Coronavirus (COVID-19): Press Conference with Michael Mina, 08/21/20

You’re listening to a press conference from the Harvard T.H. Chan School of Public Health with Michael Mina, assistant professor of epidemiology and a faculty member in the Center for Communicable Disease Dynamics. This call was recorded at 12:30 p.m. Eastern Time on Friday, August 21st.


MODERATOR: Dr. Mina, do you have any opening remarks?

MICHAEL MINA: No, I’ll just take questions.

MODERATOR: All right. Let’s get going. First question.

Q: Hi. Thanks for doing this. And my questions about colleges and universities, given that you’ve seen some open and then closed again after a few days or weeks on campus. Given that the WHO said this week that young adults are becoming main spreaders of this virus, do you think it’s a good idea to open colleges right now? And then what are the risks that reopening campuses poses for the cities and towns that these institutions are in?

MICHAEL MINA: That’s a great question. I’m glad the people are finally recognizing that young adults and children are spreaders. You know, we tried to publish on this months ago, back in March or something, that it’s very likely that kids are spreading the virus. We’ve been assuming that whoever we’re testing are the spreaders, and as we continue to test more and more age groups, we find out, not surprisingly, that they’re all able to spread this virus. So this, of course, gets us to your question, which is, should we be opening up schools, what risks does it pose? And I think that this is an extraordinarily complex set of questions and how each community chooses to deal with it is going to be is going to necessarily be different from other communities. So if you’re a very rural community and you have individuals coming to your college, for example, from nearby, then the risk is maybe a little bit less than if you’re a major college in the middle of a city, and that city has only a few people who are infected on any given day, but you’re bringing back people from all across the country, then you are potentially going to bring in more cases that are normally in that community. It doesn’t need to be a big city. It could be even a city of ten thousand or fifty thousand or a hundred thousand could have very low numbers. Colleges are necessarily oftentimes places where people are traveling to from all over, including places like Georgia and Texas and California and Florida, where cases continue to still be higher than in the Northeast, for example.

I think that, you know, there’s no answer that I could give. I wouldn’t want to say that it’s wrong or that it’s right to open a college. I think that the necessary components need to be put in place beforehand. And part of those, which I’ve been saying for very many months now and a lot of my colleagues have been saying it, too, is we have to stop squandering our time and we need to get surveillance systems to a place where we can actually be ready to monitor for outbreaks that might arise, in this case when students come back, and deal with them appropriately. In general, most of the country did not do this. There are some wealthy schools like Harvard and Princeton and other places that have the resources to figure out how to most appropriately deal with the surveillance efforts that are going to be needed by either creating their own labs or by working closely with with other laboratories that they have access to. But the majority of the country doesn’t have this kind of access to rapid testing at scale and so I think it’s going to prove to be very challenging, like we’re seeing at UNC and other places around the world. It’s very difficult in this moment in time in the United States to bring huge numbers of people together and assume that the cases won’t spread, especially in this age group. You know, this, I think, is one of the most difficult age groups. It’s not high school where you can realistically try to keep most people from partying. And it’s not elementary school and it’s not adults. It’s this one age group where, famously, it has a lot of people who come together on a regular basis and congregate, most likely without masks. And that’s just the reality of of college life for a lot of people. So I think it’s a very dangerous proposition. And unless you are in a very strong position to ensure you have the testing capacity, the surveillance capacity, the quarantine and isolation capacity, I’m not surprised that many schools are turning back on their initial plans to open up. \.

Q: Thank you.

MODERATOR: Next question.

Q: Yes. Dr. Mina, a lot of college football teams are planning to play this fall. I’m curious, in your mind, how possible that is to play college football? And my second question is about the saliva direct test and maybe how that impacts or helps the prospect of having a college football season?

MICHAEL MINA: Yeah. So I’ll talk a bit about the saliva direct test. We’ve seen an amazing number of misunderstandings throughout this epidemic about what scientists are saying or from the scientists themselves, not really fully understanding what they’re saying. I don’t think I’ve seen a larger media blunder and hype blunder than the saliva direct test, unfortunately. There’s no magic rapid test underlying saliva direct. It is a laboratory based PCR test that’s very, very similar to the regular CDC assay that we’ve all been struggling to scale up since March. So despite the fanfare, the saliva direct had very little to offer. It’s actually not even a test. It’s just a protocol for clinical laboratories, if they exist, to just change their PCR recipe, if you will, and only slightly, and to use saliva instead of an entering air swab. But I personally think that a q tip in the front of your nose is just as easy as spitting into a tube. So in short, it’s not a rapid test. It’s still a laboratory based test that will be prone to the same massive delays as any other test that’s existed. It is perplexing to me how this was so incorrectly covered. And the fact checking on it, was just astounding to me because there is literally just a protocol, it’s a PCR protocol and it still needs to be done in a high complexity clinical laboratory like lab for Quest, and it’s not adding a new product to the market. It’s literally just saying this is how you can maybe slightly, change your PCR test. It’s not decreasing cost much at all. And I think the misconception overall was that it be cheap. But we have to realize that all of the costs that’s going into these PCR tests is across the country already, it’s pretty much just markup. It doesn’t actually cost one hundred dollars to do a PCR test. We do it in our laboratories all the time for six dollars apiece. So the companies are just marking it up, which is where the price comes from. And that’s sometimes to cover actual costs of the manufacturing of the robots and things like that. So I can answer more questions about that. But I’ll stop there and just say the saliva direct is a marginal which allows saliva, which there’s already some acids that do in it. And it did remove an RNA extraction step, which if you’re already doing the CDC assay, there were already plenty of ways to do that stuff for very cheap and very quick already. So I’m perplexed at the intrigue of the saliva direct. Maybe it has a nice name and it worked with the NBA to create a protocol that, frankly, any lab was already thinking about, but not using force for good reasons.

So that’s that, I think when it comes to your question of football, I have really struggled throughout this epidemic to know where to take off my infectious disease epidemiology hat and my medical hat and put on it more of an economics or a social society kind of hat and recognize that there are tradeoffs. The only metric to evaluate here is not necessarily numbers of cases and deaths from the coronavirus itself. It’s all of the ramifications that come with turning off major systems, whether that’s closing the whole economy or closing down the NFL. There are a lot of people who rely on working for the NFL, for example, for their livelihood. And I don’t mean the coaches. The coaches are going to be fine. The players are going to be fine. I mean, all the staff who maybe get paid minimum wage. And this is just a microcosm of the much larger system of questions that we’re thinking about, which is where does the balance lie? At what point are we doing more harm than good? I think so far the epidemic and the viral spread has certainly been taking priority for a good reason. But, you know, I think that all of these decisions we would make, whether football players should go back, I don’t know. I mean, should football players go back knowing all of the risks that they might have? You know, they these are people who are not necessarily in an age bracket where hospitalization and mortality is likely. They’re potentially able to be bubbled in with each other like the NBA is doing. And there’s a lot of people who rely on their livelihood to kind of cater to these games going forward. And so I would not recommend that fans go back into the stadiums. That would be a disaster. But if the football players want to play football and put it on TV, I think it’s not the end of the world.

MODERATOR: Do you have a follow up question?

Q: No, I’m good. Thank you very much.

MODERATOR: Next question.

Q: Hi. Thanks again for doing this. I was wondering if you could talk a little bit about unnecessary quarantines related to PCR testing. Do you have any sense of how many people were forcing  out of the world because of this?

MICHAEL MINA: Yeah, it’s a great question. I tweeted a lot about this last night and so the background for anyone who is listening is the PCR test remained positive for a very long time, potentially after somebody has actually been truly positive with the virus. And that’s just because the RNA from the virus can stick around in somebody’s mouth or nose for weeks, if not, even like a month or two. As the CDC recommends and as we know, most people are no longer transmitting the virus after, say, a week or so post symptom onset to a point where the CDC actually recommends that people leave quarantine after 10 days of symptom onset and then don’t go and get tested again later because the test will likely be positive.

So the problem with all of this is that if somebody gets a PCR test for the first time through some screening mechanism, not because they’re symptomatic, it’s actually more likely than not that if that PCR test is positive, that they have already recovered from their infection and they’re transmissible period, and they are no longer infectious, but their PCR is just remaining positive. In the same way, a piece of hair with somebody’s DNA on it can remain in a room far longer than the person. You know what way after the person leaves the room, you can still pick up their DNA. It’s the same thing, this virus can leave the person no longer infectious, but the RNA will still get picked up. And so what this means is that if you’re infectious for one week, but then your PCR positive for five weeks afterwards, then for five out of the six weeks that you’re positive you will potentially be, for public health purposes, a false positive on PCR. And that means that if that is the first time we’re testing somebody through surveillance and it’s an asymptomatic person, then your probability of testing them at any one of those six weeks is kind of equal. And so you’re more likely to detect them after they’ve been infectious. But we’re treating all of those positive results that we get in that post infectious period. If it’s the first test we’re getting from that person, then we’re treating it as though they were just infected yesterday, for example, or a week. And we’re asking them to quarantine for 10 days. Meanwhile, they’re noninfectious. And the travesty is that we’re spending so much time focusing on capturing people over here by mistake that we’re missing the people who are actually infecting. And those are the people who we should really be quarantining at any given time.

My expectation is that actually in places in the country like New York and Massachusetts, where cases are pretty low. But, you know, even with low cases, we’re still finding hundreds, thousands of individuals who are positive. And across the country, we found millions of people who are positives, probably my estimate is that it could be as much as half of them or more of these millions have been potentially quarantined despite having been already recovered from the virus. And so I think in a low incidence place, it could be the majority of people who are getting detected through infrequent surveillance testing are actually probably erroneously being quarantined. And then the contact tracers are erroneously tracing the wrong contacts because they’re then saying, OK, well, this person just turned positive that the swab taken two days ago, let’s track their contacts over the last four days. But really, if they really wanted to track the actual context that happened, they would have to go back a week or two or three or four or five. And that’s pointless anyway, because those people have already recovered, too. So we’re spending all this time surveying and contact tracing. And we’re using the wrong tool to do this surveillance, we’re using this tool that remains positive long after people are infectious. And it’s one of the reasons this deficiency of PCR tests, which really hasn’t been well explained to the public, and frankly, most physicians don’t understand it in general because most people don’t look at what the positive actually means. They just assume that a positive means positive for infection. And it’s one of the reasons why I’ve been really pushing for tests that will really only turn positive when people are actually infectious and can be used very frequently so that you’re much more likely to get somebody the first time when they’re at the beginning of their infection and not after it’s already passed. And so I believe that probably a majority of people that we’re quarantining are probably not infectious at the time, we asked them to go into quarantine.

Q: Thank you.

MODERATOR: Next question.

Q: Hi. Thanks for taking the question, Dr. Mina, I appreciate it. So my question is about Miami-Dade, Florida, and I don’t expect that you’ll be familiar with conditions on the ground here. But we’re a hotspot and we’re still in the earliest phase of the state’s reopening plan with some additional restrictions imposed by the mayor, like an ordinance mandating that people wear a face mask in public. There’s also a ban on indoor dining at restaurants. But there’s pressure now from businesses and others from Miami-Dade to reopen further, as most of Florida’s other counties have done, and the mayor is starting to contemplate that. So my question is, what are the indicators that we should be looking for, that it’s safe to resume indoor dining or even reopen casinos and bars, even at partial capacity? And what are the preventive components that need to be in place to ensure that we don’t go back to where we were in June and July?

MICHAEL MINA: Well, I think the first thing is, you know, you started out by saying that you’re a hot spot. Just the notion that if you still have so many cases that you would, that you feel the need to say that Miami-Dade is a hot spot still, that is an indication not to open up at all. I think if any place is still a hot spot, the only tool that we have at our disposal right now is to continue it really very aggressively social distancing and not opening up. And this is the problem. You know, if we keep dancing around this middle area, we’re not going to get anywhere. We’re not going to know. Cases will continue. This is a very transmissible virus. And pseudo closing down isn’t going to take a hotspot and get it to one case or two cases per hundred thousand populous. What we really would like to see is for cases to get down to numbers that are generally manageable. And by manageable, I mean that we can realistically deal with both the hospitalizations and we can deal with the contact tracing. It’s going to be a part of the effort that we can do that appropriately. And so part of that is making sure that the right testing is up and available to even detect who’s positive that you can stop the transmission chains. Which generally isn’t working anywhere in the country. And so that leaves us either with tools that aren’t yet approved that I’ve been talking a lot about in media, but otherwise it leaves us with keeping things shut down in a place like Miami-Dade. And I think that until cases get so low that that actually that life for the average person walking around is pretty safe. You still want to have everyone wearing masks and social distancing, but you really probably should be aiming to get cases out like a couple of hundred thousand populace as a way to ensure that if new outbreaks are do start to emerge, that you can actually you have the resources, the bandwidth to go and tackle those outbreaks and maybe close down small sectors of the environment to stop this community’s outbreak. But you have to have a lot of bandwidth to do these really sort of pointed activities and aggressive maneuvers in certain locations. And so until you get everything under control, that bandwidth just doesn’t exist really in general. So I would strongly advise us if there is still a lot of cases going on, then it’s just not the right time to open up. You probably want to want to keep suppressing cases as much as possible before giving them a chance to increase again.

Q: And I if I can follow up. I may have misspoken when I said a hot spot. But for sure, I mean, our hospitalizations have been declining for weeks now. We do have fewer cases, but we’re still at, according to the Florida Department of Health, about a nine and a half percent positivity rate for new cases. And we do still have the most cases of any other county. But it sounds like what you’re saying is that, you know, even if it’s not technically a hotspot, we want to get it down to those couple cases per hundred thousand people and have that infrastructure that it doesn’t sound like anybody has yet.

MICHAEL MINA: I think that there are some places that have done a good job at getting cases down to a much more manageable number. New York City has gotten cases to be very low. Part of that might be due to so many cases early on that they actually have gotten some herd immunity built up. But I’m just looking at Florida right now and there’s still huge numbers. Just looking at the graph, it’s still pretty high numbers, 4000, almost 5000 cases in Florida. So the state as a whole really has to be much more aggressive. If Miami-Dade were to get this thing under control and then open up, there’s so many other cases happening around the state overall that very quickly those will flood into Miami-Dade and you’ll end up seeing major outbreaks again. That’s just a microcosm. I say the same thing about the whole country. You know, if Massachusetts and New York wants to really open up and bring students back or whatever might be, we need to make sure that cases are very low in Florida because we will be bringing students back to Florida. So I think that it’s really incumbent upon all of us and wherever we are in the states to just really do whatever we need to do. And right now, that whatever we need to do is unfortunately, keeping the economy closed down for longer. It comes at great peril and great expense to the constituents of these states, which means that either the federal government or state governments have to kick in and really fund, and make sure that people aren’t going hungry and and have relief packages that are actually reasonable. Short of it though we’re gonna keep living and dancing around this middle ground where cases continue to burn, people continue to die. And the economy continues to waffle about whether or not it’s opening and the middle ground is kind of the worst place to be. It’s kind of a stew. Pull the Band-Aid off quickly and kind of shut everything down and get cases to a very reasonable number everywhere. Something like Osterholm has advocated for, and I don’t disagree with. I do for other reasons think that there are many other options or there’s a couple of other options to go along with that through a very different type of testing mechanism to get cases down. But in general, you’re not alone, unfortunately, in Miami-Dade, and grappling with this question, a lot of the country remains too.

Q: Thank you, Doctor, I appreciate it.

MODERATOR: Next question.

Q: Hi, Dr. Mina, thanks again for the press briefing. This question is almost a two parter, if you’ll forgive me for that. I’m sure you’re aware of the announcement by HHS the other day that they were forcing FDA back on this business of any pre market notification requirements for lab developed tests. If I had to guess, I would guess that you don’t see that as a game changer, if you’ll pardon the cliche, given that you still have to deliver a sample, run a through PCR and all that sort of thing. But I would like to get your feedback on, to what extent this assists the situation. But more importantly, I think is how that was received by you and other epidemiologists who’ve been watching this. I’m not asking you to comment on the politics behind it, but just how it was received by you and other epidemiologists keeping track of the situation all these months.

MICHAEL MINA: Well, clarify that question, because that that decision is far from an epidemiological decision. I’m also a pathologist. I’m an epidemiologist, an immunologist, but I also run clinical laboratories as a pathologist. And the reason I say that is because I think there’s been a lot of confusion about who plays what roles during this epidemic. And so the question is a really good one. It is fully a very nuanced, laboratory based question that actually we’ll have pretty much no bearing on the epidemics or the epidemiology or anything, the epidemiologists who are not also pathologists, think about. So what that HHS decision was, was essentially the reason why it doesn’t change much is because it only affects CLIA laboratories, first of all. It doesn’t mean that any company can just go and start making tests and distribute them. Doesn’t mean that Roche an Abbott can come up with some new cheaper tests and just start producing it immediately or something like that. It doesn’t mean any of that. All it means is that a clinical laboratory that is run by a medical director like myself, is allowed to once again do what we normally do. And that is that normally, if I want to create a test and use it for my patients in my hospital, I am allowed to do that. I’m a physician. It’s part of the practice of medicine. I don’t put my stuff the scope on people anymore. But what I do is I help design and develop the tests that can help diagnose those people. And so this is what is defined as a laboratory blood test. And under normal circumstances, I can develop whatever test I want, if I want to make a new flu test for Lyme disease tests or cholesterol tests. I’m allowed to do that, use it in my hospital as a laboratory, develop test. That’s a technical term. And I don’t have to go through the FDA when they emerge.

When the public health emergency was announced by HHS back in January. It kicked into effect this requirement of an emergency use authorization for any laboratory developed test or any coronavirus just for that matter, whether it’s point of care or made by a manufacturer or developed in a laboratory. And so this means well, and the reason it means well is if this was Ebola, for example, then the cost of getting a test wrong, whether positive or negative, is extreme. If you give somebody a false positive in Boston and say they have Ebola, that would throw everyone into a huge frenzy and cause a disaster, and if you tell somebody their falsely negative, that would lead to Ebola spreading in the community. So from a pandemic perspective for something like that, it makes sense to have a really tight regulation over new tests that are going to be developed to respond to a public health emergency in this case. This is a coronavirus that spreads very quickly. So all the FDA emergency use authorization did, by removing my ability as a laboratory director to make a lab develop tests, was kind of handcuff us early on and allow it.

We actually had tests that were that were working very well back in February that we weren’t allowed to use on our patients because the FDA put this EUA application process into effect. What happened was because they decided that they wanted everyone who wants to develop a laboratory, developed tests to go through the FDA. They became extraordinarily inundated with requests. And this isn’t surprising. There’s a lot of clear labs that can do PCR. And so a lot of clear labs, clinical laboratories decided that they were going to, of course, start performing PCR tests for coronavirus for their patients. But because every single one of those physicians or laboratory directors had to create an application that went to the FDA despite knowing very well how to do a PCR. It just slowed everything down. So then the FDA said, OK, there’s no way we can we can get to all of these applications and it’s already the end of March, early April. And this virus is getting completely out of control because we’re not allowing tests to be run, that the FDA took an extraordinary step and said, look, we still require the EUA program and we still require labs to use to apply for authorization. But, you know, we’re so bogged down and backed up that just submit your application and we’ll get back to you in a few months. And that’s pretty much what happened. So very quickly. It almost became a joke that a lot of places have been running coronavirus tests in their lab as lab developed tests without any way approval just by saying that they have the applications submitted. So it really started to lose meaning.

Overall, now that this executive order has essentially removed the requirement for an EUA, it was based actually more on legal grounds and politics versus what I would consider the good reasons for removing it. I do think it was a good decision, and I think it’s a good decision because frankly, if you’re a CLIA laboratory director, a physician or there are some PHDs who are also clinical laboratory directors, you should feel like you need to create the very best test you can and ensure that people are getting good quality. You’re not going to go and create a terrible test any way that requires FDA oversight. The concern now is with the FDA approval removed, there is such demand for this that I worry that everyone with a medical license and who’s never done PCR in their life might see some money here and could go and just start up a CLIA lab, get their CLIA certificate approved in their state or by CMS and then start doing PCR without really understanding the limitations of it and sort of how to do it properly. So I’m a little bit worried that now when there’s money on the table, like there is potential for something like coronavirus diagnostics. Even good, well-meaning physicians might go awry. And so that’s the one danger. But I think in general, it’s a good decision to remove this erroneous or this onerous stuff that really isn’t usually there for CLIA labs anyway.

Q: If I may just add a little follow on here. Does it affect your perception of how FDA’s institutional impulses, for one, for a more neutral term in the eyes of the medical community, and I am asking you to kind of go on the record with something could be controversial. Is this an indictment of FDA that comes as no surprise to you all or, you know, is this something that is a little bit of shock value for some in the testing community?

MICHAEL MINA: I would say that in the testing community, it’s not shocking. I think generally, for people who are normally running clinical laboratories, the handcuffing of labs to require an EUA application was seen as unnecessary, I would say by most in the laboratory community. It is an extra safeguard to a certain extent. But patients don’t normally ask or question if they go to a hospital. They’re not normally questioning the quality of the tests that the pathology department is producing. That’s why you go. That’s frankly why there are some good hospitals, bad hospitals. You know, there’s different qualities. But in general, that’s all part of going to different types of hospitals and getting tested. And unfortunately, it’s also part of inequity in resources and things like that. So I wouldn’t say this is surprising or a shock. I think that it’s a relief for people who do direct CLIA labs that, you know, that it was seen as onerous and unnecessary at the beginning. And now I think that it’s just kind of putting things back to normal. I wouldn’t say that it’s not dinging the FDA in this case. The FDA has already been dinged enough by that just the roll out of the EUA process and the fact that the United States had no testing for the first two months of this epidemic, if not three months, and really barely any for months after that, has done enough damage to the credibility of the FDA to make sure that these things were happening optimally. This is just kind of a welcome change back to normalcy.

Q: Thank you very much. I appreciate it.

MODERATOR: Next question.

Q: Dr. Mina, thanks for taking two questions from our newspaper here. We’ve been covering antigen testing down in Florida. The state of Florida has actually started using the Quidel tests. Obviously, as you as you stated earlier, they are not a rapid test, but some say that they’ve been able to turn around quicker than the PCR tests, and they’ve also done a lot of decentralizing of labs. One issue that’s come up here is kind of the way they’re using the antigen. If you’re ages 5 to 65, you need to have symptoms. If you’re 65 or older, you could be asymptomatic or symptomatic and get the antigen test. But some public health experts here have said that they should not be giving people negative antigen results. So they should be PCR confirming negatives and collecting two samples to do that. And that’s something that county is considering right now but hasn’t hasn’t done. I was wondering if you had a viewpoint on that.

MICHAEL MINA: So it really depends on what the purpose is of the test. And so if you’re using it first for diagnosing sick people or people who are high suspicion for being infected, then then probably use a PCR test. If you’re truly diagnostic doing diagnostic tests and it’s like in your doctor and that’s your patient, then use the the most sensitive tests because you’re not really worried that you’re catching people. You know, it’s not a surveillance program. But if you’re just getting a certain asymptomatic screening of people coming through a drive through, for example, or something like that, then I would actually say that the Quidel test is fully appropriate. Again, people are assuming that these things have terrible sensitivity, but that’s only because, like I mentioned earlier, there are weeks that go by after infection that people don’t actually have the virus, but just show the RNA. And so that makes the antigen, if you take any of those samples, when people are PCR positive, they will be negative on an antigen test, like a Quidel test. But it doesn’t mean that the Quidel test actually has that part of a sensitivity when people are infectious and when it matters. It just means that the Quidel test isn’t catching people after they have been infected. In the same way, that if you have a person detector and you have a camera and that camera can detect people, but you also have a PCR instrument that could detect people’s DNA. Well, after the person leaves the room, the camera’s no longer going to detect that person. But the PCR test could still detect that person’s DNA was left in the room. A piece of hair or something. So I wouldn’t say that that means the camera’s wrong. There’s actually no person there anymore.

So this has been a huge misconception about the sensitivity of antigen tests. They can actually be tests like the Quidel test can actually be very good to detect somebody when it matters. And for a lot of these drive through sort of surveillance tests, that’s really all that matters. I would say we shouldn’t necessarily be spending our time getting a second swab and clogging up the diagnostic pipelines by running PCR tests on all the negatives, because if you do see a discordance between them, the vast majority of time it’s going to mean that that person has already recovered and the PCR test is just detecting what was there before. And so it’s not even an actionable result anyway. So let the person go along their livelihood. It’s already been weeks maybe since they were infectious at that point. So I don’t agree. I would say that public health agencies have been confused about this point. The FDA has been confused about this point. CDC has, pretty much everyone has been confused about this point. They’re failing to see that the biology underlying the metrics of these tests and this is an unfortunate thing that’s kind of emerged with this pandemic.

Q: Just a quick follow up. We know we also spoke to the public hospital here in Miami, Jackson Health System, which has been using the BD antigen tests, and they’re using it in kind of an odd way. They’re testing every symptomatic emergency room visitor and they’re swabbing them all, and you get a PCR test regardless of whether you get the BD, but they’re testing all the symptomatic emergency room visitors for COVID. And they view it as a good result. But it kind of struck us as a little low, they said about 70 percent positive agreement with the PCR. And the reason I thought it might be higher was just because they’re symptomatic E.R. patients. Do you have any thoughts on that? I mean, is it possible to have low viral loads even if you’re hospitalized? I know that sometimes the clinical course of this disease, what you’re experiencing is more of an inflammatory response than than really a viral load issue. So do you think that that could be part of that?

MICHAEL MINA: Absolutely. And by the time a lot of the people get to the emergency room with a virus like this, again, this is an Ebola something, this is a virus that a lot of people can withstand the symptoms for quite a few days before they say, OK, I should go check myself out at the emergency room. So I think that it’s really important, exactly what you said. And the other bit is, I think from a true diagnostic perspective, I think that, again, where you’re a physician and you want all the shreds of evidence, you can get to understand what’s going on with your patient, then PCR is absolutely the way to go. If you have a very high suspicion that this person is positive, then use the most sensitive tests, because if it’s a one off kind of thing if they did get over their infection two weeks ago and they actually have something else now, it could throw you off. Actually, if somebody has flu and they had COVID three weeks ago, they might still be COVID positive for PCR. So there actually are some issues there. But in general, that would be rare occasion. So I look at the antigen tests like Quidel’s and Sofia’s. And what I would like to see are really rapid paper strip tests that can be used daily by everyone. I try not to call them true diagnostics, even though Quidel and BD have a diagnostic claim. I think that they’re totally reasonable to have that claim. But I look at them as transmission indicators more than anything else versus a diagnostic. And so you can be sick with this virus and have all the virus in your gut. It’s actually a virus that really likes the gut, which is why it shows up so much in school and sewage water and so you can be sick with the virus and not be transmitted, not have a lot of virus in your nose, your saliva in your mouth. And that’s where PCR would really shine because it would do a better job at finding people who are acutely ill but maybe don’t have a lot of virus in their nose. And so that’s why I like to think of the antigen tests as tests that really shine at finding people who are most likely to be transmitting. So those people that are feeling ill or not, if they have enough virus sort of in their respiratory track to actually spread it to other people, these tests will term positives as a diagnostic. I think that they do have their limitations compared to PCR, it’s just a superior diagnostic. Absolutely.

Q: Thank you so much for those responses. And last thing, just really quickly, because you brought it up earlier, partial herd immunity. We looked at that here in Miami. Youyang Gu estimated nearly a third of Miami-Dade County has already been infected, which we thought was a really high estimate. And we kind of had varying opinions from very smart people like Marc Lipsitch and Bill Hanage, kind of how to how to read that. I never saw your opinion on partial herd immunity and how that could be playing a role in what we’re seeing in communities with that level of exposure.

MICHAEL MINA: I often liken herd immunity to regular immunity. These are not binary things. These are  in the same way that a viral load is not binary. It’s not on or off. Immunity is not binary. It’s not on or off. And herd immunity is not binary. Partial herd immunity goes a huge way to dropping the effective rate of the virus since it’s slowing spread. If you’re not achieving herd immunity, then it could be that spread can continue but slower. And that was actually the whole idea when we talked earlier on about flattening the curve. You want spread to slow and slow, if you can achieve a partial herd immunity to the extent that it slows the spread just by creating fewer and fewer susceptible people, eventually you’ll achieve herd immunity, which is defined as the threshold and immune status. You have to get to a population level where the virus will not persist sort of indefinitely and where it’s actually declining and declining. And so partial herd immunity is absolutely crucial to bank on. And it’s no different, for example, than let’s say you have 10 people in your house and and seven of them are immune, then that would probably give you full of herd immunity and maybe the virus will just be unlikely to bump into those other three people and spread to them. And so there won’t be any new transmission or maybe one of them will get infected, but it will go beyond that. If only three of them come over and they’re already immune. Well, that’s three less people who have the potential to participate in the transmission chain. And so that’s partial herd immunity. And absolutely it’s crucial.

Q: Thank you so much. I appreciate it.


MODERATOR: Next question.

Q: Hi, Professor Mina. Thanks for doing this call. I have two questions. First, is a quick one. In L.A. and I think Delaware and maybe the Air Force and maybe others are doing these mouth swabs. I was just wondering if there’s been any science that shows whether they’re just as good as the other kinds of swabs for PCR testing.

MICHAEL MINA: Oh, you mean the cheek swabs and things like that?

Q: Yeah, the cheek swabs. For a while there was a little bit of skepticism about them, but they’d been continue to use them. I just wondered if there was any efficacy data on them.

MICHAEL MINA: Yeah. So to be honest, it’s one motive collection that I’ve seen very limited evidence for. And I actually haven’t seen any really compelling evidence, one or the other, in terms of how well they are truly working compared to other an entering air or saliva test. My hunch is that based on the biology and where the virus grows, that it’s potentially less likely to catch. You know, it might be an inferior collection system compared to the nose, but it’s hard to say to saliva, will be, if you have a good amount of virus in your saliva, then it’s going to get off your cheeks as well. And so I want to see some more data before I really comment it one way or the other.

Q: Other question, you know, the vaccine trials have been sort of packed to focus on areas where there’s high transmission. At the same time, these areas are starting to have higher levels of immunity in the population. I just wondered if at this point, have you thought, as everybody thought about how that might affect the data that comes in in terms of the amount of time it will take to get results that are meaningful? In other words, if you have higher levels of preexisting immunity and both the placebo and vaccine groups, it seems like you’re going to have fewer cases. 

MICHAEL MINA: In fact, Marc Lipsitch and I and a PHD student in our department, we published a paper in Nature Medicine on exactly this issue quite a few months ago. And essentially, we said that we should be using serology tests before and after vaccine studies to better interpret the efficacy of the vaccines and to power them more appropriately because of these particular issues that you’re raising. So if you have a herd immunity that’s built up on both sides, then certainly it’s going to be harder to see an effect. And if you’re not recognizing, if you’re just assuming everyone susceptible, invariably, then that could be a huge mistake for the power of the study and the speed that you anticipate that the study will take before you get good results. So this is a really crucial piece. And that it is why we go for trying to find plate hot spots to do vaccine studies, because it’s certainly the quickest way to get a vaccine study done. And so if you were to go in to places that are quickly accruing herd immunity, not only do you run the risk of obscuring your results and maybe either getting mixed messages and blurring what was the vaccine effect and what was the herd immunity effect or the national infection effect that maybe went undetected. So this is a very important piece. And certainly it will extend the time of the vaccine studies if communities start to achieve levels of herd immunity.

Q: Mm hmm. Could I ask you one other thing? I haven’t been focusing that much on testing. I mean, it just sounds like the in terms of stopping the spread of the disease, these antigen tests, you would want them to be there to be more of them out there. I don’t hear about their availability much. It doesn’t seem like they’re so good at being used routinely. Do you have thoughts about that, or is there a problem with producing them?

MICHAEL MINA: No, they’re still illegal, they’re not FDA approved because they don’t live up to the FDA approval and thresholds for diagnostic tests. They exist, though. I’m starting to talk to the companies and just saying, look, can we start just producing hundreds of thousands or millions of them and getting them used, you know, skirting the line essentially between I don’t want to go against FDA regulations and get the company shut down or me lose my medical license or anything like that. So are there ways to use these in pilot studies in in New York City schools or something like that to try to look at their efficacy, but truly do it as some sort of, like, surveillance mechanism?

Q: Is it illegal for a hospital to to produce the hospital lab to produce them and distribute them as long as they don’t say these are diagnostic tests?

MICHAEL MINA: Well, that’s the hard part, is that I can say that they’re non diagnostic transmission indicating tests. And that’s what I think of them as, non diagnostic transmission indicators. And I want them to be deemed as such. But the FDA and CMS have a pretty broad definition of what constitutes a diagnostic test in our country. And it’s pretty much any biological test that will give somebody information about themselves that could cause them to change their behavior is considered to be a diagnostic test and therefore regulate it, if it’s a lab based, tightly regulated and otherwise FDA.

Q: So, I mean, is there pressure on the FDA to do something about this, to make it? I mean, where’s that in terms of the policy making?

MICHAEL MINA: Yeah. Every day I’m talking to – I’m getting texts right now – to governors and senators and congressmen. And they’re writing letters to the FDA. So this is moving. There’s a lot of pressure from all walks of life right now trying to get these things approved and get the FDA to budget on this particular issue. And so I think that t’s hard because the FDA only has one lens, and that’s a lens of looking at diagnostic assays as a medical diagnostic. And so to do this, they need to create a new pathway for exactly 18 tools, which in this case would be regulating public health tools, which they don’t consider that part of their mandate.

Q: Are rich and powerful people already using these tests?

MICHAEL MINA: They’re not because the companies aren’t making them. Some of the rich and powerful are able to get their hands on a BD or things like that, maybe, but otherwise, I would say no. They are getting their hands on maybe some of them. There are some available internationally. So they might be ordering them from South Korea and stuff. And they’re pretty cheap and they’re good. So I would say that the ones that rich and powerful people are using, like there’s some New York Times article recently about it. These are already FDA approved diagnostic tests, so they’re probably actually acquiring medical professionals that come to the door and test people with a diagnostic test before entering.

Q: Right. Thank you.

MICHAEL MINA: Sure. OK, well, I have to run then and get on to yet another call. But thanks everyone for joining.

This concludes the August 21st press conference.

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