Michael Mina: Why do we still need rapid tests?

Discussing the use of rapid tests to protect the public health—with epidemiologist and immunologist Michael Mina.



Why do we still need rapid tests? Epidemiologist and immunologist Michael Mina discusses the use of rapid tests as public health tools. Topics include using rapid tests to protect gatherings of friends and family; the differences between rapid tests and PCR tests; and why rapid tests are useful even for people who are vaccinated—particularly the elderly. Mina’s advocacy for rapid tests has been covered extensively in the pages of Harvard Magazine in “Failing the Coronavirus-Testing Test,” “Will Congress Fix the Testing Debacle,” and “Rapid Tests, In Time for Fall Surge.”  


A transcript from the interview (the following was prepared by a machine algorithm, and may not perfectly reflect the audio file of the interview):


Jonathan Shaw: How good are rapid tests—the kind that can be bought at a local pharmacy—at detecting infection with the novel coronavirus? Could they be useful this holiday season for protecting elderly relatives, friends, and other loved ones, including those who are already vaccinated? And why is there a shortage of these tests in the United States but not in many other developed countries? Welcome to the Harvard Magazine podcast, Ask a Harvard Professor. I'm Jonathan Shaw. During today's office hours, we'll speak with Michael Mina, an assistant professor of epidemiology at the Harvard T.H. Chan School of Public Health, and a core member of its Center for Communicable Disease Dynamics. Dr. Mina is furthermore an assistant professor in immunology and infectious diseases at the school, and associate medical director in clinical microbiology—that is molecular diagnostics—in the department of pathology at Brigham and Women's Hospital, Harvard Medical School. As part of his advocacy for broader availability and use of affordable rapid tests to fight the ongoing pandemic, he has worked with regulatory agencies and elected officials alike—the aim: to get people safely back to work, school, and all their other pre-pandemic routines. Welcome, Professor Mina.

Michael Mina: Well, thank you very much. I'm very happy to be here.

Jonathan Shaw: Your expertise straddles the worlds of immunology and testing. Why when we have vaccines do we still need rapid tests?

Michael Mina: This is a really terrific question. Unfortunately, what we are finding, which isn't very surprising, is that the vaccines, despite our great hopes around them, just aren't actually performing as well as we had hoped to stop transmission. I want to be very clear that the greatest benefit, and the greatest thing we could ask for of a vaccine, is that they stop people from going to the hospital. And so they're doing a really good job at that. And that's through driving a good immunological memory response that allows people to be protected, but the type of memory response, the type of immune response that people gain from the vaccine is turning out not to be very good at stopping transmission of Delta, and that's this new variant, and probably won't be very good at stopping future variants from transmitting. It helps don't get me wrong. But the nice thing about testing is it's a complement, not a substitute in any way, shape, or form. But it is a compliment to vaccination, to help people identify in real time, when it matters, that they're infectious, and can allow them to stop their transmission chain from infecting others. This is extraordinarily important today. As we look at schools and businesses, nobody wants to shut down again. And I think it's fair to say that nobody will shut down again in any real way. But quarantines are still commonplace, especially in schools. One child is infected in a classroom and sometimes 10 or 15 other kids have to go and stay home for 10 days or 14 days. The only reason quarantines exist is because of an information problem that we don't know who is infected and infectious. Rapid tests enable us to know that information in a timeframe that is important, which is almost immediately, and therefore we can actually create programs even in the midst of vaccination campaigns. We can create rapid test programs that keep people in school, keep people at work, and essentially get rid of the need for these onerous quarantines as a control measure.

Jonathan Shaw: With the coming holiday and winter season, the risk of indoor transmission rises. Could rapid tests help prevent surges as families gather for Thanksgiving and the ensuing holidays?

Michael Mina: Absolutely. This is the wonderful thing about rapid tests is they are very good at answering the question, “Am I infectious now?” And because they're very good at answering that question, because they can be scaled and made accessible to Americans and to people across the globe, they can be very, very useful for people to be able to use before they go to their family's home. Somebody like me, I'm coming from a city. If I go to my family's home, or my wife's family's home in rural area, you know, maybe I'm at a higher risk of exposure. And at her family, there are people in their 90s. So I don't want to mistakenly bring COVID to them. And especially since I have a little kid, I'm going to the pediatrician a lot, I'm a high-risk person for exposure now. And if I want to be as careful as possible, then it's very simple. The moment, you know, the day that I'm going to go and have dinner with that family, I just use a rapid test early in the day. And if I'm if I'm negative, then I'm very, very unlikely to be infected and infectious. And if I'm positive then I'm very very likely to potentially be a risk to other people. And so these tests are very simple, they take around 30 seconds to use in terms of hands-on time. You could use a test in the morning, go drink your coffee, come back 10 minutes later, and get a result. And it can be a very powerful tool to allow people to feel empowered to not be a vector of transmission.

Jonathan Shaw: Last fall, in a conversation convened at Harvard, Anthony Fauci was asked if he had any regrets about the way the U.S. pandemic response was handled. He said, he wished he had advocated sooner for rapid tests. When did you first realize that rapid tests could be a powerful means of controlling the pandemic?

Michael Mina: I realized it in about March of 2020. And that was because in January and February, I was working very hard to get PCR laboratories started. At Brigham and Women's Hospital, I was trying to get buy-in from the hospital leadership to start a COVID test program for PCR there. That ran into some early hurdles, because it wasn't seen as a priority test by the leadership of the hospital. It was still a foreign virus, you know, to many. And so as a result of the slow rollout in the hospital of getting that test started, I went to the Broad Institute, and I started a major testing operation at the Broad, which now has maybe the highest volume or highest throughput laboratory in the country, for COVID testing. But even with all of that effort, and with all of the PCR testing, we were getting going, it became extremely apparent that A: there wasn't going to be enough. And the turnaround time wasn't going to be fast enough, that this model that we did at the Broad couldn't easily be replicated, you know, 300 times across the country or more. And it also occurred to me that I had a conversation with a local manufacturer of these rapid tests. They're a startup called E25Bio, they're spun out of MIT and Harvard, I believe, and I was talking to the CEO, and I said, “This is great.” And he said, “We do have a COVID test. It's a paper strip. But the problem is, it's not sensitive enough, and it's not going to meet the bar of PCR.” And I very quickly just said, “It doesn't need to be sensitive enough, you know, it doesn't need to achieve the same sensitivity as PCR, because we're just interested in identifying those people who are most at risk for spreading, which, if that's your goal, then you just need to have, you just need a test that's going to detect a million viral copies, not one.” And so that's really where all of this started, it was this one conversation with E25Bio and hearing him say, our test just isn't sensitive enough for what the FDA is going to ask for. And that really started that led to a whole series of mathematical modeling, epidemiology papers, and research, and then later on advocacy—to try to get people to understand that there are different forms and different reasons for testing. And they don't all have the same metrics behind them.

Jonathan Shaw: That leads very nicely into my next question: why is a rapid test technologically and logistically a great public health tool and a lousy hospital diagnostic? And why is a PCR, or molecular test, great for use in a hospital setting and lousy as a public health tool?

Michael Mina: This is another terrific question. And one that has led to so much confusion. When we look at what we want in a medical diagnostic test that might be used in a hospital, as a physician, I'm maybe taking the role of more of like a detective. And so I want all of the evidence that I can get when a patient comes to me and says, “Hey, Doc, I'm not feeling well, I haven't been feeling well for a few weeks. Do you think this is COVID?” Well, for that question, I'm interested in that one person. I'm not interested in that person's family, or the people that that person was on the bus with this morning. I'm interested in that one person and being able to answer the question, do you now or have you recently had COVID that led to some of your symptoms? And for that, I want a very, very sensitive test. And I don't really care about the timing of it. If it takes 24 hours or 48 hours, that's fine, I can tell the patient, you know, don't worry about it, go home, or if you're really sick, be admitted to the hospital. And we're going to get you the result, you know, as soon as we can, but you're no longer a risk to other people, because we're now all having this conversation and you can go and quarantine until you get your result. But that is not an appropriate perspective for public health. Because for public health, you can't have 300 million physicians working with 300 million people in this country. And our questions are different for public health. The question is not, “Do I have any remnants of virus in me that suggests that my symptoms last week are from COVID?” The question is, “Am I fulminant and infectious right now and a risk to other people right now—even if I have no symptoms.” So this is no longer a medical question. This is one of public health and the form that rapid testing takes, the primary beneficiary is not actually the person taking the test. The primary beneficiary of a rapid test are the people around the person taking the test, because knowledge, of knowing that you're infectious, allows you to not spread to the people around you. And that I think, is one of the most important pieces here and that's who benefits most. If you're asymptomatic, and you know that you're positive, you're going to have to isolate for 10 days. As a as an individual, that's not benefiting you, you're not going to work, you're not seeing your family, you're isolating for 10 days, but it's benefiting the population around you. And that makes it a great public health tool. Because it's specific. It's very, very, very specific to only turn positive when you're a risk to other people. It's not overly sensitive, like PCR—which PCR stays positive for a long time after you've been infectious. So it's actually a poor public health tool, because we don't want to be erroneously isolating people or asking them to isolate just because they were infectious four weeks ago and are still remaining PCR positive. So PCR is almost too sensitive for public health. And the time frame for it is not commensurate with the need. A rapid test gives you an immediate result. And so if I'm currently spreading the virus right now, and I'm about to go walk outside and go to a family's house or whatever it might be, getting a result back in two or three days doesn't do me any good to infect others. I need a result right now. And that's where rapid tests are just so crucial. They can also be accessible. Because they're rapid, because there's simple little pieces of paper, I can have them in the cupboard, in my kitchen, or in my bathroom or wherever. And just like somebody might go and pull out a band aid, if they don't need to, I could go say okay, I want to go to visit some family members who are elderly, I'm just going to pull out a rapid test for my cupboard and just use it. Maybe I have no reason to think I'm positive. But I do know that I took the bus this morning, whatever it might be. And so I can just have these tests available. And it makes them very, very powerful public-health tools to answer in real time, “Am I infectious right now?”

Jonathan Shaw: So in that sense, you're saying that, for public health purposes, rapid tests are more accurate than PCR tests?

Michael Mina: They are absolutely more accurate, which is why it's so hard to have been on this kind of campaign to educate the population for so long about the use and utilization of these rapid tests. And then every media piece that I see whether it's in New York Times, Washington Post,STAT, it always starts with somebody saying, “Rapid tests are less accurate than PCR, but.” And I actually think that that continues to do damage. They are actually more accurate for the question, “Am I infectious now?” Because PCR is actually very poorly specific for that question. You have no idea if you’re PCR positive if you're currently spreading, or if you're spreading three or four weeks ago. With a rapid test, if you are positive, you should very much consider yourself infectious, because it's highly, highly specific for the infectious stage. And if you're negative, even if you still have some remnant virus in you, if you're no longer a danger to others, then you'll be negative. So it's a very, very good and accurate public health test.

Jonathan Shaw: Why do rapid tests still cost so much?

Michael Mina: Well, I think that is a phenomenon that's occurring in the United States alone. And it is largely because we have not had many tests available to Americans. Demand has far outstripped supply. And largely, it's because we haven't had enough of these tests get through the regulatory barriers of the FDA. And so we've had very, very little market competition. In much of the world, we've seen governments and market forces drive costs way down to the point where a consumer can go out to their local grocery store and buy, you know, a number of tests for you know, $2. They could get two different tests. And in the UK, you get them for free. Anyone in the UK can actually go in and order online every single day, you can order a box of seven free rapid tests. In the United States, we don't have the scale of testing. We don't have the manufacturing capacity, with the handful of companies that have been authorized, to create those market forces. It's starting, we're starting to see capacity build, and we're starting to get some more of the companies that are selling for less expensive overseas now driving the prices in the United States down. This could have happened last year, unfortunately, in 2020. It didn't. And, you know, I don't really see it happening before 2022, unfortunately. But I do think we will get to a point where the costs will come down. But it's only happening as a result of this sort of long slog of getting through the FDA barriers, which have been unfortunately, focused on the wrong use of these tests. The FDA evaluates these test as medical devices. And as we just spoke about, when you try to compare a rapid test to a to a medical device, you're actually measuring different things. And so it's caused a lot of the companies who make really terrific rapid tests—it has barred entry for them into the United States, because the barriers to entry are so great imposed by the FDA, that they've just said, “Well, never mind, I'm just going to go sell our tests in Europe,” for example.

Jonathan Shaw: Has there been any economic research into whether making them free is cost effective? From a public health perspective?

Michael Mina: Yeah, actually, I led a number of studies along with Professor Jim Stock in the economics department here at Harvard. And I want to give him the most credit, actually, he really led the effort. I was just sort of coming in from the more public health side, and he was coming in from the economic side. And to Alan Garber's credit, Alan Garber is the provost of our university, he was actually the one who called me up and called Jim stock up and said, “Hey, you know, there's a lot going on with this pandemic. But I don't think the epidemiologists are talking to the economists. Could you two collaborate?” And that was way back in early 2020. And so we did, and that relationship led to a number of papers now published that show the massive return on investment, that would have happened—not even to mention the prevention of lives lost—but just the financial return on investment, had the government really scaled up and fully paid for these tests in the summer and fall of 2020. The return would have been in the hundreds of billions of dollars, if not a trillion dollars. As we are now in the vaccine era, we've kind of updated that model to say is there still a benefit to make these tests widely available and perhaps free, and it's still a great return on investment. It's in the tens of billions, not hundreds of billions at this point. But suffice it to say that all of the economic modeling suggests that by boosting the economy to fully get reengaged by stopping school quarantines and closures, which ultimately cause parents to leave the workforce for, you know, a week or so, the return is really very, very great.

Jonathan Shaw: The risk of dying from COVID-19 doubles every five to six years or so until, among the elderly, the rapidly growing risk of becoming ill overwhelms the reductions in risk that are conferred by vaccines. That means that a vaccinated 80 year old has about the same mortality risk as an unvaccinated 50 year old and a vaccinated 45 year old has a higher risk than an unvaccinated 30 year old. Is this an argument for supplementing vaccination with rapid testing, particularly in and around the elderly?

Michael Mina: One-hundred percent. I believe very firmly that a vaccine only approach is not the right approach having vaccine as your number one, two and three objectives—absolutely. But we need to be supplementing our efforts. Because as you say, vaccination isn't perfect. And I think we have to recognize exactly what you just mentioned, which is that the elderly are still at an increased risk of dying, even if they've been vaccinated. And more so than an unvaccinated younger individual. And when we start balancing these pieces out, we really need to say, okay, if we're willing to take resources and put it into vaccinating these younger people, then we should be also willing to create other resources to keep the elderly sufficiently safe. And that's where rapid tests do come in. I think there is no reason today why any nurse or caretaker should be allowed to walk into a nursing home, or a visitor for that matter, and not have to use a rapid test out the door. There's just no reason that we didn't put this in place a year ago. We should be doing this in businesses as well. There's really no good excuse, but in particular, for senior-living facilities, for nursing homes, for hospitals. There's no excuse at this point, given how abundant these tests could be that we're not just saying, “Hey, before you walk in for your shift, and you're a nurse working with cancer patients, or with elderly, take a rapid test.” And that that should have really been done a long time ago. And I think that the more we can give knowledge to people about their infectivity status, the safer those around them will be. So these rapid tests are. I like to think of them not as this this onerous device, this medical thing. It's knowledge, it's empowerment to ensure that you are being safe around the people around you. And that's what these are so powerful for. And I think we should absolutely be trying to use them to use all the tools to our advantage. We don't say vaccines are here, so, you know, nurses don't have to wear masks. We know that there's still obviously there's some, you know, arguments against masks at this point in this country. But we do need all the layers. And I think that rapid tests are perhaps the most profoundly powerful layer to prevent transmission, even more so than vaccination.

Jonathan Shaw: Beyond their use in schools and nursing homes, you've studied the use of rapid tests in companies. What did you learn?

Michael Mina: Well, one of the most important things we found was that it made people sit easier when they were at work, knowing that the people around them all tested negative that morning. It was a great relief for the employees. It also was a method that actually allowed people to find out that they were infectious before going to work. Which, ideally, you know, it was very important for stopping outbreaks from growing, we've used this in the workplace, we also just used such a model at a conference recently where every participant—it was a multi-day conference—and every participant had to use rapid tests before showing up for the meeting that day. And they used a service, which was doing proctored testing. So your results, and the fact that you actually did the test was authenticated. And were also nicely reported to public health, and in this case, reported to the conference. So if you're positive, you just weren't allowed into the conference. And that actually served to stop what could have been a number of outbreaks. There were a number of people who were found to be positive, and they didn't go into the sessions that day, or, you know, ideally for the for the rest of the week. And so I think what we have found through the use of these different tests, and these different settings at work, and conferences, things like that—is that people are very willing to use it once they get the hang of it. It turns out these tests are very simple to use once you've done it once. And it really does create a sense of ease, where people feel a little bit less anxious about being around their colleagues than they otherwise would have.

Jonathan Shaw: On September 28 2021, The New York Times ran a story that showed how partisan politics have affected vaccination and death rates in the United States. Vaccination rates among politically right leaning Americans are significantly lower than in the rest of the population. Death rates from COVID-19 were more than three times higher in counties with a large share of Trump voters than in counties with a large share of Biden voters. Do rapid tests have a chance to be more equally embraced by all Americans? Or is it your sense that these patterns extend to the willingness to use rapid tests as well?

Michael Mina: I think that they are very able to be embraced by both sides. In fact, I've spoken to Congress on many occasions to the New Democrats to the Heritage Foundation, and to the to the most right-leaning people in Congress. And throughout all of last year, most of this year, I would say that these tests have been seen as a very bipartisan issue. And the reason is, is because there's so many ways to use them. But ultimately, all of the ways can be on the people's terms. So for example, there are a lot of people who don't want to use a test or get a vaccine because they don't want to be told what to do by Big Brother, or they don't want Big Brother looking in. Well, the nice thing about a rapid test is you could use it at home without ever having it be reported. You know, and there's downfalls to that from a public health perspective. But I would say if those people aren't going to get tested either way, I'd much rather that they know that they're positive and take local action, to not spread it to their community members, versus them not knowing. And so these rapid tests can bring the public into the public health efforts. And I've said in the past that this is a public health emergency, this is a public health problem, this pandemic. And the only way, truly the only way that we will solve it is if we have full buy in from the public. And that means sometimes that we have to—we're not going to get perfection in everything we do. And sometimes as public health officials or practitioners, we have to give a little bit to get more back. And in this case, maybe we give up some public-health reporting, and we give people the tools just to know on their terms if they're positive. What I'm concerned about now is that unfortunately, one of the few bipartisan tools that we had, which is rapid tests, is now becoming politicized. And that is not intentional, I don't believe. But it became a central theme in presidents COVID-19 Action Plan. which is essentially vaccinate or test for companies that have over 100 employees. This, I think, I do worry is going to politicize testing as well. And it sort of pits testing against vaccination. And it's sort of one or the other. And I think that that is the wrong way to look at it. It's you vaccinate, and you test depending on the situation. And these are not substitutes for each other. But unfortunately, I think a potential ramification of the COVID-19 Action Plan is becoming the politicization—did I say that correctly?—is making these rapid tests much more politically sort of heated and getting them out of that nice bipartisan arena they have been living in.

Jonathan Shaw: Some observers have suggested that the partisan divide revealed by the pandemic may be overstated. Because among people over age 65, are eligible for Medicare, 95% have received at least one dose of vaccine. Kaiser Family Foundation Data Point to the lack of health insurance as the best predictor of who is not vaccinated rather than politics, income, race, age, or where they live. If this is true, then rapid tests will have to be free. But will that be enough? How can problems of distribution in education be addressed, particularly in rural areas where many of those people without health care live?

Michael Mina: So this is something I've been talking about, really, since the beginning of all of this. And it always kind of gets buried people have been so interested in the sensitivity and specificity of the test. But I've often said that we, in this pandemic, have continued to neglect what is perhaps the most important tool that we could have had since early 2020 to fight this pandemic, which is, frankly, the media. And to own—not own the media—but the advertising, if you will, of public health efforts. There's no reason why we didn't get Coca Cola’s best ad agency and best marketing agencies involved with pandemic efforts to educate the public, whether it's about vaccines or about testing. These companies are expert in knowing how to convey information to people in a very localized way. So if you're right leaning or left leaning, they somehow get everyone to want to drink Coke. And I mean, that's an obviously kind of silly example. But it's what these companies are good at doing. And I think that education can't just be some CDC website and documents. It can't be left to some random commercials put out by the CDC or by the Department of Health. It needs to be a full-fledged effort to educate the public about the vaccines, about tests about all of these different issues. And I think we still have an opportunity to really have large-scale media outreach. Unfortunately, when we don't do that, when public health doesn't utilize these agencies and these marketing agencies and kind of trie to get people the right information, what ends up happening is we have the media does its thing. And the media is, as we all know, very leans very heavily towards negative information. You know, whenever something goes wrong, that gets put on the front page. But when things go, right, it's never discussed—especially in public health, because when things are going right with public health, it's boring. Nobody cares to read that an outbreak didn't happen today. They want to know when an outbreak did happen. And so that leads to this major bias that the that the tools we have fail. But that's not true. It's just that the reporting—there's a major reporting bias. And so I think, to get back to your question, we can do this. We can educate people, and to get rapid tests to people, we have to couple it with education, and that education can't just be some Department of Public Health saying, use a rapid test twice a week. That is not good enough. We need to get people to understand why it's important to them emotionally, to let them know that these are good tools that will keep their family safe. This isn't some political effort. This is really for the people. And we can make these tests free. We can give it to people on their terms, say, look, use it or don't use it, but have them in your house. And we'll try to give you as much information as we can about why this can best support you and your family as a public-health effort. And I think we can do that, it's not too late. But certainly every month that goes by, it feels like these tests are becoming more and more politically charged. And I do worry that we're going to get to a critical state where people just overtly and outright sort of reject any control measure in anything you know, having to do with COVID

Jonathan Shaw: Dr. Mina do you have any closing thoughts?

Michael Mina: I think the major takeaways that I want people to understand are that these tools exist. I and others are working very hard to make them more affordable and accessible to Americans. And I think that they are going to be, and continue to be, very important tools as we shift into a new phase of this pandemic. And that phase in this case is going to be an endemic of this coronavirus. Many young people are not going to be landing in the hospital with this virus, especially who have been vaccinated. But we have to, unfortunately, understand that many older individuals are going to continue being vulnerable. And yes, we will boost them over and over and over again. But there will continue to be vulnerabilities. And we have to continue to keep our eye on what are all the tools at our disposal that have the least effort associated with them that have the greatest good. And I think things like a 30-second rapid test in the morning can do a tremendous amount to keep the vulnerable in our communities safe as we learn to live with this virus, you know, over the coming years before we really build up a sufficient amount of immunological protection across the whole population to so that even the elderly begin to really benefit the most from it.

Jonathan Shaw: Thank you, Dr. Mina.

Michael Mina: Well, absolutely. This has been a pleasure to be on.


This episode of Ask a Harvard Professor was hosted by Jonathan Shaw and the season is produced by Jacob Sweet and Niko Yaitanes. Our theme music was created by Louis Weeks. This fourth season is sponsored by the Harvard University Employees Credit Union and supported by voluntary donations from listeners like you. To support the podcast, visit harvardmagazine.com/supportpodcastIf you enjoyed this episode, please consider rating and reviewing us on Apple Podcasts. Contact us with questions at [email protected]




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