Answering Your Questions About How COVID-19 Has Changed

Stan Bunger
July 06, 2020 - 2:12 pm

    As we continue to navigate these unprecedented times, KCBS Radio is getting the answers to your questions about the coronavirus pandemic. Every morning, Monday through Friday at 9:20 a.m., we're doing an "Ask An Expert" segment. Each day we'll focus on a different aspect of this situation.  

    This week, KCBS Radio's Stan Bunger had a chance to speak with Dr. Brian Schwartz, Professor of Medicine, Division of Infectious Diseases at Zuckerberg San Francisco General Hospital, about the ways the treatment of COVID-19 has changed since the early part of the pandemic, and how that ties in with the lower death rates. 

    Let me start with a general question for you, now that we’re several months in. How do you feel things are? Stable, scary, somewhere in between? 

    If you asked me a number of weeks ago, I would say that I feel like we’re moving in the right direction, but I think the recent events across the country, with the rise in cases, is very disturbing and scary. I wish I was feeling better than I am right now.  

    And what about the kinds of cases? Early on people were dying quickly, not so much lately. Is there any sense you have of who you’re seeing now? 

    I can tell you from being in the hospital caring for patients just this weekend that there are still many patients who are getting ill and have severe disease requiring prolonged hospitalization in the ICU, and people are still dying from this infection.  

    How many days from a possible exposure does it take for the virus to, number one, replicate enough to show up on a test, and number two, replicate enough to normally show symptoms in someone?  

    So, the number of days from exposure to the onset of symptoms is definitely variable from person to person. We know there is a certain percentage of people that will be exposed, infected, shed virus contagious, but never have any symptoms. So, that is one of the disturbing and challenging issues with this virus that’s different from other diseases. I would say, from the onset of exposure to first being contagious, it could probably be anywhere from three to six days, although it varies from person to person. And then, the onset of symptoms could be a little later, could be a little sooner, but somewhere around that window. 

    What does asymptomatic really mean? Does it mean that the person may develop symptoms as time goes by? Or does it mean that the symptoms will be mild, or that there will be no symptoms at all? 

    So, there are twp terms that you may have seen when people talk about COVID infection. There's the term asymptomatic. We say that when somebody is asymptomatic that means they have been infected, they're contagious, but they never have any symptoms at all and they resolve. The other term you may have heard is something called pre-symptomatic. That we define as somebody who’s infected, is contagious, has no symptoms on this day, but four days later goes on to develop symptoms. We call that the pre-symptomatic period.  

    Are there people who will never develop symptoms?  

    Yes, there will be people who – and I think we're still trying to understand what percentage of the population this will happen in, but they’ll be people who are infected, are contagious, and never develop symptoms.  

    We hear more and more about people testing positive, but with no symptoms. Isn't this a sign of "herd immunity"? How can a person develop antibodies without first having the virus in the body? Yet, if the antibodies work, won't they show no symptoms? If we had 100% "herd immunity" will "no one" or "everyone" test positive? There’s a lot to unpack there.  

    There is a lot to unpack. I want to start by going back to the idea that you could be infected, you could be shedding and be able to transmit infection to other people, be contagious, and never have symptoms. That is very different than somebody who has immunity. Let's say I was infected. My body’s immune system developed the ability to control the infection. I’ve cleared it. Then, if I got exposed again later, I would not be infected, I would probably not be contagious and shedding to anybody, and so I'd never have symptoms. Those are two very different scenarios.  

    Then, talking about the idea of herd immunity, we would need so many people to be infected and then develop immunity to get herd immunity, that there would be many many people who would get sick and die and be in the ICU to get there. So really, the goal right now is to prevent the spread of disease, and then hopefully get to a point where we can get a vaccine.  

    Is it true that the coronavirus has become much less lethal and it is losing its "potency," and does that explains why we have less daily death while cases are rising at record high? 

    That is not true. The virus is still as potent and severe as it always has been. There are probably several factors that make things look like it’s less lethal. A couple ideas around that are, one, early on our testing was more limited. So, everybody who came in and got tested was sick, and a certain percentage of them would go on to die or go to the ICU. Now, as our testing is being expanded – and we may even be testing people with more symptoms – that total denominator of people being tested and being positive, is bigger, and probably the number of people that are going on to die from it is smaller. So, it's just the total pool number of people that we’re testing is bigger. I think that’s a disconnect. I think that a lot of the patients that are higher risk, who are older, have other illnesses that put them at higher risk, are doing a good job of avoiding contact. So, maybe the people that are getting infected have lower risk for having death when they do get infected.  

    Early on, I heard that low blood pressure was thought to be an underlying condition. I am 71 with high blood pressure controlled with daily meds. Is that still considered an underlying condition in addition to my age? 

    Hypertension, high blood pressure, is considered to be a risk factor for having more severe disease. Yes.  

    Has anything new been revealed on long-term internal damage post COVID, and whether asymptomatic people are also at risk as well as people w symptoms? 

    That is a great question. I think there's a lot that we still need to learn. I think that patients who have bad COVID and extensive lung disease, even if they’re able to clear, probably have some lung damage and will take a long time to recover. It's possible that they have permanent scarring and damage to their lungs that will prevent them from being able to exercise and do things as well as they want to in the future. Tell me again the second part of that question.  

    Whether people who were asymptomatic, but infected, are susceptible to these things long-term.  

    Great. It is not clear that patients who are asymptomatic will have complications if they never have symptoms.  

    How does the coronavirus compare to the influenza virus in terms of morbidity and mortality? Can you quantify it? For example, is it two-times as deadly, 10-times, about the same?  

    I would say that it depends on the season and the flu, but probably about 10-times, at least, more severe than influenza. 

    With some studies suggesting that the antibodies don’t provide immunity against COVID-19 for very long, possibly just months, how will vaccine manufacturers know how long their vaccine will provide immunity? Or, will people receive the vaccine and the immunity level will have to be determined at some future point? 

    That is a great question, and this is why it's being studied. This is why we don’t just make a vaccine and not do very rigorous studies. Moving forward, I think that we will see over time, and that people will be routinely tested for antibody production. This may be a vaccine where a single dose, or two doses, in a short period of time may not be enough, and that we need multiple booster shots over time. Or, we may need it annually like we do influenza. I think there's a lot to learn here.  

    Do we have a reliable antibody test yet?  

    There are many different antibody tests that are available on the market. There are some that are better than others, but we do have some that we do feel like are generally reliable. Some of the challenges with the tests are if you test too early in the disease you may have not made antibodies, so it wouldn’t be reliable that way. Also, I think when we're testing populations that are low risk, there's always a chance of a false positive test. Those are issues with some of these tests as well, but in general we have some pretty reliable tests.  

    How accurate is a negative antibody test?  

    I think there are a number of factors that go into that. If you truly had COVID, and again if you test too early you may have not made antibodies. There are some suggestions that people with more mild disease may not have a positive antibody test. And then, as one of your callers had mentioned, we still don’t know how long -- even when your antibody becomes positive -- how long it will last for. 

    Maybe I can ask you a sidebar here, to talk for a moment about this antigen test. The FDA Gave an emergency use authorization to Becton Dickinson today for this. This sounds exciting on the surface. It’s a test that gives a result in 15 minutes. It uses a machine that apparently is all over the place, kind of a cell phone sized device, and could widely expand the testing. So, explain how antigen tests work and what you know about this one.  

    Great. So, the test that most people are aware of, in terms of diagnoses, is PTR, where we’re actually looking at pieces of DNA, RNA of the virus. The antibody test is actually looking at your body’s immune system response. So, actually looking at antibodies that your immune system made. Antigen tests are still looking at particles, pieces of the virus. I need to look at the specific test that you're talking about, but I know of the antigen test that has come out a number of weeks ago. I think although the speed, the rapidity of getting the result is very exciting, the sensitivity, or the ability to get a correct positive test, was lower. I would need to look at that data, but that was one of the concerns of one of the recent antigen tests: although you could get it back really fast, that it was not as sensitive or it did not have the same ability to pick up positive results as the PTR test.  

    Okay, next question. Why can't the statistics regarding testing, positive percentages, ICU beds remaining, etc., be reported in per-capita figures so we could better compare, for example, Santa Clara County to Contra Costa to San Francisco? The raw numbers are good for curiosity but because the counties vary so much in geographical size and population, it makes the comparison difficult.  

    I agree. I think more data and looking at it in lots of different ways would be helpful. I think the point is very reasonable.  

    Okay, next one. What is your recommendation if I was to go camping in an open campsite? Others will be in the campground, but tents will be socially distanced. What would be the right protocol?  

    I think that the standardized practice of masking and social distancing, hand washing, should all be at play. Obviously, I'm assuming the people you're camping with are people that you normally are in regular contact with. I think, again, good hand hygiene, distancing, masking whenever you can and definitely if you seem to be closer than 6 feet.  

    I have not heard anything regarding protection from the virus through droplets into the eyes, although I've heard the virus can be passed on through the mouth, nose and eyes. Should we be wearing face masks or shields, too, along with mouth coverings?  

    In the healthcare system, directly exposed to patients, we have been using face masks as part of our personal protective equipment. I think in the average community setting, the addition of a face mask, there's probably not a lot of benefit for doing that.  

    As a retired health professional, could your guest please discuss the long-term effects of COVID-19, especially as it affects youngsters who are currently behaving recklessly and irresponsibly thereby seriously affecting their quality of life or significantly shortening their life?  It appears it is time for an informative emphatic concerted public service campaign. So, younger people, do they bounce right back from this?  

    I can tell you looking at the data, in my experience at UCSF, we definitely have younger patients who get ill in the ICU. Younger people can die of this disease. I think that it's really important on several levels to remember, one, that as a younger person you still are capable of getting severe disease and dying, but also remembering that you are a vector that can carry this and give it to other people who are at risk. Just wearing a mask is going to do so much to prevent the spread of disease to other people, your loved ones. You can do a very small thing to make a big difference to help us control this epidemic.  

    From a recent New England Journal of Medicine article, our genetic data confirmed blood group O is associate with risk of acquiring COVID-19 that was lower than that in non-O blood groups, whereas blood group A was associated with a higher risk than non-A blood groups, researchers concluded. Do you have any info on those who have dominant A+ recessive O- genes? Do recessive O genetics help in any way? 

    I don’t think it's really well understood why those blood group associations exist. I agree, I've read the article. I know exactly what they’re talking about, but the why is not understood and I don’t think I really have much else to add to that question. 

    Okay. Here's one that follows up on the question that we had the other day. This was the suggestion to conduct a comparative vaccine trial in the prisons with volunteer staff and inmates. At the time, our response, and I think this might have been Dr. Bob Wachter, who said it would be unethical to throw prisoners into a test like that. Now, this question wants to know, what if the test didn’t involve a placebo? Let’s say you compared all the vaccine candidates versus the outcome of those who didn’t volunteer to take a vaccine at all. Would this be ethical and could it be a way of looking at a vaccine more quickly?  

    I agree with what Dr. Wachter said. I didn’t hear the interview, but involving anybody in the correctional facility space in research studies is not something that we do or that is considered ethical. I would leave it at that.  

    It would help if we really knew where the new cases are coming from (in other words, did people catch it at a bar, or a political protest, or the supermarket, etc.). Is this something the public health departments know but aren't saying, or is it impossible to determine? 

    I am sure that the public health department is not keeping information. I don’t think we know specifically where outbreaks are always coming from. They work really hard to do tracking, but I think there are probably certain living situations, like nursing homes, where there’s lots of data of severe outbreaks resulting in a lot of morbidity and mortality, but we don’t always know where these are coming from.  

    I live in San Francisco. Should I be worried about the reports of increasing hospital bed utilization. What's the situation at San Francisco General? 

    I think, in San Francisco at this time, we are having more cases, some locally, some are coming from other areas, where we’re helping to care for patients when other healthcare centers are becoming overwhelmed. I think we're still in fine shape and our capacity is okay.  

    Do we need to continue to use disinfectant wipes on packages from say, Amazon or FedEx? 

    I think every person has their certain level of risk that they’re comfortable with. I think that doing that is reasonable. Also, there's a time where the virus will just stop being able to be transmissible. I think I was reading an article where Anthony Fauci said that he just leaves his stuff for two days out on a table before he touches it. I think, overall, the risk of transmission from that mechanism is very very low, but each individual needs to do what feels right for them. I personally do not spray my Amazon containers before I open them. I wash my hands a lot.  

    Will the use of sanitizer in toilet water eliminate or mitigate the risk of the virus being spread by toilet plume aerosols when flushing a public toilet. Basically, can I spray down the water with some blue port-a-potty stuff and stop the virus from spreading?  

    I don’t think we have any data that suggests this is a way that the virus would spread, and I don’t think that that’s necessary.  

    I'm not trying to start a political fight here, but President Trump says 99% of coronavirus cases are harmless. Would you agree? 

    No.