As we continue to navigate these unprecedented times, KCBS Radio is getting the answers to your questions about the coronavirus pandemic. Every morning at 9:20 a.m. Monday-Friday we're doing an "Ask An Expert" segment with a focus on a different aspect of this situation each day, sponsored by the San Francisco Police Department.
Today we’re back to medicine and science with Dr. Bob Wachter, the chair of the UCSF Department of Medicine.
Dr. Wachter, good to talk to you again. How are you doing?
Thank you Stan, good; they're opening up the golf courses.
Hey, glimmers of hope for everything. All right. You may be able explain to me how you're supposed to play golf when the cup is an inch above the green. You never actually putt out, is that right?
I think some of them will have to see, but some of them, yes, are inverting the cup. So you actually hit the cup rather than it goes into the hole. I'm planning on giving myself any putt less than six feet to maintain distance.
You have the 10 foot rule too, I think that would make sense to stay super safe.
Well before we get into the questions - and we have a lot today - I think everybody wants to know your take on the remdesivir news of yesterday. So we had the Gilead - National Institutes of Allergy and Infectious Disease study. We also had this study from Wuhan in China. The two seem to be somewhat contradictory. How do you add all this up?
Welcome to science. This sometimes happens where two trials give you different results and you're not sure. The one conducted or run by the NIH showed what seemed to be a moderately impressive improvement in outcomes. The two main outcomes were decrease in the length of time - these were only sick people in hospitals, people who were in the hospital because they're short of breath, their oxygen level was low. And so those are the people that we worry about, that they're gonna get very sick and some of them will die. And so the two outcomes of this drug - and it's an IV-only drug, it’s not a drug you can take at home or take to prevent the infection.
And so the two outcomes were the length of time that it took to leave the hospital was shortened from 15 days to 11 days, about 30%. And the mortality rate went from about 11% to, I think, about 8.5% - also about a 20% drop. And so those are meaningful. They're not game changing, but they're meaningful. And if I was sick enough to be in the hospital today with COVID, I would want to receive it.
The other trial from China showed no difference at all. And so we're left with still some uncertainty. There are other trials going on, and I think we'll have better information soon. But I think based on the U.S. trial and the strength of the evidence in the U.S. trial, I think you'd have to say that if you were sick enough to be in the hospital today, you would want to get it.
Another one I want to touch base with you on: we talked with the folks at UC Davis Medical Center earlier this morning, they're doing - as are several other medical facilities - plasma transfusion. So you're taking plasma from people who have had a positive COVID test and have in theory made it through the disease and then transfusing that into people who are sick. How does that work?
Yeah, in some ways, it's the oldest trick in the epidemic book. It was learned from smallpox, where people used to take the little scrapings of the lesions from people with the disease and put it on themselves to try to use the antibodies from the people who had recovered from the disease. So the idea is a person has had COVID, has recovered - as the vast majority will - has developed antibodies - as the vast majority will, we believe the antibodies are protective, although we're not 100% sure about that. You take the blood out of those people just like donating blood, but instead of the red part of the blood, you basically distill it down so it's just the antibodies and you then infuse it into someone with severe COVID.
And the evidence on that is a little bit scant here, I'd say, than the remdesivir. There have been a few early trials that showed some possible benefit in very sick people, and I think we have gotta wait a little bit longer to be sure.
But I think those are sort of the two most promising medicines that are out there so far and they're both just for people that are very sick in hospitals to prevent more deterioration. The hydroxychloroquine studies that were touted by the president, the majority of them are coming out negative with some very concerning side effects. So I think there's very little enthusiasm for that right now.
Okay, let's get to the questions, and these have come in via our email inbox askus@kcbsradio.com.
Risk level in apartment buildings: what is the exposure risk in a typical San Francisco apartment building in our hallway or common area, where residents don't wear face coverings and there's no resident manager? Isn't it true that even if someone became ill with the virus, they're not required to tell anyone else?
Yes as far as I know that is true, people are not required to tell anyone else and that will be the interesting thing that we're gonna have to sort out as we move into a phase where we're testing people when they're positive, asking them who they have contacted, then contact those people and test them and all of that. It really depends on the goodwill of people. I think most people are cognizant they have an obligation to make sure that folks know about this in order to be sure that people take the precautions and get tested.
In terms of an apartment building, a lot of it the devil's going to be in the details there. What we know from the cruise ship and the Theodore Roosevelt - the warship - is that living in a closed space, the virus gets around pretty well. And some of it is probably from people coughing on each other. But some of it is from virus being on hand rails and other shared services, elevator buttons and stuff like that.
So if I were in an apartment building and first of all, I would be very careful about surfaces because the virus can live for a couple of days on a shiny metal surface. So when moving in and out from my apartment outside and back in again, I need to be wearing gloves or be very careful about what I touch. And the key thing is not - you don't get it by touching something, you get it by touching something and then touching your nose or your eyes or your mouth. And so if you have to touch something on your way in and out of your apartment, you want to be absolutely sure that you clean your hands either by washing them or by using a gel before you touch your hands or your face. And sometimes the mask - one of the most helpful things about the mask is it sort of reminds you about that, rather than it blocking the virus.
So, yes, be somewhat careful. The other thing we know from apartment buildings, getting in and out to your apartment, that the virus is quite transmissible within families and there have been lots and lots of cases of one family member infecting others. So if you live with other people and you're sick, you need to go ahead and get tested as quickly as possible and segregate yourself to the degree you can from the other people living in your apartment.
Next question: as a lay person with an autoimmune disorder, sounds like the effects of COVID-19 on the body are a lot like severe, really rapid onset Lupus. Is there any data on how patients on immunosuppressants for autoimmune disorders fare when they contract the coronavirus?
I don't think - the idea that it is like Lupus, I don't think is quite right. It really is like a bad respiratory infection, although we now know that it can affect all sorts of other things, including the skin and the gastrointestinal tract. It has a lot of manifestations. In that way, it can be like Lupus.
But the sort of crux of the question is, are people who are on medicines to suppress their immune system, whether it's for Lupus or inflammatory bowel disease or cancer treatment, whether they're at increased risk. And the answer is probably yes. And it's a little hard to distill out how much of that is from the medicine they’re on and how much of that is from the underlying disease they have. Clearly, if you take two people of the same age and one has an underlying disease, and the other doesn't, the one with an underlying disease is probably no more likely to catch it, but more likely to have a bad outcome.
And whether the person who is on just immunosuppressives but is otherwise healthy - I'm not sure why they would be on immunosuppressives - is that high risk? I think it's a little bit up in the air, but I would assume that as well. So if I had an underlying immune disorder and was on immunosuppressives, even if I was younger, if I was say 40, I would be treating the world around me more like I was 60 or 70, meaning that I would worry that I would have a higher risk of a bad outcome if I got it.
Next question has to do with smoking. This questioner says even though I'm always wearing a mask, I can still smell the smoke of a person who is smoking and passes near me. Can COVID-19 be spread by an infected person smoking? And what if the smoke reaches your eyes?
That's a great question. There's no evidence, I think, that it can be spread in the smoke. But the smoke is almost a metaphor for the spread of virus from someone to someone else. And some people have asked me before, is it safer to be outside than inside? And the answer seems to be yes. And the analogy is, if you're in a room and someone is smoking, you see the smoke all around you. And if you're outside and someone is smoking, chances are the smoke is going to dissipate in this huge pool of air that's moving.
There's no evidence that the fact that the person is smoking makes them riskier than if they weren't, other than the fact that they may be more likely to cough. The fact that you get smoke in the air, let's say 10 or 15 feet from a smoker, it’s carried a different way. It's easier for smoke, which is much smaller particles than the virus to move around. So if I'm sitting 20 feet away from someone who is smoking, I'd still feel safe from the standpoint of the virus. That distance of six feet seems to be the safe distance and the issue is the smoke has different characteristics in terms of its ability to spread, then virus.
Can you explain the new early signs of infection related to COVID-19 like foot pain or swelling? Is that true?
I haven't heard foot pain or swelling, but they have expanded the list of worrisome symptoms as we've come to see that sometimes people just have muscle aches, just have chills. I think it's now well understood this idea of a loss of taste or loss of smell.
There is a higher rate of blood clots in patients who have COVID. So if someone came in with undiagnosed or sort of a surprising blood clot, that would make me think of COVID in a way that I certainly wouldn't have a few months ago. But there are a whole lot of other reasons why people have that. Just foot pain by itself, I haven't heard of that.
I continue to be puzzled by the outcry for more testing. What reassurance does a positive antibody test provide?
Really interesting and complicated question. So let's start with the test characteristic. How good is the test? We know that the antigen test - the ones that we have done, the nasal swabs or the back of your throat swabs - are quite accurate and we have a lot of confidence in them. If you have symptoms that you think might be COVID and you get tested and the test comes back negative, you could be reasonably assured that you don't have it. Although there certainly have been cases where you test again a few days later and it turns out positive. That's the virus test. That's the test for, are you sick with COVID, is it an active virus in your body.
The antibody test on the other hand is, you have had COVID, you're probably at least 10 to 12 days into it and now your body, we hope, develops antibodies to fight the infection. None of us have antibodies to start with because this is a novel infection that did not exist until six months ago. And so then the hope is you clear the infection and your body develops antibodies. The hope - I'd say expectation, but we can't say this with 100% assuredness - the strong hope is that those antibodies will turn out to be protective, meaning you're not gonna get infected with this virus again. And that's the whole principle of a vaccine. A vaccine is designed to artificially give you antibodies that hopefully will prevent you from ever getting infected in the first place.
The problem with the antibody tests that are rolling out now is they're not perfect. And if you do testing in a population of people who are - this gets into complicated math - but if you do testing in a population of people that are unlikely to have the thing you're testing for, if the test isn't perfect, there's a decent chance that if someone tests positive, it's going to be a false positive. That's the concern about the studies that were done of Santa Clara several weeks ago, I think we talked about where the numbers came out surprisingly high in terms of the number of people that had antibodies. They said about 4% of Santa Clara had antibodies - that surprised most scientists, epidemiologists, and my feeling is that they're probably not right, that the prevalence in the Bay Area of antibodies, the people that really had COVID and have cleared it is probably going to turn out to be about 1-2%. I think it's a reasonably good bet that those people are protected from getting it again.
The problem is, the 98-99% of the rest of us have no antibodies and are no more protected against getting COVID than we were six months ago, and there still is virus in our community. So when people wonder why - you know we have really dodged the bullet here in a major way- why didn't the mayors and the Bay Area counties loosen things up this week? And the reason is that there still is virus in the community. There are still new cases being diagnosed. The number of patients in hospitals and in San Francisco is pretty stable, in fact, it's picked up a little bit in the last week, and 99% of us are not immune to it.
So the conditions that exist now are not fundamentally different than the conditions that existed a couple of months ago. So we still - we feel very good about how we've weathered the first part of the storm - but we still got to be very careful.
Next question. Do we know how many people who have died from COVID-19 had underlying medical conditions and the role those played?
In a rough way. There are a lot of studies, pretty clean ones that are coming out of New York now that are looking at the mortality rates and it's clear that many people who die of COVID have underlying conditions.
The tricky part of that is disentangling the fact that it's very clear that it’s age related. So if you're under age 50 your risk of dying is quite low, although absolutely not zero. If you're over 60 the risk goes up, and particularly if you're over 70 or 80. And most people, as it turns out, over age 60 have some chronic condition. If you sort of inventory 100 people over age 70 particularly, you're gonna find heart disease, lung disease, high blood pressure, diabetes in a pretty good percentage of them. So it's not entirely clear whether it's just the age and the fact that older people have chronic conditions or it's the chronic conditions themselves. There's no question that having a chronic condition increases your risk. So if you're a 40-year-old who is perfectly healthy, your risk of getting sick from COVID is lower than if you're a 40-year-old who has active cancer or a 40-year-old who has diabetes.
What's the latest assessment of the percentage of people with COVID-19 who are asymptomatic?
The best numbers say it's about 40%. It might be even a little bit higher, but the challenge there is, is it asymptomatic or pre symptomatic? And that sounds like it's trivia, but the number of people who go through the entire course of COVID and never have any symptoms and they feel perfectly fine is probably about 30 or 40%. Then you have a number of other people who, if you test them, they are asymptomatic and they have virus and they're capable of spreading it. And then if you wait a couple of days, they now develop a fever and shortness of breath. So at the time that you have the infection and are capable of spreading it, it may be up to 50% of people are either asymptomatic or pre symptomatic.
This is one of COVID’s superpowers, which is that if everybody was sick, this gets a hell of a lot easier. You know, we can check people for their temperature, we can ask them how they're feeling. If they're feeling bad, they do a test, they stay home. In some ways it's not that hard. Once you say up to half of the people who have this infection and are capable of spreading it are asymptomatic, then the whole strategy of how you contain this, how you figure out where it is becomes much, much harder because it becomes this very stealthy thing that's kind of lurking around.
And that's why the strategies about when do we open up become just harder to do than they would be otherwise. Because people may say, “I'm young, I’m healthy, I'm at very low risk of getting very sick from this thing. Why are you making me not able to go to a bar or go to a restaurant or go back to work?” And it's a perfectly logical question, but the reason is you can get it, you can be carrying it and you may not get sick, but then you come in contact with your parents or your grandparents - this could be true for kids at school, too - and if they get it, they get deathly ill. And so it really makes it many times harder than it would have been. What we thought in the beginning was everybody has symptoms. We now just know that that turned out not to be true.
Okay, let me see if I can slip in a couple more, such a long list this morning and I don't think we're gonna get to all of them. If San Francisco hospitals have a manageable but stubbornly persistent number of cases, doesn't that suggest we're already at the amount of social interaction we can handle?
It's a terrific question. I think the answer is we've got to be very careful about when we loosen up and what loosening up looks like. If loosening up looks like we begin opening some businesses but people stay six feet apart, everybody's wearing masks, then I'm reasonably confident that we will not see things worsen and that things can remain stable. We can kind of weather the next several months as we wait for hopefully treatments and vaccines.
If loosening up means people say, “alright, good, we dodged the bullet we’re good” and they don't wear a mask and they don't stay apart from each other, then there's no reason to believe that we won't have a surge.
And I guess we make this the last one, we got to get you back to taking care of patients and the important stuff. What happens to all the PPE, the masks, the gowns, etc after they're used by front line workers? How are they disposed of after they're used?
There's a whole system of secure disposal that all hospitals have where they're put in separate bins, not with the regular garbage and then sequestered. And I don't actually know where they go from there, whether there are separate landfills or burned or whatever. But I think it's a safe process.
And it's also important to realize that the virus, as I said, when it's on a shiny metal surface it can live for two to three days. When it's on clothing or on a shopping bag or on a piece of paper, the best evidence is it can live for several hours. So you take a piece of PPE that was thrown away, if you touch it a week later, it's safe.