels that supply blood to your toes. That’s what’s responsible for the purple toes you are seeing—the discoloration is because they are being deprived of blood flow.

SOURCE: Amesh Adalja

What makes this upper respiratory infection caused by an RNA virus any different from hundreds of other upper respiratory infections caused by RNA viruses?

There are two key differences: First, it’s causing severe disease for individuals which causes big strains on the healthcare system.

Second, we just don’t know much about it compared to other RNA viruses that cause upper respiratory infections every day.

SOURCE: Lauren Sauer


Are some groups at a higher risk for severe COVID-19 illness?

Available information suggests that the following are at a higher risk for severe illness from the virus:

  • People of any age with the following conditions:
    • Cancer
    • Chronic kidney disease
    • COPD
    • Immunocompromised state from solid organ transplant
    • Obesity (BMI of 30 or higher)
    • Serious heart conditions, such as heart failure, coronary artery disease, or cardiomyopathies
    • Sickle cell disease
    • Type 2 diabetes mellitus

As you get older, your risk for severe illness increases. For example, people in their 50s are at higher risk for severe illness than people in their 40s. Similarly, people in their 60s or 70s are, in general, at higher risk for severe illness than people in their 50s. The greatest risk for severe illness is among those aged 85 or older.

Other people who may need extra precautions include: racial and ethnic minority groups, people in rural communities, people with disabilities, pregnant and breastfeeding people, people experiencing homelessness, and people with developmental and behavioral disorders. For a full list and recommended precautions, please visit the CDC resource.


Do higher-risk patients ever have mild coronavirus, or is it always the case that people who are at higher risk get very sick?

They do. Certainly, people of advanced age and people with underlying conditions statistically are among those mostly likely to be hospitalized and die, but that’s not always the case. People in both of those categories also may have mild infection or may become sick and survive their illness.

SOURCE: Jennifer Nuzzo

Are there options for supporting seniors who don’t have online access for getting groceries delivered?  

Look for ways to identify at-risk people and get groceries delivered to their homes. If they have to go out, they should be social distancing in the grocery store and practicing hygiene. The handles on shopping carts, for example, are potentially a source of infection even if the store is empty. 

SOURCE: Joshua Sharfstein

Should people on immunosuppressive drugs stop taking their medications? 

They should talk to their doctors. There are different kinds of drugs, and people are on them for different reasons. Some doctors may think the risk/benefits suggest they should stop, and some will say to continue the medication.

SOURCE: Tom Inglesby

How is COVID-19 impacting people without spleens? (With certain bacterial diseases, people without spleens can get very severe infections.)

There is not specific data around this. In general, we think of people who do not have a spleen or whose spleen is not functioning well as being immunosuppressed. I would be more cautious with those individuals and more aggressive in their care. Those individuals would want to have more social distancing than the average person.

SOURCE: Amesh Adalja

Are women taking oral contraceptives more at risk from blood clotting from COVID-19?

There is an elevated risk of clotting from oral contraceptives. COVID will synergize with whatever other propensity you have to get clots so someone on birth control may be more likely to clot than the average person.

This is something we need more guidance around—if women who are on birth control pills get sick, should they consider stopping the medication and using an alternative method of birth control during that period of time?

SOURCE: Amesh Adalja


When is testing important?

Testing is particularly important for people who are seriously ill. Knowing the diagnosis is important for clinical care because it allows health care workers to protect themselves, and is necessary for research into treatments.

For people who are mildly or moderately ill, testing can help assure that they isolate themselves and alert people they have come in contact with of the potential need for quarantine. By quickly identifying individuals who are sick and isolating them, public health authorities can reduce the spread of the novel coronavirus.

In many cases, people who have been exposed to the coronavirus should be tested, to inform additional contact tracing efforts.

To assure both that tests are available for those who need them and that health professionals are prepared to do the test safely, adequate safety equipment is essential. Not every clinic or medical office will conduct the testing. Physicians and public health authorities should direct people to where they can be tested.

SOURCE: Tom Inglesby

What does testing tell us the spread of the virus? What is “percent positive”?

Public health officials rely on testing results to track the state of the pandemic and policymakers use this information to guide decisions on reopening schools and businesses.

Percent positive is the percentage of all coronavirus tests performed that are actually positive, or: (positive tests)/(total tests) x 100%. The percent positive (sometimes called the percent positive rate or positivity rate) helps public officials understand the current level of SARS-CoV-2 transmission in the community and whether or not a community is doing enough testing for the number of people who are getting infected.

SOURCE: David Dowdy and Gypsyamber D’Souza

Why aren’t there enough tests available and will this change?

Earlier in the pandemic, the issues were collection devices—not enough swabs or viral transport media (the fluid that the swab goes in).

Now, the issues are a bit different. The testing process is a very complex system. There are point- of-care tests, which are rapid. And then high-throughput diagnostic tests, which are PCR tests— the ones traditionally done in hospitals, clinical labs, commercial labs, and public health labs. Both those tests are in short supply. Pipette tips—plastic components for test cartridges—are also in short supply.

There’s huge demand from hotspot states and people who want to get tested—so they can go see their relatives or travel, for example. This has been a challenge because we want to make sure we’re using testing for the right reasons and right purposes.

How do we get out of this? One really good answer is we all need to wear masks, distance, and follow the general rules of hygiene. If we do that, we can bring the curve back down. The curve we speak of is about ICU beds and hospitalizations, but it’s actually also about test capacity. We will be able to test as many people as we need to test if we don’t have so much transmission. We are not going to be able to massively ramp up production.

SOURCE: Public Health On Call podcast

Can the COVID-19 test tell the difference between someone with an active infection and someone who was infected in the past?

There are two different types of tests: diagnostic tests and serologic—or antibody—tests. Diagnostic tests detect active infection. Serologic tests look for the presence of COVID-19 antibodies in your blood several weeks after recovery. 

SOURCE: U.S. Food & Drug Administration

If you are tested and the test is negative, do you still have to be quarantined?

Yes. Someone exposed to a person with COVID-19 needs a 14-day quarantine regardless of test results. This is because COVID-19 can develop between two and 14 days after an exposure. 

SOURCE: Joshua Sharfstein

Are false negatives a problem with COVID tests?

A false negative would mean that you actually have the disease but you get a negative test result. It’s a falsely negative test that should have been positive.

There are some concerns about the sensitivity of SARS-CoV-2 diagnostic tests, or the swab tests commonly used in clinical settings.

If a person has had a known exposure to COVID-19 (the CDC defines “exposure” as close contact with someone who has COVID-19), but a negative COVID-19 test, that person should still quarantine and self-monitor for symptoms for 14 days after exposure.

If a person has not had any known exposure to COVID-19 and is not experiencing symptoms, there is no need to quarantine if a test is negative.

If symptoms are present but a person has a negative COVID-19 test, that person should still follow home isolation recommendations. In a clinical setting, doctors and nurses may proceed with precautions as though it is a positive diagnosis.

SOURCE: Tom Inglesby

Can a COVID test read negative if it takes too long to process the sample?

This has not happened with PCR tests. Antigen tests, or those that look for antibodies, could potentially read positive falsely if they are not processed in a certain period of time.

SOURCE: Crystal Watson

Why isn’t the value of contact tracing being realized in the U.S.?

Right now, there’s so much virus circulating in our populations that it’s hard for contact tracers to keep up. We have to bring down the number of cases so we can meet that number with the contact tracing capacity that we have.

We also haven’t invested uniformly in contact tracing and building our workforce across the country. We’ve called for about 100,000 contact tracers—there are currently about 30,000 working across the country.

SOURCE: Crystal Watson

Prevention and Infection Control

How can I protect myself against coronaviruses?

The CDC recommends the following:

  • Regularly and thoroughly wash your hands with soap and water for at least 20 seconds or clean them with a 60% alcohol-based hand sanitizer. Avoid touching your eyes, nose, and mouth with unwashed hands.
  • Maintain at least six feet of distance between yourself and anyone who doesn’t live in your household. If someone in your home is sick, maintain six feet of distance from the sick person if possible.
  • Cover your mouth and nose with a mask when around others.
  • Cover your mouth and nose with your bent elbow or a tissue when you cough or sneeze, then dispose of the used tissue immediately.
  • Clean and disinfect frequently touched surfaces daily, including doorknobs, tables, light switches, countertops, handles, desks, phones, keyboards, toilets, faucets, and sinks.
  • Stay home if you feel unwell. If you have a cough, fever, and difficulty breathing, call your health provider.

There is growing evidence that wearing masks protects the wearer as well as others.


Does wearing a mask protect me from getting sick?

There is growing evidence that wearing masks protects the wearer as well as others.

Masks—no matter what kind of mask—filter out the majority of viral particles.

SOURCE: Public Health On Call

Are gloves recommended?

Gloves are important in a clinical setting but not needed out and about in everyday life. The most important thing you can do to prevent infection is to wash your hands when you touch surfaces.

SOURCE: Jennifer Nuzzo

Is hand sanitizer effective to protect against COVID-19?

If soap and water are not readily available, use a hand sanitizer that contains at least 60% alcohol. Cover all surfaces of your hands and rub them together until they feel dry.


How long does COVID-19 stay on your clothes?

The coronavirus may remain detectable for hours to days on surfaces made from a variety of materials, including clothing.

SOURCE: Joshua Sharfstein (via City Leadership Initiative)

Cleaning produce brought home from the grocery store: Should you do anything differently or use any particular cleaning products?

Here is general guidance on fruits and vegetables: (via CDC). There is not specific guidance for coronavirus. In general, the risk of transmission is low, but will be reduced further with cooking.

SOURCE: Joshua Sharfstein

Is takeout food safe? What precautions should people take?

In general, takeout food is low risk—particularly if the food is cooked. You should wash your hands after touching the packages, but the risk of contracting coronavirus from food delivery, takeout, groceries, or mail, is low.

SOURCE: Joshua Sharfstein (via City Leadership Initiative)

Is the public water supply safe from COVID-19?

There is no evidence of transmission through the public water supply.

SOURCE: Joshua Sharfstein

If two people are positive, can they quarantine together or do they have to be separated?

This is a bit of a trick question: They can be isolated together as long as we’re sure they’re both positive. There’s no problem in having multiple people isolate together. But, ideally, people should quarantine separately.

It’s also important to distinguish between isolation and quarantine: isolation is for people who are sick. Quarantine separates and restricts the movement of people who may have been exposed to the virus.

SOURCE: Eric Toner

What should you do if someone in your household is sick?

If someone in your household is sick, that person should be isolated as much as possible from other household members and all members of the household should follow guidance for quarantining.

SOURCE: COVID-19 Infection Control in Your Home 

Should the general public cover their faces with bandanas or other makeshift masks?

The CDC recommends that people wear masks in public to reduce the risk of asymptomatic spread. Masks should be worn indoors at all times, and outdoors when it is not possible to remain at least six feet away from others.

Surgical masks and homemade cloth masks can help reduce the spread of droplets.

SOURCE: Joshua Sharfstein

How should I help a friend, neighbor, or family member who is ill?

If they are ill from coronavirus, you can drop off food or other supplies for them, call them, and make sure they’re coping well. If they are getting sicker, you can help them notify their doctor or local public health agency to arrange for medical care.

SOURCE: Tom Inglesby

Are my pets at risk of getting sick?

Keep your pets—just keep your distance if you have COVID-19.

While few pet animals have been shown to carry SARS-CoV-2, and even fewer have gotten sick, it is possible for owners to transmit the COVID-19 virus to their pets. Cats and ferrets may be more likely than other kinds of pets to contract the virus. Some dogs have tested positive too.

The recommendation right now is to keep your distance from pets if you are diagnosed with COVID-19 or have been exposed to someone who tested positive. If you have COVID-19 and your pet is sick, please contact your veterinarian.

SOURCE: Meghan Davis

Is it better to go to the same grocery store several times a week for 15-20 minutes each time, or just once for an hour?

The most important thing when going grocery shopping is for you to take precautions to not be within six feet of someone else for more than 15 minutes, to wear a mask, and to wash your hands after you’ve touched any surfaces. It matters less whether you were there for 15 minutes versus an hour. It’s more about the actions and the physical distancing that you take when you're at the store. It’s also better to go when there are fewer people around.

SOURCE: Crystal Watson

Does a person’s blood type affect how infectious or sick that person may become?

There is some emerging data on blood types influencing how severely ill you might get. Blood type O seems to be more protective against severe disease, but this is correlation, not causation, so there would need to be more studies to know definitively

SOURCE: Amesh Adalja

Can you get COVID-19 from second-hand smoke?

If someone is smoking a cigarette and coughing at the same time, maybe, but there’s not a biological mechanism for how the virus would be in the smoke.

SOURCE: Amesh Adalja

Does prone body position help very severely ill coronavirus patients in the intensive care unit?

There are reports that this can be helpful and there are more proning studies going on. The challenge with proning is that it is staffing intensive. You need a lot of staff to put people in the proning position and keep them that way—and a lot of PPE to do this safely.

SOURCE: Lauren Sauer

Wet markets in China are widely believed to be a source of new infections, including coronavirus. Should they be shut down?

Wet markets have come up in a number of contexts—certainly with COVID-19, and the 2003 SARS epidemic was linked to a wet market. The challenge with COVID-19 is that we don’t actually know much about the wet market that was involved. We know that the initial cluster of patients seen by clinicians had an occupational connection there. But we don’t fully know if and how they became infected at the wet market. It’s possible that the virus was circulating in the population and somebody who had it spread it at the wet market. We don’t know that it came from the animals there.

Wet markets have been identified as places of risk for the potential of animal viruses to spill over into human viruses, and there’s an active conversation around what to do about that. Some want to shut them down but worry it will just drive the practice underground in a way that authorities are unable to regulate. Others advocate for more regulatory approaches, so that when they occur, they occur as cleanly as possible.

SOURCE: Jennifer Nuzzo


Can people expect to be immune once they’ve had the virus?

There is growing evidence that infection can confer some level of immunity. If SARS-CoV-2 is like other coronaviruses that currently infect humans, we can expect that people who get infected will be immune for months to years, but probably not their entire lives.

SOURCE: Gypsyamber D’Souza and David Dowdy

Is it possible that some people may be exposed and have mild illness but still produce antibodies that could prevent them from getting a more serious infection?

What we know from virology and from animal models is that the less virus you take in—what’s called the inoculum, or the dose—the less likely you are to get sick. We have done this in hamster models. The more SARS-CoV-2 that you give to hamsters, the more sick they get. If you give them less, they get less sick.

In the last month, there is data that even asymptomatic infection does seem to trigger immunity. There are two arms in the immune response: antibodies and T-cells. Antibody response can wane over time, but T-cells are what gives you lasting immunity. Asymptomatic—or mild—infection can give you strong T-cell immunity, which can last for a very long time.

SOURCE: Public Health On Call Podcast

Treatments and Vaccines

What treatments are there for coronaviruses?

The New York Times Coronavirus Drug and Treatment Tracker is following 21 treatments for effectiveness and safety. This resource is updated frequently.

The Novel Coronavirus Research Compendium (NCRC) is a literature curation effort by over 50 faculty members with collaborating institutions that review thousands of papers about COVID-19 research, including treatment, each week.

SOURCE: Johns Hopkins Bloomberg School of Public Health

What progress is being made on therapies or treatments for COVID-19?

There are many studies underway.

One example is convalescent serum, meaning the antibodies made by people who have already recovered from COVID-19. It’s possible that giving these antibodies to people at high risk for exposure (like household contacts or health care workers), or to people early in infection, will be beneficial.

So far, 35,000 people have been treated in the U.S. via the Convalescent Plasma Project. Johns Hopkins recently received $35 million in funding from the Department of Defense for COVID-19 blood plasma trials.

SOURCE: Arturo Casadevall

How close are we to a COVID-19 vaccine?

There are some very encouraging developments. We have a few vaccines now that will go into Phase Three clinical trials, also known as efficacy trials. That means that those vaccines have passed certain goalposts in terms of initial evaluations of safety and immune response, such that they can be evaluated in larger trials.

We know that these vaccines are promising, but we don’t yet know if they are going to work. That’s what the purpose of an efficacy trial is—as well as to provide a broader assessment of safety of the vaccine in a large number of people.

SOURCE: Ruth Karron

Will an MMR booster provide protection from COVID-19?

There is no evidence that an MMR booster will provide any protection from SARS-CoV-2. But, it is still important for people, and kids in particular, to get the MMR vaccine to prevent those diseases.

SOURCE: Crystal Watson

Is there evidence for using hydroxychloroquine as a treatment for COVID-19?

Early questions about whether hydroxychloroquine might be of help to patients with COVID-19 have been addressed by high-quality research, and the results do not support the medication’s use. In June, the U.S. Food and Drug Administration found “no benefit for decreasing the likelihood of death or speeding recovery,” and revoked the medication’s authorization for use in COVID-19.

SOURCE: Joshua Sharfstein

Is it a good idea to get a flu shot?

We’re expecting to have an increase in COVID cases this fall and winter at the same time that influenza occurs annually. It will be important to increase the proportion of the population vaccinated against flu as a means to protect ourselves and our communities, but also to save hospital capacity to treat those with COVID-19.

SOURCE: Public Health On Call podcast

The flu vaccine isn’t 100% effective; some years it may be 25%, 50%, or 75% effective. Will a vaccine for COVID-19 be more effective than the usual flu vaccine?

Regarding flu vaccine effectiveness: There are many different influenza viruses. The vaccines we get in the United States tend to protect us against three or four different kinds, but there isn’t always a perfect match between the vaccine and the viruses circulating in the community. The good news is that even if you got sick after getting the flu vaccine, odds are that you got less sick and had a shorter duration of illness because you got that flu vaccine. Flu vaccines are very good at reducing the chances of having a very severe illness and having a bad outcome requiring hospitalization or potentially leading to death. (Public Health On Call podcast, July 28, 2020)

Regarding COVID-19 vaccine effectiveness: The short answer is that we don’t yet know. The very first people who got the very first vaccine were immunized in March and it’s only July. So we don’t know very much about the durability of the immune response in people. Our hope would be [that protection would last] at least a year or more, and then people might need boosters.

SOURCE: Ruth Karron

We have a new flu vaccine every year with a new strain. Why is it so hard to get a coronavirus vaccine?

We use the same flu vaccine strategy every year that’s been developed over many decades. We know the dose of antigen—the protein—required to cause immunity, and we know basically how to swap in and out the latest strain to use the same system.

We don’t know yet what system will be used to create a COVID vaccine or what vaccine candidates will be safe and not cause side effects. We don’t know what will cause the right level of immunity. We are starting from scratch and have a lot to learn.

SOURCE: Tom Inglesby

Is interferon Alfa 2B an effective treatment? Should we be encouraging our medical community to obtain this?

There are over 30 treatments currently being tested around the world. Interferon Alfa 2B has historically been used to treat diseases such as dengue fever, HIV, and hepatitis. However, no treatments have been demonstrated to be safe and effective in high-quality studies. This treatment, like others, is considered experimental for COVID-19 at this time.

SOURCE: Joshua Sharfstein

What are randomized control trials?

A randomized control trial is a study design where a patient is randomized to either option one or option two, sometimes multiple options, and sometimes one of those options is a placebo. That study design allows us to control for factors that may influence our ability to see the benefits and the risks associated with something like a treatment.

It’s really important in this setting because we don’t know much about COVID-19. The design is how we identify medical countermeasures, vaccines, medications.

SOURCE: Lauren Sauer

Social Distancing and Other Public Health Measures

Why is the world’s response to COVID-19 so much greater than the response to other outbreaks like H1N1 or SARS?

One reason is that this virus is more easily transmitted than SARS (SARS caused an epidemic in 2003.). People with SARS were most likely to transmit the virus when they were quite ill, so a lot of transmission occurred in health care environments. Once we were able to improve infection control in health care environments, we were able to bring the epidemic under control. The 2009 pandemic caused by the new flu strain H1N1 was similar to COVID-19 in the sense that people transmitted their infections quite easily. But it was a milder virus; it didn’t produce the same level of severe illness or death that we so far have seen with this novel coronavirus.

COVID-19 is not as deadly as SARS was. On average, SARS killed about 10% of the known cases, and the estimates for this virus are much lower. But the fact that it’s so easily transmissible— much more like a flu than SARS—has made response to this pandemic quite difficult.

SOURCE: Jennifer Nuzzo

What metrics should communities be looking at to understand the real-time spread and anticipate the timing of the surge?

What’s going on at your local level can change over time, from week to week, or month to month.

Local or state health department websites can tell you what’s going on in your community. First, look at the number of COVID-19 cases. This number includes those who test positive—and, remember that not everyone who is infected or feels sick will access a test, so that number is just the tip of the iceberg. You want to see what that number of cases is doing over time, note if it is going up or down. Another thing to be aware of if there is major change is the amount of testing that’s going on in your community.

The second number to look at is the number of deaths in the community. There’s been a lot of debate about how to measure COVID-19 deaths, but you’re going to be looking at that trend over time. Not just how many people died today, but over the last week. Hopefully, it is decreasing, signaling lower risk.

This is a live public health moment. Things are changing all the time and no data is perfect, but a lot of data can be really helpful.

The Johns Hopkins Coronavirus map is a good resource to examine the spread in other states and countries around the world. The map is updated in real time as additional information is made available from a variety of sources.

SOURCE: Public Health On Call Podcast

For businesses that remain open, what are best practices to protect employees and customers?

The Center for Health Security has an Operational Toolkit for Businesses Considering Reopening or Expanding Operations in COVID-19. The toolkit includes an instruction manual, business risk worksheet, and an assessment calculator.

SOURCE: The Center for Health Security

Is COVID-19 less risky for youths and children?

Many young people have mild or even no symptoms. But every single person should think of themselves as a bridge to someone who is more vulnerable, and the way to protect those who are at high risk is to keep ourselves from getting sick. Recent data suggest that children are infected at similar rates to adults, and that children over the age of 10 transmit the virus about as efficiently as adults.

There are also still a lot of unknowns around why and how younger people can wind up with severe COVID-19 infections. COVID-19-related multi-system inflammatory syndrome in children (MIS-C) seems to affect slightly older children between 6 and 15, and can result in heart dysfunction.

SOURCE: Crystal Watson

Is temperature monitoring effective?

Taking temperatures is a very insensitive and imprecise tool. People can have elevated temperatures for all sorts of reasons that don’t correlate with illness, such as exercise. People can also suppress their fevers by taking Tylenol or other over-the-counter medications.

Having ubiquitous temperature monitors is not likely to be a great benefit and may result in a huge number of false positives and false negatives.

SOURCE: Eric Toner

What are the best ways to do contact tracing?

A great resource on contact tracing is the Johns Hopkins COVID-19 contact tracing course, which is available for free on Coursera. (If you have taken the course, check out this resource of Frequently Asked Questions about contact tracing jobs and opportunities.)

In the U.S., the commitment to contact tracing programs, to getting them to the scale and speed that we need, has really varied by state and by jurisdiction. It’s clear across the U.S. right now that very few places that have the programs, the interventions in place, to keep transmission under control. Contact tracing has to be part of that. But there are other interventions to reduce the number of contacts that people have every day to go along with it.

Contact tracing can only work if you can find cases, and we are still not there with testing in the U.S.

SOURCE: Emily Gurley

Are there effective contact tracing apps or tech platforms?

Contact tracing is critical to managing transmission, but it’s resource intensive and requires a lot of data gathering. This can strain public health departments and areas that can’t recruit or train tracers.

Digital tools can facilitate quick and effective communication and give access to real-time information. Contact tracing tools and apps can follow up with patients, notify individuals of potential exposure, and refer them to testing facilities and care if they develop symptoms. There are also apps that collect user-generated data where users report symptoms or fill out surveys that can help officials map outbreaks.

But these tools may be costly, and there are questions of usability of the platforms. There are also privacy considerations, as some apps require the use of Bluetooth and location sharing.

SOURCE: Smisha Argawal


How long will social distancing measures need to be in place?

I don’t think things will be completely back to normal until we have a vaccine, especially for things like mass gatherings. There is a cost to keeping everything closed down—and not just an economic cost, but peoples’ health. There is a psychological impact of being locked up and not being able to live your life that really has to be measured.

Everybody wants to get back to normal, but it’s going to take a little bit of time and it has to be done in a really measured and mindful way.Everybody wants to get back to normal, but it’s going to take a little bit of time and it has to be done in a really measured and mindful way. 

SOURCE: Amesh Adalja
RELATED: National Coronavirus Response: A Roadmap to Reopening

How should we be thinking about schools reopening?

The biggest factor determining risk in schools is what the virus is doing outside of them. In places where you have a very high test positivity, like well into the double digits, that suggests that the outbreak is very widespread and that testing isn't keeping up.

Regardless of whether schools open online, in person, or with a hybrid approach, there will be learning disruptions to consider. COVID-19 is exacerbating growing inequities around achievement, development, and graduation rates.

Schools can also expect a year of uncertainty and should think about plans for positive cases among students, faculty, and staff, or spikes in community transmission. Teachers and parents will need to help children manage distress caused by uncertainty, distance learning, and fear, and school leaders and educators will need to plan for different scenarios.

SOURCE: Johns Hopkins Bloomberg School of Public Health

How should schools prioritize testing?

There are a lot of visions of using testing as a way to establish safety but that’s not a clear-cut endeavor, particularly when you test people who don’t have clinical symptoms. Schools need to consider how quickly they can get tests back and if the results will meaningfully change interventions. Regardless of how we use tests, we still need to maintain safety protocols—distancing, masks, and other things—because no test is perfect and there will be incorrect answers generated by these tests.

SOURCE: Jennifer Nuzzo


What are the disparities in testing for marginalized communities and how can we address them?

We’ve largely built testing off our health care system, with all the inequities built into it. That’s one of the reasons we’re suggesting a call center that’s available to everyone. Even though this virus started in the United States with people returning from cruises or international travel, the populations at greatest risk are low-income minority communities with high rates of chronic illness and insecure housing and food. The initial attention to people who got coronavirus on cruises and international trips has distracted us from the urgency of providing not just testing, but also follow-up services—food, housing, and other supports—for vulnerable populations. It’s the right thing to do as a matter of justice, but it’s also absolutely critical for control of the disease.

SOURCE: Joshua Sharfstein
RELATED: How Health Disparities Are Shaping the Impact of COVID-19

How should we think about the need for racial and ethnic diversity in clinical trials for COVID-19 vaccines?

It’s critically important that we have racial and ethnic diversity.

We know that COVID causes increased rates of severe disease in Latinx and Black populations and in Native American populations. We will certainly want to be able to offer these COVID vaccines to these high-risk populations and encourage their use. But we need to know how well these vaccines work in these populations—if different vaccines work differently—so that we can offer the most effective vaccines.

SOURCE: Ruth Karron

Why are Black and other communities of Color being hit especially hard by COVID-19?

Before COVID-19, minority communities were already disproportionately impacted by health inequities. People in those communities already have higher rates of obesity, diabetes, heart disease, and lung disease, so these are the folks who were actually going to be at more risk of getting seriously ill with COVID-19. These health inequities result from the financial stresses of being poor and the social stresses of being from a marginalized group with a history of institutionalized, sanctioned mistreatment by law enforcement and other societal institutions.

There’s a confluence of all these different factors—not having access to food, not having access to good quality housing, being crowded in small houses where there are multiple generations and unable to engage in social distancing or stock up on groceries for several weeks at a time, having to use public transportation, to work in essential jobs, and having less access to health care. These are all manifestations of structural racism.

SOURCE: Lisa Cooper

What can be done right now to reduce the toll of COVID-19 on Black and minority communities?

Keeping an eye on the data is an important priority: knowing who is impacted and where they’re impacted.

Communication is also really important—making sure that the public understands why we might be seeing these patterns, and that it’s more about our society and the way our resources and opportunities are allocated than it is about individual behaviors. We need to do what we can to better understand the challenges of those communities, engage with trusted leaders, listen with respect, and show empathy and concern. We need to recognize the remarkable contributions of African American communities and follow our words up with real actions that bring about positive change.

We also need to focus on frontline workers and low-wage workers, and understand their needs—providing protective equipment, safe spaces to work, paid sick leave, hazard pay, or health insurance and access to testing and care. And, we need to provide for people’s basic needs: stable housing, food security, and digital access to education and health care.

SOURCE: Lisa Cooper


What are good sources of information?

Are there books for people to learn more about the public health response to similar situations?

The Public Health Crisis Survival Guide is for anyone involved in a public health operational role who may have to think about how to manage a crisis and maintain credibility in the face of uncertainty. D.A. Henderson’s Smallpox, the Death of a Disease has great information about operational challenges to confronting the spread of disease and the goal of trying to reduce its impacts on society.

SOURCE: Jennifer Nuzzo

How can I learn more from experts? 

The Johns Hopkins Bloomberg School of Public Health hosts a daily podcast called Public Health On Call, featuring interviews with experts and others on the front lines.