COVID-19 (coronavirus disease 2019) May 2020 updates
These news stories have not been updated since the dates shown. Information contained in this post is here for reference only. Please see MIT Medical's most recent post for up-to-date information for the MIT community about COVID-19. (Coronavirus Disease 2019).
- May 26: Does social distancing harm one's immune system?
- May 19: Can a baby become infected during pregnancy or childbirth?
- May 13: Recovered and symptom-free, but am I still contagious?
- May 11: Can we become infected from handling home deliveries?
May 28: MIT Medical answers your COVID-19 questions. Today we bring you several recent questions from our mailbag. Got a question about COVID-19? Send it to us at email@example.com, and we’ll do our best to provide an answer.
Is it helpful or totally irrational to hold your breath when you are walking past someone?
In all likelihood, it’s not at all helpful. On the other hand, “totally irrational” seems a bit harsh for something many of us probably find ourselves unconsciously doing. In any case, the totally rational reality is that viral particles disperse quickly in air, and the turbulence caused by two people moving past each other only hastens that process. In addition, we know that length of exposure is a major factor in virus transmission. Fleeting encounters — even relatively close fleeting encounters — carry very little risk, particularly if both individuals are wearing masks.
Could the “ventilators” used for sleep apnea, such as CPAP, be useful for someone with COVID-19 who has difficulty breathing?
Unfortunately, no. Clinicians initially considered the use of CPAP (continuous positive air pressure) machines for COVID-19 patients with relatively mild breathing problems. However, it turns out that these types of breathing machines have the potential to increase the spread of COVID-19 infection by sending viral particles into the air. In fact, this very scenario is thought to have contributed to the spread of the virus in the Kirkland, Washington, nursing home that became ground zero for the illness in early March. Following protocol, first responders initially used positive airway pressure machines to treat residents with breathing problems. Of course, this was before anyone knew that the patients’ breathing problems were a result of infections with the SARS-CoV-2 virus. Thirty-five residents ultimately died of complications of COVID-19; 47 staff members were sickened.
Now that the weather is warming up considerably, is there any research on whether wearing shorts or short-sleeved shirts increases one’s risk of contracting COVID-19 if exposed? Are we safer in pants and long-sleeved shirts?
We can’t find any research specific to that question, but we already know enough about how the virus spreads to tell you that the amount of clothing you are wearing has no effect on your chances of contracting the virus. That’s because SARS-CoV-2, the virus that causes the COVID-19 illness, is a respiratory virus, and, like other respiratory viruses, it enters your body through your mucus membranes — your mouth, your nose, and (possibly) your eyes.
Theoretically speaking, wearing short sleeves or shorts might mean that you end up with some viral particles on your skin that would otherwise end up on your clothing. But just getting the virus on your skin won’t make you sick; to become infected, you’d have to get that contaminated area of skin into contact with your mucus membranes, which, as long as you keep your knees away from your nose, is pretty unlikely. So, get outside and enjoy some of this beautiful weather. Dress for comfort, but if you’re not sure you’ll be able to maintain social distance at all times, make sure your ensemble includes a mask.
May 27: MIT Medical answers your COVID-19 questions. Got a question about COVID-19? Send it to us at firstname.lastname@example.org, and we’ll do our best to provide an answer.
I read something about putting a cloth mask on a cooking-mode rice cooker to kill the virus. Is there a certain temperature where we can kill COVID-19?
According to the Centers for Disease Control and Prevention (CDC), while viruses typically survive for shorter periods in hotter temperatures, we do not yet have specific information about the temperature at which the SARS-CoV-2 virus is inactivated.
That said, when it comes to killing viruses, there’s no substitute for soap and water. The CDC recommends washing your cloth masks in the washing machine with the rest of your laundry. It can be helpful to put them inside a mesh laundry page or zippered pillowcase to keep straps and ear-loops from getting tangled up with other laundry inside the machine.
You can also hand-wash your masks in a bleach solution made up of 4 teaspoons household bleach per quart of room-temperature water. (Check the label to make sure your bleach is intended for disinfection.) Soak the face covering in the bleach solution for 5 minutes, and rinse thoroughly with cool or room-temperature water.
To machine-dry your mask, the CDC recommends using the highest heat setting and leaving it in the dryer until completely dry (and still in the mesh bag or pillowcase). If you don’t have access to a machine dryer, you can lay your mask flat to air dry, preferably in direct sunlight.
The rice cooker is a versatile kitchen appliance, indeed, but it’s not helpful when it comes to sanitizing your cloth facemasks. Save it for cooking rice and, apparently, almost anything else you might imagine — rice-cooker pineapple upside-down cake, anyone?
May 26: MIT Medical answers your COVID-19 questions. Got a question about COVID-19? Send it to us at email@example.com, and we’ll do our best to provide an answer.
I’ve been hearing people say that staying home and social distancing is harming our immune systems. The reasoning is that if we don’t come into contact with many germs, our immune systems weaken. This means that once we all start coming out of the house more, we’ll be more susceptible to colds and flu and even the new COVID-19 illness. Is this true?
We’ve been hearing this theory too, and we can assure you that this is NOT the way your immune system works.
Many people have heard of the “hygiene hypothesis” — the idea that individuals who are exposed to a variety of microbes (i.e., germs) in childhood build better immunity. In fact, there is evidence that young children who have early exposure to different types of germs are less likely to develop allergies and autoimmune disorders such as hay fever, asthma, or inflammatory bowel disease.
However, by the time you are an adult, you have already spent years being exposed to many types of bacteria and viruses. You’ve created a robust immune system that can respond to these microbes. Your immune system “remembers” viral and bacterial markers, and as soon as one of these markers shows up, your body starts making antibodies to destroy that intruder.
Of course, SARS-CoV-2, the virus that causes the COVID-19 illness, is a new virus. Before its initial appearance in humans at the end of 2019, no human had been exposed to the virus or had opportunity to build immunity against that particular pathogen. But while your immune system won’t have any specific “memory” of the virus, it will mount an immune response if you are infected — because that’s how your immune system works. Coming into contact with germs spurs an immune response, but it doesn’t do anything to make your immune system stronger. And this current period of contact with fewer germs does nothing to weaken the immune response you will be able to mount, as needed, in the future.
But that doesn’t mean social distancing will have no effect on your immune system. The psychological effects of social isolation can affect your immune system. The culprits are loneliness and stress.
Research shows that our anti-viral response is suppressed when we feel lonely. An analysis of 148 different studies involving more than 300,000 people found that people who were more socially connected were 50 percent less likely to die over a given period. One experiment even found that people with many social ties are less susceptible to the common cold.
Stress has similarly harmful effects on immune function, because the hormones involved in a stress response — cortisol, which stimulates the production of sugar, and epinephrine and norepinephrine, which increase heart rate and elevate blood pressure — interfere with the function of immune cells.
The pandemic has created different types of stress for all us, including the stress of having to socially distance ourselves for an extended period of time. So, work on staying in contact with the people you care about. Call, video chat, share photos and updates on social media, or find other ways to connect. And try to find ways to manage your stress. The Centers for Disease Control and Prevention (CDC) has some useful tips. And Community Wellness at MIT Medical offers a guided, three-minute relaxation recording at 617-253-CALM (2256) and free MP3 files you can download to practice mindfulness and relaxation on your own.
In addition to staying connected and controlling stress, other strategies for maintaining a healthy immune system include eating a balanced diet, exercising regularly, and getting enough sleep. Community Wellness at MIT Medical offers resources to help with these parts of your life as well — everything from information to virtual classes and free downloads.
While it’s unlikely that you’ll catch a cold the moment you start going out more, it will bring you into contact with more germs, and there’s a lot you can do to prepare that old immune system for those challenges. The pandemic has changed many things about our lives, but the road to good health is still paved with plenty of fruits and veggies, deep breaths, good friends, and a good night’s sleep.
May 20: MIT Medical answers your COVID-19 questions. Got a question about COVID-19? Send it to us at firstname.lastname@example.org, and we’ll do our best to provide an answer.
How long before COVID-19 symptoms appear is a person contagious? In other words, based on the day a person actually becomes ill, how far back should contact tracing go?
While the incubation period for the virus can be as long as 14 days, research suggests that people who are infected with SARS-CoV-2, the virus that causes the COVID-19 illness, may become infectious to others several days before they start to feel ill.
A study of 94 patients in China showed that viral load peaked shortly after the onset of symptoms, indicating that people may actually be more infectious in the days before they become ill and before the immune system has a chance to kick in. Another study, which looked at 77 pairs of individuals in which one person infected the other, found that contagiousness both began and peaked before the first symptoms of illness — 2.3 days and 0.7 days respectively. Those researchers concluded that about 44 percent of COVID-19 infections spread from person to person before symptom onset.
For this reason, the Centers for Disease Control and Prevention (CDC) considers contact tracing to be crucial in protecting communities from further spread of the virus. “Time is of the essence,” they state. “If communities are unable to effectively isolate patients and ensure contacts can separate themselves from others, rapid community spread of COVID-19 is likely to increase to the point that strict mitigation strategies will again be needed to contain the virus.”
The CDC’s contract-tracing protocol involves identifying and contacting close contacts of individuals who are diagnosed with COVID-19. The CDC identifies a “close contact” as “someone who was within 6 feet of an infected person for at least 15 minutes starting from 48 hours before illness onset until the time the patient is isolated.” Anyone who has been informed that they have had that level of contact with someone who has been positively diagnosed with COVID-19 should stay home, maintain social distancing, and self-monitor until 14 days from the last date of exposure to the infected individual.
May 19: MIT Medical answers your COVID-19 questions. Got a question about COVID-19? Send it to us at email@example.com, and we’ll do our best to provide an answer.
If a pregnant woman tests positive for the virus, can the fetus be affected? Is she delivers, will the newborn be infected? And how about breastfeeding — could a baby be infected by breast milk from a mother who did not know she had the virus?
Because this is a new virus, there has not been a lot of research on these questions, but, says Medical Director and Obstetrician Cecilia Stuopis, studies done thus far have not found evidence of “vertical transmission” — the medical term for when a baby acquires an infection from its mother during pregnancy or childbirth. Two relatively small studies of COVID-19-infected mothers, involving nine and 38 subjects respectively, found that none of their babies were affected by the virus or tested positive. Two case studies (see here and here) reported that infants born to infected mothers had elevated levels of antibodies to the virus but no symptoms of illness.
However, vertical transmission cannot be ruled out completely in another study where three out of 33 infants born to infected mothers showed clinical signs of infection and tested positive. However, since the newborns in this study were not tested until three days of age, it’s possible that they were infected after birth.
“In any case, we think the chances of vertical transmission are extremely low,” Stuopis says. “However, we are concerned that a mom with COVID-19 could transmit the infection to her baby after delivery through respiratory secretions. So, most labor and delivery units are now routinely testing everyone upon admission. A mother who tests positive may be separated from her baby for some period of time after delivery and, once reunited, will be asked to practice excellent hand-washing and wear a mask to minimize the baby’s exposure to her secretions.”
There have been even fewer studies looking at the question of whether COVID-19 can be transmitted to babies through breast milk, but according to the CDC, available data suggest that this mode of transmission is unlikely. Dr. Stuopis concurs. While she notes that the CDC recommends precautions for breastfeeding mothers who are infected with COVID-19 — wearing a face covering, careful hand hygiene, and use of a dedicated breast pump if pumping — she stresses that the benefits of breastfeeding far outweigh any possible risk. “For most babies, breast milk can confer significant health benefits,” she notes, “including the transmission of beneficial antibodies, so we continue to recommend that mothers either breastfeed, or pump and feed the expressed milk to their baby.”
May 13: MIT Medical answers your COVID-19 questions. Got a question about COVID-19? Send it to us at firstname.lastname@example.org, and we’ll do our best to provide an answer. Today, you get a two-for-one deal, as we answer two related questions about recovery from the virus.
Question 1: How long after symptoms occur are you still contagious? Also, if you feel better for a couple days and then “relapse,” are you still considered contagious?
There’s a lot about this virus that is still unknown and unpredictable, not the least of which is how the course of recovery may progress for any individual patient. If you contract SARS–CoV-2, the virus that causes the COVID-19 illness, we can’t tell you how sick you will get, which symptoms you will have, or how long it will take for you to fully recover. Nor can we say exactly how long you may be contagious. We’ve identified possible ranges for all of these things, but what we are most sure of is that the course of the illness varies greatly from person to person.
That said, the Centers for Disease Control and Prevention (CDC) has established minimal criteria for your return to whatever passes for “normal life” these days. If you’ve been sick with COVID-19, whether your illness was confirmed by testing or symptom-based criteria, the CDC recommends that you remain isolated for at least 10 days after your symptoms first appeared AND at least three days (72 hours) after recovery.
What does “recovery” mean? According to the CDC, it means that you’ve gone three days without a fever, and without the use of fever-reducing medications, and that your other symptoms, such as cough or shortness of breath, have shown progressive improvement or have gone away completely. In other words, if you’re fever free and improving for two days but start running a fever again or coughing more, that 72-hour countdown clock gets reset, and you’ll need to start counting down those three days again as soon as you’re once more fever free and otherwise improving.
Finally, keep in mind that these are minimal criteria. If you have the luxury of taking more time to be sure that you’ve finally, actually, really, truly recovered, you should take it. And coming out of isolation does not mean throwing caution to the wind. You should still continue taking the precautions we are all taking at this time — staying home as much as possible and, if you must go out, wearing a mask and maintaining social distance between others and yourself.
Question 2: My daughter is a nurse who was hospitalized with COVID-19 but has fully recovered. She’s been tested several times since getting out of the hospital, but she is still testing positive after being symptom free for more than two weeks. Given her test results, how confident are you in the CDC’s advice that people can stop self-isolating after being symptom free for 72 hours?
With good reason, the CDC recommends increased caution for healthcare providers returning to work after recovery from a confirmed or suspected COVID-19 illness. Some healthcare facilities follow the CDC’s symptom-based strategy outlined above — 10 days since symptom onset, three-days post-recovery. Others, perhaps including the facility where your daughter works, use the CDC’s alternative strategy, which requires two negative PCR tests administered within 24 hours.
“The phenomenon of individuals continuing to test positive for some time after they appear to have recovered is one we’ve known about for a while,” says Dr. Shawn Ferullo, MIT Medical’s chief of student health. “I’ve heard of people testing positive up to 37 days after their symptoms had completely disappeared. The test is extremely sensitive, so these are ‘true positives’ in the sense that the test truly is detecting genetic material from the virus, but the question is whether or not it is infectious viral material. Most of us now believe these individuals are not infectious, even though they continue to test positive and are being held out of work.”
The CDC appears close to reaching the same conclusion, noting that “detecting viral RNA via PCR does not necessarily mean that infectious virus is present.” While CDC research on this topic is ongoing and as yet unpublished, they note that they have been unable to culture viral specimens obtained from individuals more than nine days following the onset of symptoms. This means that these viral specimens were not capable of replicating — or, in other words, they were not infectious. In fact, the CDC’s preliminary conclusion is that “the statistically estimated likelihood of recovering replication-competent virus approaches zero by 10 days or more than three days after recovery.”
So, while your daughter may be held out of work for some time longer, you and she and can both be reassured that she is almost certainly fully recovered from the illness and no longer infectious.
May 12: MIT Medical answers your COVID-19 questions. Got a question about COVID-19? Send it to us at email@example.com, and we’ll do our best to provide an answer.
I’ve been hearing about a new “antigen test” for COVID-19. What is it, and how does it work?
The Food and Drug Administration (FDA) recently authorized the first antigen test to diagnose infection with SARS-CoV-2, the virus that causes COVID-19, which is why you’ve been hearing about it. The new test is from a company called Quidel Corp., but the FDA expects to authorize additional tests of this type in the near future.
If you or your child has ever had a rapid strep test, you’ve had firsthand experience with an antigen test. While other diagnostic tests for COVID-19, known as PCR tests, look for genetic material from the virus, the antigen test looks for molecules on the surface of the virus. PCR tests require expensive and specialized equipment and can take hours or days to get results. In contrast, antigen tests can be run in a lab or doctor’s office in about 15 minutes.
Unfortunately, there’s a trade-off between speed and accuracy, and antigen tests often fail to identify people who are actually infected, a shortcoming the FDA acknowledges. “Positive results from antigen tests are highly accurate,” the FDA writes, “but there is a higher chance of false negatives, so negative results do not rule out infection.” Just as your doctor may order a throat culture to definitively rule out strep throat when a rapid strep test comes back negative, the FDA recommends using the more sensitive COVID-19 molecular test for symptomatic individuals who test negative with antigen tests “prior to making treatment decisions or to prevent the possible spread of the virus due to a false negative.”
Some public officials anticipate using the COVID-19 antigen test as a tool for widespread screening, including the screening of asymptomatic people. Given the test’s speed and relatively low cost, the thought is that people could rapidly and easily be tested as a prerequisite to school attendance, work, or travel. But many medical experts, including Dr. Shawn Ferullo, MIT Medical’s chief of student health, see the test’s lack of sensitivity as precluding that type of use. However, he says, MIT Medical will be evaluating this test along with others, as they come on the market. “I think it is safe to say that we would use antigen testing if it is available and shows good data,” he says. “I envision it being a useful screening tool for patients who present with symptoms, the same way we use rapid strep tests or rapid flu tests. We know that all of these rapid tests miss people who are truly sick, but a positive result is almost always correct, and a more sensitive test is available as a follow-up for symptomatic patients who test negative.”
May 11: MIT Medical answers your COVID-19 questions. Got a question about COVID-19? Send it to us at firstname.lastname@example.org, and we’ll do our best to provide an answer.
Can we get the virus by handling our deliveries, which are usually packed in bags or boxes upon their arrival? We are aware that the virus lives for many hours and/or days on different surfaces but we also know that experts say that the virus is generally spread from person to person. Can you clarify?
It’s theoretically possible to pick up the virus from a surface, but you’re right that it is usually spread from one person to another. Here’s why:
Since COVID-19 is caused by a respiratory virus carried in respiratory droplets, transmitting the virus directly from one person to another is a simple, one-step process: An infected individual expels viral-laden respiratory droplets while another, nearby individual breathes them in. To try to prevent this type of transmission, we wear face coverings and try to maintain at least a six-foot distance between others and ourselves.
In contrast, becoming infected from a contaminated surface, like a recently delivered bag of groceries, requires the successful completion of a complex, multi-step process: An area of the bag becomes contaminated with a sufficiently infectious amount of virus; you come in direct contact with that contaminated area; you transfer a sufficient number of viral particles to your hands; and, finally, you use your hands to transfer that virus directly to your mucus membranes.
Let’s look at this process in a little more detail. First, to contain a sufficiently infectious number of viral particles, the bag would have to have been contaminated relatively recently. Although studies have found detectable levels of the virus remaining on surfaces for a significant amount of time, a “detectable” amount is not necessarily the same as an infectious amount. We don’t know how many viral particles are required to transmit an infection, but we do know that this virus degrades rapidly outside the body. Regardless of surface type, the half-life of the virus — the time required for half of the viral particles to die — is measured in a matter of hours, not days.
And even if your grocery bag has an infectious amount of virus on it, those particles would likely be concentrated in only one or two small areas. So, the next step requires some precision. You would need to come into direct contact with the contaminated spot, or spots, on the bag, and you would also need to pick up a sufficiently infectious amount of virus when you do.
But you can’t get sick just from getting viral particles on your hands. To contract the virus, you would then need to transfer those viral particles — again, in sufficient number — to your mucus membranes, either by touching your mouth or your nose (or maybe your eyes) with your contaminated hands.
So, yes, it may be possible to get sick this way, but it’s clear why this is not the primary way the virus is spread. And this mode of transmission is completely preventable: Just wash your hands immediately after touching any surface that has any possibility of being contaminated. Remember, you can’t get the virus just by touching it. You also have to get it from your hands to your respiratory system, and that connection is readily broken with soap and water.
May 7: What’s the difference between a diagnostic test for COVID-19 and an antibody test? How does the testing process work? How accurate are these tests? Should I be tested? Our new FAQ answers these questions and more. Still have a question about testing? Send it to us at email@example.com, and we’ll do our best to provide an answer.
May 4: In a recent post, we warned readers against rushing out to purchase one of the many COVID-19 antibody tests suddenly flooding the market, noting that few of these tests have been independently validated, and many are grossly inaccurate. But what about the tests the U.S. Food and Drug Administration (FDA) has approved for emergency use? How useful or accurate are those tests? And, if you were to take one, what might your individual result mean?
Antibody tests, or “serology tests,” are blood tests that look for signs of an immune response to infection — in this case, immune molecules, or antibodies, specifically targeted to fighting SARS-CoV-2, the virus that causes the COVID-19 illness. While we still don’t know if these COVID-19 antibodies can protect you from being infected with the virus again, their presence in the blood would indicate that you had previously been infected with the virus, even if you never had noticeable symptoms.
But when it comes to antibody testing, the bigger question is this: If you have a positive result on a SARS-CoV-2 antibody test, what is the probability that you actually had COVID-19? Strangely enough, the answer to this question has less to do with the accuracy of the test than with the number of people in the population who have actually been exposed to the virus.
For example, the FDA- and CE (European Union)-approved antibody test from Cellex promises 94% sensitivity (percentage of correctly identified true positives) and 96% specificity (percentage of correctly identified true negatives). In other words, it’s a pretty accurate test.
But let’s suppose we’re using this test on a random sample of 1,000 people from a population with a 5% prevalence rate, meaning that, on average, 50 out of 1,000 people will actually have antibodies to the virus.
Of these 50 people with antibodies, the Cellex test will correctly identify 94 percent of the true positives, or 47 individuals. When it comes to true negatives, the Cellex test will correctly identify 96 percent, or 912 out of 950 individuals; the other 38 will get a positive result, even though they do not have antibodies. The total number of positive results will be 85 out of 1,000. But only 47 of those positive results will be correct, meaning that if you are one of those 85 individuals with a positive result, the probability that you actually have SARS-CoV-2 antibodies is only 55 percent — a predictive value that is better than a coin toss, but not by much.
Want a complete explanation? Watch MIT Professor Michael J. Cima demonstrate the math that explains how a test’s sensitivity and specificity may combine with low population prevalence to make an individual antibody test relatively useless.
But while individual results on antibody tests may not be particularly useful at the moment, antibody tests still have a role to play as part of a larger, population-level surveillance strategy that can tell us where the virus has been and how it is spreading over time. When used for this purpose, individual false-positive results matter less, because those errors can be factored out. The hope is that this information can be used to help local and state governments plan for the resumption of normal activities across entire populations, rather than one person at a time.