I recently spoke by phone with Dr. Ashish Jha, a physician and the director of the Harvard Global Health Institute, who has been tracking the coronavirus story closely over the past couple months. He has been especially outspoken about the Trump Administration’s slow response to the threat and also the scandalously slow pace of testing in the United States. I asked Jha to explain where the government went wrong, and whether our existing health-care system has exacerbated the crisis. In our conversation, which has been edited for length and clarity, we also discussed his biggest concerns about overwhelmed medical facilities, how more testing could have spared us from worst-case scenarios, and why closing borders to prevent epidemics often draws attention away from measures that would do more good.

You have changed your Twitter name to “Ashish ‘We need PPEs [personal protective equipment] to protect docs & nurses’ Jha.” What are you calling for?

So, look, the challenge in front of us in the upcoming week or two—and, actually, lasting much longer than that, but that’s when it is really going to hit—is that the number of patients arriving with COVID-19 infections is going to spike across American hospitals.

There are lots of people thinking about hospital beds and I.C.U. beds and ventilators, and those are absolutely critical things that we need to be thinking about. But one of the things I am really worried about is personal protective equipment for nurses and physicians. Hospitals are already running out of masks and gloves and gowns, and what that means is that doctors and nurses are going to be faced with a dilemma, which is do they take care of sick people with coronavirus without adequate protection, knowing that they are putting themselves at risk, or do they let these people die? And I know what doctors and nurses are going to do. They are going to take care of these people. And then the health-care workers will get sick, and we are heading toward a major crisis, because if we lose doctors and nurses it will be really hard to take care of sick people. So that’s what I have got very worried about in the last couple of days, and recently I have just been changing my Twitter handle based on what I think we need to focus on next, and this to me is a really critical issue that I think is not getting enough attention.

What is the reason for the P.P.E. shortage? Is it a built-in problem with the health-care system, or were we just not prepared enough for something like this?

We weren’t prepared for this specific surge of patients. This shortage is also happening in Italy, so we don’t think that this is a uniquely American problem. But there are two things that are contributing to this. One is that, because people knew this was going to be a problem, people started to hoard. So patients and some people who work in hospitals are grabbing extra masks and extra gloves and taking them home, which of course is silly, because most people will not need them in their homes. That is not what is going to protect them. That has created a run on these supplies, so that is one part of the problem.

The second part of the problem is that our supply chain just wasn’t designed for a massive surge in the need of these things, and nobody in the White House until really recently has made this a priority, and no one in the federal government has tried to figure out how to increase the supply of these products, and that is why we are finding ourselves in a shortage.

You have taught and written about the American health-care system. What does it prepare us for and what does it leave us vulnerable to? And how has your analysis changed after what you have witnessed in the past month?

I have written and thought a lot about the American health-care system. One of the things that is really amazing about it is how dynamic and responsive it can be. So, for instance, one of the things I have seen is that, when we have had this massive failure at the federal level with testing, all of a sudden you have facilities, universities, and hospitals building their own tests. Now, of course, that is not the ideal way to do this. The ideal way to do it is to have a strong, coördinated federal response, but one thing that has given me more hope is that because the health system is so fragmented—and fragmentation is usually a bad thing that causes all sorts of challenge—in this case, when there has been a failure at the top, the system has actually responded by gearing up on its own. So now we are doing twenty-five thousand to thirty thousand tests a day. My hope is that that number will gear up. It is not because there has all of a sudden been great leadership in Washington allowing that to happen. It is literally because cities and states, working with local hospitals and universities, are ramping up. It’s a remarkable thing, and I am not sure it would be so easy to do in almost any other country. So that’s the upside.

Of course, the downside is that because the system is so fragmented, and because every payer is different, there are all these very arcane rules. How are we going to pay for all this stuff? Are people going to have to pay out of pocket for a COVID test? That kind of stuff doesn’t come up in other countries. Because, even though some other countries have very decentralized systems, they are much more effectively coördinated at the federal level than we are. So that stuff tends to work better in other places. We are learning both the upsides and downsides of our system. It does have some advantages, but, man, it creates a lot of new challenges, as well.

You recently told Bloomberg News, “We’re so far behind this thing at this point. And the reason we’re so far behind is because we’ve had so little testing. This is such a rapidly moving infection that losing a few days is bad, and losing a couple of weeks is terrible. Losing 2 months is close to disastrous, and that’s what we did.” Can you explain the scenario where we have more testing starting two months ago, and what you think that would look like today?

Oh, my God, if we had got on top of this thing two months ago, America would look very, very different. So, let’s walk through that scenario. Imagine that when the W.H.O. put out its test kit [in January] we either took it or built an effective test ourselves. We would have then ramped up those tests. The data by late January was very clear that we were going to see a lot of these infections in the United States, and, actually, we had started seeing the first cases from travellers from China. We would have started testing people who had symptoms. Initially, it was the travellers, because that is how it got introduced. We would have isolated those people. We would have had contact tracing, which is really critical. Everyone that had been in touch with them would have been monitored, and any of them that showed symptoms would have been tested.