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.
Today we continue to look at the rising cases across the country and ways we can all limit the spread of disease with Dr. Peter Chin-Hong, infectious disease specialist at UCSF.
Let me start by asking you to give us your broad assessment of where we stand right now, vis-a-vis where, maybe a month ago, you might have thought things would be today.
Totally. A month ago I was looking forward to a haircut, I was looking forward to reopening and may be venturing forth, to maybe trying out some outside dining. But right now I scaled back my expectations. I'm starting to feel nervous and a little bit anxious.
So what happened here?
So there was the Memorial Day effect in California. I think people were tired, you know? We were really good, we were unified for a long time. People were being really good. California was a miracle. California, we looked at the other states and people were looking at us for advice and how we did it. And now, Memorial Day was a nice weekend and people just let loose. They went out, particularly starting in Southern California with the beaches and that's what prompted Governor Newsom to close down some of the Orange County/Huntington Beach areas. And I think it just took off from there.
The challenge for a lot of laypeople is to figure out what the message really is. We're told outdoors is better, but then the beach isn't good. You need exercise, but you can't go on the beach. So what is the best way to sum up what we really want people to hear?
Totally, I think part of the problem is somewhat confusing messaging and the mixed messaging. Part of it is because as we moved on in the epidemic, we understood more about the science, and I think we have a better understanding now. Although I would say that every hour is a new day with COVID-19.
I'd summarize it by the three W's in terms of the ways we can protect ourselves, and forget about the laundry list of 20 things that I think people came out with originally. You boil it down to three things to ward off COVID-19. You wear masks, you wash your hands and you watch your distance. And if you had to choose one thing, I would wear my mask.
That does distill it down, now you've got it down to a phrase like "click it or ticket" or "don't drink and drive" or "don't mess with Texas," right?
I know, exactly.
Why has it been so hard, though, for the health establishment and the political establishment to do that?
Well, I think because within our highest echelons of leadership there was one feeling and then there was the public health officials that were saying something else, so I think nationally we didn't have a very consistent message. And I think in the state we did a lot better. There was a better alignment between science, public health and leadership. And I think in California that's why we probably did much better. And, of course, the Bay Area was the most conservative. I think London Breed was really prescient in closing down or sheltering in place, the first in the country. And then three days later, California followed generally. So I think the alignment between science and leadership sounds like a no brainer, but it hasn't been the case nationally.
Okay, let's get to questions sent in by our listeners to email@example.com. First one: are we able to determine where these new cases are coming from? By that I mean, are they from workplaces or bars or gyms or... ???
Yeah, that's a great question. I think we get some information from contact tracers. Contact tracers are like the gumshoe detectives in this whole business. They get alerted about the positive cases, then they go and investigate. They asked the positive cases, who have you been around in the last week or so?
So I think we've been getting some answers in our area. And I think some of the most compelling outbreaks that we've seen from these contact tracers were around graduation parties and a lot of indoor celebrations that multigenerational families were having behind closed doors. And I think it's a little bit insidious because you know, you're seeing your uncles or your aunts - you don't think of them as high risk - probably for the first time in a long time. And you put 50 people close together having a barbecue, and even though you know these people, nobody is necessarily obviously ill and the nature of this disease is such that you can't tell who has disease or not, because there's a lot of asymptomatic spread. So that was the focus of a lot of transmissions recently in the Sacramento area in particular, Solano, I think.
And then there were work parties as well. And then we got some information from other parts of the country from contact investigators as well. Like in Texas and Mississippi, they were associated with frat parties and pledge parties, so a lot of indoor activities. And certainly the biggest and scariest example of an indoor situation is what's happening in San Quentin now, with over 1,000 prisoners infected.
In fact, that gets to one of the questions we had here. Would it be possible to conduct a stat comparative vaccine trial at San Quentin? Coordinate with Moderna, Pfizer, Roche and other major vaccine research companies to set up a comparative trial among those staff and inmates who volunteer and who are testing negative for the virus and with negative IGG and IGM antibodies?
I think that would be a great situation from a scientific or epidemiological perspective, but there are a lot of protections from an ethical perspective around doing studies in the prison population. So I think because of these challenges, even though there's a captive audience there with disease, it will be hard to implement versus volunteers in the general population.
I've heard a lot of reports about mutations in the coronavirus and how that might be affecting the spread. Can you ask your guest to address that?
Yeah. So I think there's a lot of talk about mutations, there's this mutation that's being circulated on media. But I think right now my gut feeling is that there hasn't been great evidence for increased human transmission. There's a lot of lab evidence that this protein, this spike on COVID is a little stickier to hit the receptor. And we can use these minor differences in proteins to tell the origin of a virus. For example, this is the Europe virus, this is the Chinese virus, this came from Washington state. But beyond that, there isn't convincing evidence that it's worse or better and most importantly, I think the vaccine is going to be kind of robust because it's a relatively simple virus compared to influenza or even HIV.
San Francisco has a higher population density than the rest of the Bay Area but death rates appear higher outside of San Francisco. Why is that?
That's a great question, and I think it's multi-factorial. I think the proportion of people wearing masks in the San Francisco area, just anecdotally and me walking around, compared to other places that I visited recently like wine country seems to be higher. The population of San Francisco is generally older and the new epidemiology of this particular surge is in the younger population, kind of like the graduation, getting together, beach party kind of population. So I think San Francisco has been a little bit more protected.
Also, it's very enriched with contact tracers because the program started here, so there are a lot more per population. They can go out quickly, identify people who are infected and ask them to quarantine from others. And then finally, I think there's been a lot of initiatives to target vulnerable populations in San Francisco, like in the Bayview and in the Mission so that you not just wait for people to come and ask to be tested, you actually go out and to the community and and test the entire population.
A coworker told me that her sister-in-law is positive for COVID-19. My coworkers sees her family a couple of times a month. The last time she was around them was on June 27th. I don't work in an enclosed office with my co worker, but I've talked with her a few times from a few feet away. Should I be concerned about having my small family over for a Fourth of July barbecue?
So it depends on when she had disease. We know from studies that even though you continue to detect virus, it probably isn't alive anymore after about, I would say, six to seven days. So generally speaking, you're going to be less at risk, particularly if everyone wears masks. And try to maintain social distance, but the most important thing again is wearing masks.
If you're not really sure then definitely have as many people wear masks as possible and the longer you get away from the initial infection, the less risky that person is going to be in general. The biggest bang for the buck is the person who is infected wearing a mask, but the more people that wear a mask the better it is for the group.
And this gets to a question I've heard a lot of variations of from people who want to do some traveling, want to catch up with family, trying to figure out the best way time-wise to figure out if they're clean. In other words, when do I get a test? How do I know how long that test is valid? How safe can I feel before I plan a trip or before I go see Grandpa?
So I would see that if you can get a test and you can quarantine yourself or stay relatively safe in a bubble for about a week, we generally say two weeks of quarantine but that gives a buffer. But if you want a general time from when you can get exposed to when you develop symptoms, that's usually about a week. So you say you get a test, which is a snapshot, and you wait a week later or you feel relatively protected for a week from the rest of society in whatever way. Then I would say that time is relatively safe for you, and I would believe that you would be safe to see Grandma or Grandpa.
You mentioned a bubble, and that's in the minds of a lot of people who are trying to figure out, how do I expand my circle here and how do I verify safety? How do people maintain a safe bubble? Can you create a safe bubble without testing?
Well it's challenging, I think people already did their bubbles early on in the pandemic here in the Bay Area, and it was generally in several settings, like either in the family unit or a couple of families living in the same house on different floors. Or for child care, even essential workers I knew and healthcare workers had no choice but to make their own bubble because nobody was able to take care of the kids. So they had to go into work, so they made friends with a family. And I think if your COVID values were the same and people had generally the same ideas about how to maintain less risky behaviors, that's the original bubble.
I think in terms of expanding the bubble, I will be very cautious. Maybe do it by one or two, try to see people outdoors if you could. Those will be ways to do it in a less risky way. But certainly not having a class reunion, it's probably the ultimate un-bubble, so to speak.
(laughs) That's a good way to put it, I like that. There's a bubble and then there's the un-bubble. Okay, next question. People see a lot of numbers these days and this question asks, what defines a case of COVID? Does it mean a positive test with a person suffering from at least one symptom? Or do the numbers include people who have tested positive but are asymptomatic?
Yes, so the case definition is relatively straightforward. With COVID you have a positive RNA, or a virus test, and that's the way it counted. Certainly there are people who - because it's just a snapshot - may not turn positive for a while. There are other ways of looking at how much disease is in our community and there are very clever ways of doing it. They don't count from the public health perspective, but there are smart thermometers and citizen scientists with people calling in with the symptoms to centralized numbers so you can get a snapshot of the community. And these smart thermometers have been distributed, they kind of feed into some centralized database, and then you can see what fevers look like in the community.
And they've been used in very interesting ways. Yesterday I saw this really cool study where they show that as Bay Area residents and California residents drove more, temperatures increase in the community. It just means that you're going to increase risk by just being more mobile.
We are actually expecting to interview the CEO of one of these smart thermometer companies tomorrow morning, and it is fascinating the leading edge or early warning data that can come out of just fever. Do we know that fever is always present with COVID?
No, it definitely isn't always present, but it's a pretty good marker. I would say that at some point more than 75% of people would develop a fever as an indication that they have COVID as opposed to other kinds of respiratory infections like the common cold where fever isn't usually a feature. And of course, this time of year, the only thing going for fever is generally COVID at this time. But in the winter it'll be more challenging because, of course, influenza can also cause fevers.
Why did I just receive a disclaimer/qualifier with my negative COVID test results that asymptomatic carriers might get false negatives? How is the virus transmitted if tests cannot detect it in the transmitter?
Well I think the idea is that the virus test is just a snapshot, and it may take some time for people who have no symptoms or very mild symptoms to progress to more full-blown disease. So your negative test may be 1/4 negative, even not thinking about the test characteristics but just from the ark of the disease. And then there's a second issue, which is a test characteristic itself. It's probably about 80% sensitive for a general population. Of course in the hospital population the test is pretty good, because by the time you come to the hospital, your pre-test probability of disease is higher so the test is going to perform better.
But, you know, in the worst case scenario the test is still a pretty good test, it's just looking for fragments of the virus. But again, you may not have symptoms and you may have a negative test, but like two days later, you may get symptoms and then if you did the test again, you may be positive. But of course, statistically speaking, that's not likely in most people unless you increase your risk. So those are some nuances about the test and the disclaimer about the test.
In the United States, infections have been level or up for the last eight weeks yet deaths have steadily gone down, why is this?
Because I think the information we've been getting about this new second wavelet - because the first wave never really went away - is that it's in younger individuals, and it kind of goes around with graduation parties and the frat parties and the pledge parties and the beach situations. So in these young people, we know from data that they may get sick, but not in the same proportion as older individuals. And they certainly don't die in the same proportion as older individuals. That's the general feeling and that's what I believe myself, but others think that it's still early and you may have a lag in deaths. But there have been enough weeks of risky behaviors where we should have seen an uptick in deaths by now if it was a real uptick.
The second issue, of course, is that we've been better at treating COVID. Since the end of February to now we have remdesivir, which is an antiviral, we have convalescent plasma, we have dexamethasone, which is a steroid shown to decrease mortality. And we've been getting better at ICU care. So as long as we keep in step with the number of beds that we have available and the number of ICU beds, we're taking care of patients in a much better way.
Are Marin residents at higher risk because of the San Quentin outbreak, or is it somewhat contained?
Undeniably Marin residents are at increased risk because of the San Quentin outbreak. Prison care is public health for several reasons. There are more than 1,000 prisoners now infected and I think about 100 staff, if not more. And not everybody has been tested yet because they've run out of tests. So the reason why it affects community health is because, first of all, a lot of people in community work in the prison system - guards, concessions, administrators - and they go back and forth between the community and the prison system.
The second issue is of course, the prison doesn't have an ICU, the prison doesn't have an acute hospital. So when the prisoners get sick - and they're starting to get sick now in larger numbers - they flood the regional hospitals. So for example at UCSF, this week we admitted several prisoners because we're helping to decompress the Marin hospitals because they don't have the capacity for all of these sick prisoners.
This one kind of goes back to the mutation question from earlier but a little more specific. Do you know anything about the D614G mutation to the SARS virus?
So I don't know too much about that specific mutation to the SARS virus, if you're talking about the SARS-CoV-2 virus. If this is the gene mutation that people have been talking about recently, that's associated with increased transmission, but not necessarily increased mortality. But again, there isn't convincing human transmission data. It's all sort of like theoretical and in the lab based on a model. So I guess I would say, take caution with these laboratory pronouncements without having convincing human data.
I think really the main risk factor still is old fashioned, which is getting a bunch of mouths and noses together in close confined spaces, indoors more than outdoors.
And one last time, lay out the three W's?
The three W's: to ward off COVID-19, wear your mask, wash your hands and watch your distance.