Answering Your Questions About Coronavirus Transmission

KCBS Radio is answering your questions about all things coronavirus every weekday at 9:20 am
By KCBS All News 106.9FM and 740AM

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 Sierra Pacific Financial Advisors.

Today we're looking at everything from the virus itself to the uptick in cases in California with Dr. John Swartzberg, clinical professor emeritus of infectious diseases and vaccinology at the UC Berkeley School of Public Health.

Let's start with something in the news this morning, this study out of the United Kingdom on a fairly common steroid drug called Decadron, dexasone, dexamethasone - I guess it's known by a lot of names - and finding that in cases of severely ill people in the hospital, maybe needing either oxygen or a ventilator, this drug seemed to make a difference. Have you had a chance to look at the report that's out so far?

Well I've looked at the report that's out so far, it's not been published and that's an important feature to keep in mind. We need to have it published, peer reviewed, and then we can really critique the data. That said, these preliminary reports put out today do suggest that dexamethasone will help in those severely ill people that you were describing. Frankly, I'm not really surprised because doctors have been using this drug for a while now in severely ill patients with COVID. The thinking behind it is that dexamethasone is a very powerful anti-inflammatory drug. It's a steroid, it's like cortisol and it will tamp down the inflammatory process. Our current thinking about severely ill people with COVID is that it's our own inflammation that's causing a lot of the problems, so using something that would tamp that down should help. And if this report turns out to be accurate, it looks very good on paper, that is, it was a double-blind controlled study. So hopefully it's right and I won't be surprised if it is.

And of course, we've talked about this before with you and other experts and that this is sort of a perverse situation with our immune system and how sometimes it's our friend and sometimes, in cases like this, not so much.

I know, this is one of the really, I guess you could call it fascinating things about this virus and its interaction with us. In most people it doesn't do this, most people who get infected with the virus don't even get sick at all. But in some people it causes their immune system to overreact, we lose its balance. The immune system is there to get rid of the virus and then to allow for healing, and we don't want to continue this inflammatory process because that causes a lot of tissue destruction. Why some people get this and others don't, we just don't know yet. But this drug dexamethasone does block that inflammatory process, so it plays a role.

Another nice thing about this drug is it's available. It's been around for years, decades. So we've had enormous experience with it, there's a pipeline in terms of production, so it is available to us.

Let's get to these questions then from our listeners, which have been sent in to

This came from someone who must have been paying attention to the news this morning: it seems like there are more and more reports of drugs that help treat people who catch COVID-19 (remdesivir and now the new report about the steroid being used in England).  Could you weigh the pros and cons here? On one hand, it seems like if we know we could keep people from dying, we could maybe make different decisions about how to move forward. On the other hand, might these provide a false sense of security?

Well, I think that's a great question. Yes, people shouldn't read this report or the report about remdesivir and think, "well now we can cure people so I don't have to worry as much." No. These are drugs that have just been used in very severely ill people and suggest that it will save some lives. People died receiving dexamethasone, people died receiving remdesivir, so these drugs are not a guarantee that we're going to be fine. But what they are is a step in the right direction, they're a proof of concept, if you will, that we can develop drugs that can modify our immune response or modify the virus' interaction and help us. So, one step at a time. That's where these are encouraging.

Can you explain why we are seeing more and more cases but the number of deaths doesn't seem to be climbing as fast?

One of the reasons we're seeing more cases is because we're testing more. We haven't been testing enough, I think everybody knows that. We've been woefully behind in testing enough people to really understand how this virus is behaving. The numbers have really increased very significantly in the last few weeks and that reflects some of the increases in the number of cases, but it's not a sufficient explanation. One of the other reasons we're seeing an increase in the number of cases is because people are leaving sheltering in place and going back into the workplace and back into society. Another reason is people, for a variety of psychological reasons, have just had it and are not practicing safe enough behavior when they are out. That is, they're not wearing masks and they're not practicing social distancing. That's another reason for the uptick in cases.

The number of deaths has remained pretty stable, although in most of the counties in the Bay Area there's a slight increase in the number of deaths. The number of deaths is one parameter to follow, but remember, when somebody dies they probably got infected around a month ago. That is, it takes a few days after infection to get sick and a few days after that to get sick enough to get in the hospital and then it's usually a week or two weeks after you've been in the hospital - and sometimes a lot longer - before you die. So people dying today reflect what we were doing when they got infected a month ago. It's not a very sensitive parameter of what's happening right now.

Do we know for sure if warmer weather slows the spread of the coronavirus?

No. We don't. We can't possibly know for sure, because this virus hasn't existed - at least in our latitude - in the summer. So this is going to be our first summer experience with SARS-CoV-2, the virus that causes COVID. We'll know after this summer whether we think it made any difference.

We do have some hints that the summer may not make a difference, and those hints come from other regions in the world that have experienced summer or never really reached low temperatures because they're closer to the equator. We're seeing an awful lot of cases in those parts of the world too. That would suggest that the summer may not make a big difference. I do think the summer will make a difference in one respect: we know it's a lot safer to be outside than inside. And of course in the winter when it's cold, we're mostly inside. And in the summer when it's warm we're spending a lot more time outside. The more time we spend outside, the less infections we're going to see.

As a San Francisco pedestrian, I am concerned about the trend for restaurants to open sidewalk tables. These seem to be less than 6 feet from where we must walk. Since a mask does not protect me, where do I walk?

I know, I think this listener has a very valid concern. If you're not practicing social distancing, you're putting yourself at risk even with a mask on. The listener is also correct that masks are protecting other people primarily from you, if you're infected, and they give you only a modest amount of protection. If the sidewalks are being occupied by other people dining, you're going to have to find a way to walk around them and to remain at least six feet away from those folks.

And this does raise the time and exposure question. Obviously there's not a calculator we can plug numbers into because there are too many variables, but how scared or how nervous should people be about a brief encounter like walking past somebody on a sidewalk as opposed to being stuck in an elevator for a minute.

Exactly. They shouldn't be scared. I can't tell you that there's a zero risk in that event, but there's a very low probability of getting infected if you're walking by somebody who is infected. And you made a correct statement in that it's time. If you're around somebody who has been infected for a period of time, that's much greater risk than if they're right next to you.

Let me fill that out a bit. Typically in the hospital, we say an exposure really requires a number of minutes. Some people are using, for example, 10 minutes of exposure before you're really at high risk of getting infected. Outside of the hospital setting we're being more liberal and saying 15 - some references suggest 30 minutes of exposure. So time is critical. But tucked into that, we have to remember that if I'm standing next to you and I've got COVID and I'm only next to you for 15 seconds, but in that 15 seconds I cough on you or sneeze on you or even talk loudly in front of you where lots of droplets are expelled, that would be an exposure. So it's time but it's also the quality of what's happening when you're in proximity to somebody.

My wife and I are in the vulnerable group, over 75. When the shelter-in-place orders are relaxed, is it okay to have our home cleaning service (a wife, husband and additional person) clean our home while wearing fabric masks and gloves? They are cleaning our residence for about two hours. If okay, should we leave while they are cleaning or is it sufficient to always be in a room not being cleaned with our masks on?

Boy, whoever wrote that question was probably listening to my wife and I talking about this. I think a lot of people have this question. There's a very low risk of people spreading something in your house who are coming to clean, but those folks should be using precautions. So what I would suggest strongly is, you tell the people who are working in your home to please wear a mask, please put on new gloves when you're in the house. Those are the things you can do. Sit outside while people are cleaning your home, I think that would work very well.

The flip side of this question should also be addressed. The people who are cleaning our homes are putting themselves at risk because they're not just cleaning our homes, they're being exposed to a variety of homes. And so I think we could flip that question and say, "what are the risks to people who are coming into our homes? And how can we make certain that we wouldn't invite them in if there are any risks that we can ascertain?" So it cuts both ways.

And let me expand that a bit because I've had that question asked of me a lot. You touched earlier on the outdoor nature of life here - we're pretty lucky climate-wise - about doing things outdoors like gyms under a tent rather than outdoors or a hair salon setting up outdoors. Safer?

Safer, but not safe. Safer because outdoors, particularly on a day like today with a breeze, you're getting a lot of dilution of anything that comes out of people's mouths. So that's safer if you're outdoors rather than indoors where things can't blow the particles around and dilute them as much. So yes it's safer outdoors, I would much prefer getting a haircut outdoors than indoors. But I still think that people in very close proximity to you - and this goes back to what we were just talking about - to have your haircut, you're going to be in very close proximity for more than 15 minutes. That's a risk. Outdoors the risk is a little bit less, but it's still a risk.

Since I have auto-immune conditions (severe allergies, scalp psoriasis) am I more likely to have an exaggerated immune response to this virus which seems to cause the worst illness from it?

We haven't seen that. It's a very interesting, thoughtful question. It's not clear that people who have other auto-immune diseases are more likely to have severe disease from COVID. Now, tucked into that question is that if you have an auto-immune disease and you're on a drug that makes you immunosuppressed to control the auto-immune disease, we know that people who are immune suppressed are at increased risk of developing COVID.

I've seen small filters, about two by three inches, marked PM 2.5 that you can buy. Would these be good filters to slip into a cloth mask to help protect me from contracting COVID?

They may offer a modicum of increased protection but not much, because the masks we're using don't create a tight seal around our nose or around our cheeks or around our chin. So when we take a breath in, we're going to suck air in from where there's the least amount of resistance, which means around the mask as well as through the mask. So sure, adding something that would block the particles from coming in somewhat through the mask might help a little bit, but we're sucking an awful lot of air in from around the mask.

If I have no symptoms and I've not been exposed to anyone with COVID-19 that I know of, is there a need to get tested?

No, if you're otherwise in good health. Unless you're working in a situation where you could spread this, it may be important. If you're asymptomatic you don't need to be tested. There are some exceptions to that, but that's a general statement.

I'm a frequent rider of public transportation like BART and Muni. How high is the risk of getting infected due to people not wearing masks and sneezing, if public transportation is using air conditioning systems? I usually wear a mask but I don't wear eye protection.

The air conditioning system is not, per se, a risk. The air conditioning system is blowing air through, it is circulating air and that is somewhat helpful. All of that said, the worst place you can put yourself is in a crowded environment that is confined inside. And unfortunately, airplanes and BART would be exactly that. Mass transport is a risk for contracting this infection.

I'm a retired RN. Many people want to know how isolation and quarantine orders are enforced in the seven Bay Area counties. How do we know that those ordered to self-isolate are not wandering around spreading the pandemic? This is a huge concern.

I don't know if it's a huge concern or not, I haven't seen any studies about that. I think most people are responsible when told that they have to self-quarantine. So I don't think there's clear data in the United States about that.

If you look at Taiwan and South Korea, for example, people who are put in quarantine are monitored electronically. If they remain in quarantine they're actually, in one of those societies, given money to stay in quarantine. But if they leave quarantine when they shouldn't be, they can be severely fined or even imprisoned.

Our pregnant daughter is planning to go to Colorado in August. How safe is it for a pregnant woman to fly during the pandemic?

Probably no different than somebody who's not pregnant. It's not the pregnancy that's going to put her at risk, it's the flying.

Regardless of the news that there are encouraging treatments, there's still no cure and no vaccine. Given the history of the second and third surges of the 1918/1919 pandemic and the proven benefits to the population of everyone wearing masks, how can the medical community play a part in creating legislation to mandate masks during a pandemic? It seems logical and intelligent to follow the science. It's like mandating wearing seat belts.

It would be nice if our country followed the science much better than it is. And the problem really stems from the top, where we have an administration that seems to not follow the science at all.

This transcript has been edited for clarity.