As coronavirus cases continue to increase across the United States, the term “second wave” and the question of whether we’re in its midst or about to face one are dominating headlines. In states such as Arizona, Texas, Oklahoma and Florida, coronavirus cases continue to tick upward. Despite that, plans for reopening continue. What exactly does a “second wave” entail when it comes to a pandemic?

Below is a transcript of a conversation that Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, had Thursday with The Washington Post. It has been edited for length and clarity.

How can we predict the end of one wave and the beginning of another? Can we mark this?

Anthony S. Fauci: You know, you actually cannot predict [a wave]. You can get a good feel by depending on how you respond to the ongoing infection dynamics in the community. You know, the way I explain it is that what you have is you have two forces. You have a virus, [that] if left to its own devices will continue to rapidly go through the population. And then you have your attempt to do something to blunt that progression of virus through society.

The one that we’ve been dealing with over the last few months has been what’s called “mitigation,” namely to, in a very dramatic way, separate the virus from people by the so-called “physical separation” of one person who might be infected from another. That’s the reason why we talk about the distances of physical separation, wearing of a mask, washing hands to interrupt that interaction between the virus and society that has been successful to help contain the onslaught which we’ve unfortunately experienced, which has been very severe, with now 120,000 deaths . . . in 2 million cases in the United States, which is extraordinary. That you would consider a wave.

How do you go from one wave and not have another wave going? Well, first of all, unfortunately for us, we still are in the first wave because even though there’s variability throughout the country, where some places like New York City are going very nicely down, staying down so that they can start to reopen, simultaneously, we’re seeing in certain states an increase in cases and even now an increase in some of the states of hospitalization. What that directly is related to is complicated. It’s a combination of testing more, but not explained completely by testing more, because some of the states really do have a real increase in the percent of the tests that are positive.

Right now, when you talk about waves, you would have to say everything goes way down like as occurred in some countries. And then do you keep it down enough to prevent a second wave? For example, in a different season, as we get into September, October, November, when you have the complicating issues of having an influenza outbreak that invariably occurs every season. Bottom line, you can’t predict. It’s going to depend on your capability and your effectiveness when you do get these little blips of infection, which we will invariably get, that you have the systems, the testing, the manpower to do the identification, isolation and contact tracing. If you do, it is not inevitable that you’re going to have a second wave in the fall. Nor is it inevitable that, even now, as we enter the summer and we start to pull back to normalize, you will start to see cases if properly addressed.

You don’t necessarily have to have a resurgence in a wave that has not even gone down. So that’s the reason why I say when people talk about a second wave in the summer, you can’t talk about a second wave in the summer because we’re still in the first wave. We want to get that first wave down. Then we’ll see if we can keep it there.

Is there a specific number of cases or tests or something that we would have to reach for you to say definitively the first wave has ended?

Fauci: What you’d like to see is when you test, broadly in surveillance, that the percentage of people who are positive in your society and again in the United States — I have to emphasize this, and I cannot emphasize it too much — that you have to be careful when you make statements about when would you be satisfied of doing A, B and C in the United States. The United States is a very large country. It’s very heterogeneous, and you can’t look at it in a unidimensional fashion because what you’re able to safely do in one part of the country, in one state, in one city, may be completely different in another because of different dynamics.

But what I would like to see in any given region, state, city is that the percentage of your testing that turns out to be positive for infection continues to diminish and diminish and diminish until you get it in the low single digits. When you get there, then you could feel you have a degree of good control so that when you do get a new infection, you can prevent that infection from becoming a resurgence of essentially many, many more. Because I think the idea that you’re going to eradicate the virus is just not going to happen, certainly not within the immediate future, because of the extraordinary transmissibility, capability that it has. It’s one of the most highly transmissible viruses that we know of.

In March, Dr. Deborah Birx, the White House coronavirus response coordinator, predicted there could be 200,000 coronavirus deaths in the United States if we “do things almost perfectly.” You later testified in May that Americans would experience “suffering and death that could be avoided.” Do you have models or predictions for the number of deaths in the United States this summer?

Fauci: I am skeptical about models, even though they are helpful in some respects, because as I’ve said often and it’s worth repeating, models [are] only as good as the assumptions that you put into the model, and the assumptions change based on real data. So you would say that if you do this at this rate, you can model mathematically and computationally that you’re going to have X number of cases. I’ve always said that you can change the model by how, in real life, you address the virus.

So if you were to say, well, if you effectively do this, you’re going to get this many cases. I say, okay, that’s what the model tells you. But let’s prove the model wrong. Let’s do so well in our containment that instead of the projection of a certain number of cases, you can do much less. And that’s the reason why I say we don’t need to assume because the model tells us something that we can’t do better. You can’t get complacent and say, ‘Oh, the model says even though we’re doing substantial mitigation, we’re still going to get X number of cases,’ because that might get you to feel, well, that you’re helpless. You’re not. There’s a lot you can do. And a lot of that is spelled out in the guidelines of how you can, with a good degree of caution and in a way that’s very measured and prudent, go to the various checkpoints, and then you don’t go to the next checkpoint until you’ve accomplished what you needed to do the previous checkpoint.

And if you look at throughout the country, there are some states and some cities that have been quite successful in doing that. I mean, you could take New York City, for example, New York metropolitan area, [and] the state itself where they’ve gone from the worst possible suffering that you could imagine, because they got hit very hard, to containing it with mitigation, to then getting to the gateway part, which allows them to go into Phase 1. And now they’re trying to go into Phase 2. The same with the Washington, D.C., area, which has gone from gateway to Phase 1, and the city is trying to make that determination if they go down low enough, they go to Phase 2. If you do that in a measured way without needing to jump over one of those checkpoints, then it’s likely that you’ll be quite successful in, over time, getting that number down where . . . you start feeling comfortable about doing some of the things that you can’t do now because of the restrictions.

Dr. Birx had said that quote, “do things almost perfectly.” Do you think that we’ve done things “almost perfectly”? Do you think that that 200,000 number that she put out there is realistic?

Fauci: So . . . you may see a situation where the leadership, be that a governor or a mayor or someone at the leadership role at the community level, sets forth and says we should do the following guidelines: We should be maintaining distance, we should be wearing a mask, and we should avoid crowds. And if you’re at a certain phase, well, maybe we could take take out or maybe we could advance to sitting outside in a restaurant or maybe we can advance to going in and sitting spaced apart, all the different phases that . . . the guideline says. But as we are imperfect human beings, what happens is that you will get people, even in the context of the guidelines being promoted by the leadership, [who] will say, “No, no, to me it’s an all-or-none phenomenon. I’m either going to be locked down, or if you unlock me, I’m going to go out. I’m going to go to a bar. I’m going to congregate. I’m going to go to crowds.”

That’s risky. And that’s what we’re referring to, that if you do it perfectly, but unfortunately, we’re not perfect. And we have some people — understandably, because of this urge to get out and get back to normal — start leapfrogging over some of the restrictions which do nothing but have the potential and the risk to set us back. And that’s the thing that I’m concerned about, and that’s the reason why we need to continue to stress that we can end this. This will not last forever. But the only way it is [ending] is if we address it in a way that’s cautious and in a way that’s prudent and continue to go in the right direction.

Good public health measures could be a tool to actually get us to where we want to go with normalization, getting jobs back. So it’s not all or none. Approach it in a way that’s prudent, and we will get to where we need to go. We will be able to end this.

We’re already seeing spikes and the repercussions of those spikes as states begin to reopen. What types of mitigation are still important to remember? Are there measures you feel are being ignored or quickly forgotten?

Fauci: You’ve got to be careful about general statements because they don’t apply to every state or to every city. Certainly, it’s a mixed bag. The best way to avoid infection when you are in a location where the dynamics of the virus are clearly active [is] avoid congregation and crowds; wear a mask at all times when you have the likelihood that you’re going to be running into somebody. Obviously, if you’re in your room alone, you don’t need a mask. If you’re out in the woods, you have a mask around your neck and you just don’t wear it. You see someone coming 50 feet away. You put the mask on.

You stay away from situations in which you’re inviting an outbreak. . . . You see people — understandably, because people are penned up, they want to get back to normal — do something that really is indiscreet, namely getting in, crowding in a place, particularly in a bar, being [in] a situation where you have a crowd of people where . . . you should not be doing that, that you should be maintaining a certain distance, be that 10 feet, be that 20 feet, be that 10 people, be that 50 people. You’ve got to look at the guidelines that are appropriate for the place where you happen to be. It’s a big city. It’s a town. It’s a county. It varies throughout the country. . . . What might be good in one area of the country is not quite ready in another area of the country.

In addition to coronavirus, we also have nationwide protests and an election five months away. Do you have concerns about resuming political rallies and big protests?

Fauci: I can answer your question directly by saying when you have a congregation of people, you increase the risk. It doesn’t matter why they’re congregating or where they’re congregating. When you have a congregation of people in a setting in which there’s active virus circulating in the community, you are at risk. You need to wear a mask.

The best possible thing is to avoid crowds no matter what the venue is. If for one reason or other, you’ve made up your mind that no matter what I say or [what] any other public health officials say, you’re going to congregate anyway, then wear a mask. And please resist the temptation when you’re at whatever it is, you’re at a demonstration or rally or whatever you do, that when you get animated and want to express yourself, don’t take your mask off. Those are the things you need to do.

Is there anything that you would stress to President Trump if you could speak to him? Does he still receive regular briefings from doctors about the coronavirus?

Fauci: We and the task force work very closely with the vice president, who’s really quite good at listening and analyzing and discussing and giving you the opportunity to give the facts, express the facts and express your opinion. There’s no doubt about that. And then what happens is that then it goes up to the next level. And I’m absolutely certain the president hears these things, and he takes what we say as well as [what] others say, who have other interests and other agendas, and then he makes his final decisions. So I’m confident that it’s not necessary for me to speak directly because he knows what goes on in the task force meeting, because I’m absolutely certain that the vice president regularly briefed him on that.

In past pandemics, we’ve seen examples where subsequent waves end up being deadlier than the first. Do you believe that will be the case with the coronavirus?

Fauci: No, I think that it would be somewhat, I would say, a stretch without any data to make a prediction. . . . We don’t necessarily have to accept the inevitability that if we get the cases way down this summer, that we will have a “second wave” in the fall and the winter. Historically, with the infamous 1918 pandemic where so many tens [of] millions of people died, 50 to 100 million people throughout the world had this second wave. It started off in the spring of 1918 and then when it came back into the fall and winter, what you had was a second wave. It is not inevitable that we will have it. We can do something to prevent it. And I think . . . it just doesn’t have any evidence to indicate that it’s going to be any better or any worse than what we went through the first time. I think we got hit pretty badly the first time. And you’re talking about right now . . .120,000 deaths in the United States and over 2 million infections. That’s a pretty robust wave. I’d like to see that come down to practically nothing before we start discussing a second wave. We are still in the first wave. Let’s focus on getting ourselves out of this one.

If you had a sentence or two of advice — nationwide, worldwide — for people to just keep at their forefront of their mind as life starts to resume to whatever their new normal is, what would that be?

Fauci: One is that this will end, and it will be within our power to end it both from a public health standpoint and hopefully within a reasonable time with the scientific advances that bring us interventions in the form of vaccines and therapy. But we are all in this together. And . . . it’s important for the economy and for employment and for people’s livelihoods to get us back to normal.

The way we’ll get back to normal is by pulling together to try and end this. And . . . you have a responsibility for your own health. But also, since we live in a big country and in a global community, what we do as individuals will have an impact on the success or not of getting this outbreak under control. So,. . . please hang in there. [We know] it’s tough. It’s tough for everyone. But remember, we are in this all together. We’re not just separate individual components. We’re in it together.

Adriana Usero contributed to this report.