The newest designs are smart, streamlined, and inexpensive. Will they be enough?
On Monday, March 9th, Jake Kittell, a research engineer and machinist who builds scientific equipment for the University of Vermont, in Burlington, came into work fired up. Approaching another engineer, Carl Silver, he said, “We gotta build a ventilator.”
“That sounds great,” Silver replied. “What do we know about ventilators?”
Neither had ever seen one. But the coronavirus pandemic, once an abstraction, had recently made itself felt in Seattle, New York, and other American cities, and doctors had warned that a shortage of ventilators could hasten the deaths of thousands. “You feel like you want to do something,” Silver recalled. The next week, Kittell e-mailed another professor at the university, Jason Bates, with whom they had worked in the past, and whom they knew to be a lung expert. We have a shop, he wrote. Can we build a ventilator?
Well, sure, Bates thought. He’d been working on the same problem for the previous four days.
Bates has wispy white hair and speaks with lucid, cheery confidence. Originally from England, he is a professor of medicine and of biomedical engineering, and teaches in both the university’s engineering department and its medical school. The author of “Lung Mechanics: An Inverse Modeling Approach,” he is one of the world’s foremost experts on ventilator-induced lung injury, or vili. Earlier in his career, at McGill University, in Montreal, Bates and his team invented a computer-controlled ventilator for mice that is still used by researchers. By tuning the machine’s settings and seeing how a mouse’s lungs react under pressure, scientists can study the physiology of lung disease. They can also explore how different styles of ventilation—in which air is moved into and out of the lungs at various volumes, pressures, and rhythms—can help or hurt a damaged lung.
The previous Friday, March 13th, Bates had heard from Matt Kinsey, a pulmonologist at the University of Vermont medical school. A covid-19 patient there had been placed on a ventilator, and the physician in charge had decided to use a technique known as airway pressure release ventilation, or A.P.R.V., in which the device delivers near-constant air pressure, with an occasional quick release. (Try taking a long, slow breath in, then puffing out, quickly but gently; repeat.) Kinsey passed on a text message from the physician: “APRV is da bomb for covid.” Bates said, “I was intrigued by this because I’d been studying A.P.R.V. and trying to figure out how to optimally deliver it.” He suspected that covid-19 inflicted more damage when the lungs were swinging between full inflation and full deflation, and had come to believe that A.P.R.V., by avoiding those extremes, was probably the gentlest ventilation strategy for those suffering from the disease. Now his theory was being put to the test.
The ventilators used in today’s I.C.U.s are expensive, in large part because they are configurable. Newer models have touch screens that allow clinicians to change and track dozens of parameters, carefully adjusting how breaths are delivered. Bates began wondering whether it might be possible to build a pared-down ventilator that did nothing but provide A.P.R.V., to be used when the supply of fancier ventilators ran out. A typical I.C.U. ventilator costs between twenty-five thousand and fifty thousand dollars. Bates replied to Kittell’s e-mail with a document titled “APRV for $10 (okay, maybe $50 . . . ).”
In an included schematic, Bates had sketched a simple device: a box with three holes in it. Gas under pressure—which many hospitals have available from wall outlets—would flow into one hole and out another, to the patient. In normal breathing, exhalation typically takes about two to three times as long as inhalation; in A.P.R.V., the length of exhalation is reduced from several seconds to about half a second, while inhalation can take five seconds or more. To create this modified rhythm, the box’s third hole would be blocked by a rotating disk that also had a hole in it, and that was spun by a motor. When the holes briefly aligned, the machine would exhale through the opening.
By the next day, Silver had built a prototype and sent Bates a video. A rubber glove was attached to the side of a box with some zip ties. The glove inflated, then deflated, then inflated again. “I saw that and everything changed,” Bates said. Soon, the university agreed to fund the device. Kittell and Silver were given free rein in the shop; a lung analogue was brought in from the hospital for testing; a regulatory expert began preparing an emergency report for the Food and Drug Administration, which had created a special approval process for stopgap ventilators; and several local contract manufacturers were lined up so that the device, now known as the Vermontilator, could be mass-produced.
Engineering is quiet, methodical work, not often the stuff of high drama. But for many engineers the coronavirus has been a call to arms. Not since the space race has the whole world been so invested in problems that are fundamentally technical. During the Apollo 13 mission, a buildup of carbon dioxide was slowly poisoning the crew; the nation watched as the astronauts, working with engineers in Mission Control, jury-rigged a filter using duct tape and spare parts. In the film “Apollo 13,” from 1995, an engineer with a pocket protector explains the situation to his colleagues: “The people upstairs handed us this one, and we gotta come through.”
Since February, engineers in industry and academia have been working on designs for cheap, easy-to-build ventilators. Ford has christened its effort Project Apollo. And yet comparisons to the moon landings may understate the complexity of the problem. covid-19 is a mysterious illness, and ventilators admit to many styles of operation. In the best case, the machines keep patients with failing lungs alive, buying time for the body to heal. In the worst case, they can aggravate lung damage. In the course of the pandemic, critical-care specialists have disagreed about how the devices should be operated and at what point in a patient’s decline they should be used; mortality rates for covid-19 patients on ventilators have ranged widely. Manufacturing a ventilator is difficult, especially during a pandemic, when supply lines are unreliable. Different designs negotiate different bargains between cost and functionality. Reaching the moon is challenging enough. It’s harder when no one is sure where the moon is.
The lung is a passive participant in breathing. It’s the diaphragm, a large muscle that cuts the human body horizontally in half, that does the work. When you inhale, your diaphragm pulls down like a piston, creating negative pressure around the lungs, while the muscles of the chest wall pull up and out. Air, drawn in through the nose and the mouth, flows through the trachea and into the bronchial tree, which fans out into the lungs. There, the breath nestles into hundreds of millions of gossamer sacs called alveoli. Blood, meanwhile, has arrived at the rendezvous through a network of capillaries, the smallest vessels in the circulatory system. Under a microscope, the alveoli look like bunches of grapes, and the capillaries like the mesh sacks that hold them. The tissues are so exquisitely thin that oxygen and carbon dioxide can diffuse across them, between air and blood. The contact surface between the two networks, if it were unfolded flat, would be more than half the size of a tennis court.
The alveolar flesh is elastic, and delicate like fruit pulp. It fares poorly when infected. The coronavirus multiplies in the alveolar cells, tearing them apart as it escapes; in the resulting chaos, fluid can leak into the air sacs, capillaries can constrict or clot, and tissues can become inflamed and stiffen. As the infection spreads, the number of healthy air sacs declines, and the exchange of gases becomes less efficient. A patient whose lung function degrades in this way can develop acute respiratory distress syndrome, or ards.
When a covid-19 patient arrives at the hospital with shortness of breath, physicians use a pulse oximeter, clipped to a finger, to monitor her blood-oxygen level, while supplemental oxygen is delivered. If the oxygen level continues to decline, doctors bring in a ventilator. A device that looks like an oversized shoehorn is wedged over the patient’s tongue and used to peel back the epiglottis. Then a tube is fed down the trachea, where a small balloon is inflated to hold it in place. Patients are usually sedated and paralyzed before being intubated; people suffering from covid-19 may have to stay on ventilators for weeks, remaining sedated for the duration, and they are sometimes paralyzed again if their movement makes them hard to manage. It is an extreme intervention that, even when it saves a patient’s life, takes a toll on the body.
At the most basic level, a ventilator is a pump, no different from the plastic resuscitator bags that paramedics squeeze to push air into a patient’s lungs, in lieu of mouth-to-mouth. But, to avoid vili, the lungs must be ventilated with care. Too little air pressure and the alveoli won’t inflate; too much and they’ll distend and get damaged. The balance grows harder to maintain as ards progresses. The lung is like a lattice, with each air sac supporting its neighbors. Damaged alveoli can press up against one another, spreading weakness with each breath; strained alveoli can burst. During exhalation, the insides of the alveoli, which get stickier as they fill with fluid, touch and cling together; inflating them again requires peeling them apart. In lung-physiology circles, this is sometimes called the “Velcro effect.” “If you have that Velcro effect going on with every single breath, breath after breath, that’s incredibly damaging in a fairly short time,” Bates said. “You get in this vicious spiral that’s really hard to get back from.”
With a typical I.C.U. ventilator, a clinician has a few ways to modulate the flow of air. She can adjust the “tidal volume”—the total amount of air to be delivered with each breath. She can designate a target pressure, in which case the ventilator delivers whatever volume is required to generate it. (Imagine filling a bicycle tire: you pump until the tire is firm.) She can also select the degree of peep, or positive end-expiratory pressure—the amount of pressure that’s left in the lungs at the end of each exhalation. Higher peep prevents the air sacs from collapsing. By decreasing the duration of exhalation and maintaining higher inspiratory pressure, A.P.R.V., Bates’s preferred ventilation style, does everything possible to avoid the Velcro effect.
The Vermontilator will likely cost around one or two thousand dollars when it ships—more than ten (or fifty) dollars, but a fraction of the cost of a full-fledged I.C.U. ventilator. It’s so inexpensive because it’s a minimalist device made from around fifteen parts, designed specifically for A.P.R.V. If the Velcro effect is as central to covid-19 as Bates believes it to be, then this is a sound approach. But clinicians and researchers are still debating what kind of lung damage the coronavirus causes; they have come to recognize that it affects patients in unpredictable ways. “One of our mistakes at the beginning of this mass-casualty event was fixation: you come in with an idée fixe,” Sharon Einav, an I.C.U. specialist in Jerusalem who co-authored a set of well-known guidelines for critical-care surges, told me. “People knew ards. The intensive-care community has been discussing ards for the last twenty years. As time passes, we’re discovering that this disease has something more to it.” The Vermontilator is a bet on the nature of the virus that may not pay off.
If we could produce more of the high-end ventilators already in use in hospitals, doctors could choose their own settings. This is the cause now taken up by Ford and General Motors, which have each collaborated with a ventilator-maker—G.E. Healthcare, which licenses a design from Airon, and Ventec, respectively—to scale up manufacturing. In mid-March, Ford kicked off Project Apollo, after the company learned about Airon’s design; a personal introduction to representatives at Ventec led Mary T. Barra, the C.E.O. of G.M., to commit her company to Project V.
Ventec’s vocsn ventilator—the name stands for “ventilator, oxygen, cough, suction, and nebulizer”—was designed to perform the functions of five devices in one. “We are the first and only multifunction ventilator,” Chris Brooks, the company’s chief strategy officer, told me. (The vocsn was approved by the F.D.A. in 2017.) For G.M., Ventec has created a simplified version, without the cough, suction, and nebulizer functions, known as the V+Pro. Even so, Brooks sees it as a fighter jet in a race with prop planes. “There’s been a lot of conversation over the past few weeks with the shortage, a lot of very well-intentioned individuals and groups and very smart people, who have said, ‘Hey, we can create a ventilator,’ and ‘Hey, we’ve developed a ventilator overnight, it’s a hundred-dollar ventilator,’ ” he said. “There’s a reason that there are very high-end, very powerful and precise critical-care I.C.U. ventilators. That truly is what these patients need.”
On March 27th, in a tweet, President Trump urged G.M. to “START MAKING VENTILATORS, NOW!!!!!!”; in a subsequent tweet, he invoked the Defense Production Act to compel the company to do what it had started doing two weeks earlier. Preparing to manufacture ten thousand of Ventec’s ventilators per month, as G.M. plans to do, has required a crash effort. On March 19th, G.M. flew six engineers to Bothell, Washington, to study the vocsn production process. “We took a lot of pictures and a lot of video,” Gerald Johnson, G.M.’s head of global manufacturing, told me. The vocsn has around seven hundred parts; the V+Pro, around four hundred. By e-mailing lists of parts to around seventy of its “Tier 1” suppliers, G.M. was able to secure all of them by the following weekend. The scramble, Johnson said, was “miraculous.” Suppliers had to adapt production lines to new specifications; they had to ask their own suppliers to do the same. The most elusive part, a special DC motor, is being shipped from India, where it is being made in a factory that had closed and had to be reopened.
With the parts secured, a G.M. component-manufacturing facility in Kokomo, Indiana, was retrofitted for ventilators. Two hundred and fifty skilled workers, recruited from within and outside G.M., began work after a week of training. A few dozen Ventec engineers are helping run the operation. At stations, each person takes on a sub-assembly task—plugging in a hose, mounting a circuit board with tiny screws—and then passes a bucket containing the incomplete ventilator to someone else. “Because of the urgency and speed, automation was kept down,” Johnson said.
In mid-April, G.M. produced its first five units. Later in the month, the Kokomo plant and its trimmed-down ventilator were approved under an F.D.A. Emergency Use Authorization, and the first shipments were made to hospitals in Illinois and Indiana, at around sixteen thousand dollars per ventilator. (Ford is expected to begin delivering its first Airon ventilators by early July.) G.M. says that it is on pace to produce thirty thousand ventilators by the end of August.
Between the parsimonious minimalism of the Vermontilator and the maximalist ambition of Project Apollo and Project V, some engineers have ended up taking a middle path. In mid-March, at around the same time that Bates connected with Kittell and Silver to develop a prototype of the Vermontilator, Scott Cohen, a co-founder of New Lab, a center for researchers and startups in the Brooklyn Navy Yard, began reading up on the global ventilator hackathon. A doctor in Detroit had used a T-tube to split one ventilator among two or four patients. At the University of Florida, engineers were using a sprinkler valve and PVC water pipes to drive what looked like a wheezy bellows. At Rice University, a bare-bones ventilator was being built out of a plastic resuscitator bag and a motor. Groups in Ireland and at M.I.T. were pursuing the same idea—all open source, with instructions and parts lists posted freely online. Cohen, who is not an engineer, turned to friends to help him find a project that New Lab could assist with. One wrote back immediately and said that M.I.T.’s effort was a good bet.
The M.I.T. E-Vent, as the school’s ventilator is known, was based on a prototype that had been created ten years earlier, as a student project in a class on medical-device design. The students’ prototype ran on a battery for three and a half hours, and consisted of a resuscitator bag placed in an enclosure and squeezed by a motor-driven cam. It had a pressure sensor, and settings for tidal volume (squeeze more or less air from the bag) and breaths per minute (squeeze the bag more or less often). The idea had never been developed beyond the class, but it had been revived in early March, and was now being worked on by a team of alumni, professors, and graduate students from the mechanical-, civil-, electrical-, and environmental-engineering departments. The rig had been given to Albert Kwon, an anesthesiologist at Westchester Medical Center, in New York State, who had tested it on a live pig. By Porcine Study No. 4, the device was said to perform comparably to a commercial ventilator operated in a volume-control mode.
The M.I.T. team aimed to build a “reference implementation”—a prototype that proved the viability of its design, which could then be shared for anyone to build. Like other open-source ventilator efforts, it had attracted interest not just from organizations staffed with experts but from amateurs who might try to build a device of their own. “I’m not in favor of this open-source—” Cohen said, interrupting himself. “It’s misleading at a critical time to have people cowboying devices.” He and his friend Marcel Botha, the founder of 10xBeta, a product-design and -development firm in New York, wanted to build the ventilators themselves, or to oversee their production. For a time, engineers in New York and Cambridge worked together; among other things, Botha persuaded Bon Ku, an emergency-medicine doctor at Thomas Jefferson Hospital, in Philadelphia, to loan the M.I.T. engineers one of his hospital’s ventilators, so that they could compare it with their prototypes. But, eventually, the designs “forked,” as often happens in open source.
The New Lab team began calling its device the Spiro Wave, after the Latin word meaning “to breathe.” It has two hundred and fifteen parts; to avoid supply-chain problems, the engineers sourced as many of them as they could from within the state, and persuaded their suppliers to stay open as essential businesses. Under the vaulted ceilings of New Lab’s converted Navy hangar, and, later, at a manufacturing facility operated by Boyce Technologies, in Long Island City, a dozen engineers have been working day and night, in twelve-hour shifts, to perfect the design and solve production challenges. The group has received a ten-million-dollar purchase order from New York City: three thousand units, at $3,333 each. Regulatory experts were brought on to help push through an application for an F.D.A. Emergency Use Authorization. The device—still essentially a pair of robotic arms that squeeze a bag—has a slick metal casing and instructional videos. The Boyce facility is assembling about a hundred units per day.
A similar story has unfolded on the West Coast. On Wednesday, March 11th, David Van Buren, a senior engineer at nasa’s Jet Propulsion Laboratory, began wondering if, under the circumstances, the lab was working on the right projects. He wrote an e-mail to colleagues proposing that perhaps they should be trying to solve the ventilator problem. His idea quickly made its way to the lab’s senior management. “I do space missions,” Roger Gibbs, the deputy director of the engineering and science directorate at J.P.L., told me. “I build things and we send them to other planets.” By Monday, J.P.L. had also decided to build a ventilator.
At first, the engineers began in the spirit of Apollo 13. “The spark of this idea was ‘Gee, can we at J.P.L. design a ventilator that uses parts scrounged from a garage, or from a vacuum cleaner, or a Home Depot?’ ” Gibbs said. “That idea lasted about six hours.” They next considered developing a reference design and open-sourcing it for do-it-yourselfers. A doctor who had come in to consult waved them off, explaining that his hospital would only use a device that had been F.D.A.-approved. “He dropped a lot of reality on everybody about the level of engineering we’d have to do,” Michelle Easter, a mechatronics engineer who usually works on actuators for spacecraft, said. The doctor explained what a ventilator was: he told them that, if a patient initiates an inhalation, the ventilator must notice; that ventilated air must be delivered at body temperature; that it should be humidified; that it has to provide high concentrations of oxygen. The engineers, working from first principles, peppered him with questions about pressures, volumes, and rates of change. They decided on a new goal: build the simplest possible easy-to-manufacture ventilator, made from readily supplied parts, that was capable of treating all but the most complex cases of covid-19, and get it approved by the F.D.A.
The project unfolded in typical nasa fashion—the gathering of “functional requirements,” the building of increasingly sophisticated prototypes, the holding of team-wide engineering reviews—except over a period of weeks, not years. The team had to adjust to the fact that its design would be produced at volume. “We’re used to having one of the thing, not thousands of the thing,” Easter said. The project had attracted more than a hundred participants, many of whom had never collaborated before. For almost forty days straight, they worked from sunup to sundown—brutal days that were a relief, in their way, from the ennui of lockdown. J.P.L.’s mountain campus, in Pasadena, was mostly empty; on breaks, at picnic tables outside the lab, the engineers watched families of deer graze among wildflowers.
J.P.L. worked up two designs in parallel. One is more portable, and uses an air compressor; it’s in the final stages of testing. The other, like the Vermontilator, accepts air from a wall outlet. vital, as the device is known, operates in a unique “volume targeted, pressure limited, time limited” mode, invented at J.P.L. A clinician can set tidal volume, inspiration-expiration ratio, peep, and breaths per minute. Although it doesn’t have a CO2 sensor or a touch screen, it replicates many of the features of more sophisticated, customizable ventilators; a team of artists and illustrators helped design its faceplate. It is expected to cost between one and two thousand dollars, and its approximately three hundred parts have been carefully chosen to avoid siphoning supplies from medical-grade ventilator manufacturers. vital was tested at the Icahn School of Medicine at Mount Sinai, in New York, on a specialized lung simulator, and has received an Emergency Use Authorization from the F.D.A.; J.P.L. has begun looking for manufacturers.
In software, “feature creep” is the process by which an initially simple program, through the accretion of enhancements, becomes gargantuan, slow, and hard to use. Microsoft Word can take a long time to load in 2020, even though today’s computers are incredibly powerful. The program’s core functions haven’t changed since 1983, but there are many new ones, and many features add complexity beyond themselves. If you want your program to have both an Equations Editor and Track Changes, then you must teach it to track changes to equations. Even the Undo function is a complex subprogram worthy of several full-time engineers: it must be able to undo not just typos but table reformattings, image resizings, and comments that have been added during a review session.
One wouldn’t want to accuse a ventilator of feature creep, since each new feature has the potential to save lives. But a ventilator’s complexity also expands nonlinearly as the number of parts, sensors, and functions grows. The problem is especially acute because medical devices must clear a high set of regulatory hurdles. As devices grow more capable, and more complex and expensive, they require more careful regulation. This dynamic, which is acceptable during peacetime, might seem counterproductive during wartime. And yet the devices must still work, sustaining patients, sometimes for weeks, without glitches or failures.
The Vermontilator is as simple a ventilator as could be imagined: the first prototype had seven parts. Even so, most of the team’s time has been spent adding safety valves, pressure regulators, and alarms—safety features required for an F.D.A. Emergency Use Authorization. The M.I.T. E-Vent and the Spiro Wave are more complicated. No one working on the problem envies anyone else’s chosen point along the complexity curve. “That might be O.K. for a very short-term stopgap measure,” Bates said, of the bag-based models. “But you could not have, generally speaking, someone with bad covid lung injury on one of those things for hours or days, because you would destroy the lungs.” In turn, M.I.T. engineers, when hearing about some of the more amateurish bag-based projects, shake their heads. Some respiratory experts insist on the value of top-tier ventilators; a doctor might find the CO2 sensor indispensable, or argue that she’s seen patients’ respiration improve when they’re moved from old, stockpiled ventilators to newer ones. “We’ve been amused at what people have been inventing as solutions,” Sharon Einav, the I.C.U. specialist in Jerusalem, said. “It’s like someone giving you a Fiat Punto when you normally drive a Ferrari. But we’ve not been in a situation where we’ve had to triage patients.”
When the Spiro Wave was first imagined, in early March, there were fewer than a thousand confirmed coronavirus cases in New York. By the fourth week of March, there were twenty-six thousand. Ventilators were being sought from innumerable sources: Chinese philanthropists, the governor of Oregon. According to the Times, New York State awarded an eighty-nine-million-dollar contract to Yaron Oren-Pines, a Silicon Valley engineer with no apparent ventilator expertise, who claimed that he could supply the machines; none were delivered. (State representatives said that they were acting on the advice of the federal government.) To insure an adequate supply of ventilators, some hospitals began experimentally upgrading or modifying some of the other breathing devices that they had on hand. In early April, Cohen hosted some I.C.U. doctors at Boyce Technologies, where the Spiro Wave was being manufactured. “These guys were beat to shit,” Cohen said. “They looked at the devices. . . . They were just, like, ‘We need this, guys.’ They just looked us all in the eye. ‘When can we get it?’ ” Cohen’s team said that the ventilators could be ready in four or five days; in the meantime, the engineers would work to polish their design.
By the time the Spiro Wave was ready for production, however, cases in New York had begun to decline. The nightmare scenario—doctors triaging patients, providing ventilators to some but not others—never came to pass; on the other hand, many people died outside hospitals, at home or in nursing homes, without ever being put on a ventilator. Officials are still trying to get an accurate count of deaths caused by covid-19. Almost certainly, when such non-hospital deaths are included, the count will jump significantly.
There is a difference between holding on and having enough. The climactic language we have adopted during the first phase of the pandemic—waves, surges, peaks—may be misleading. The emergency continues. As locked-down cities open up, the virus will likely infect new people, many living in places without the health-care resources of big cities like New York and Seattle. “When I hear New York talking about the fact that they are down the backside of the mountain, I know they have been through hell,” Michael Osterholm, the director of the Center for Infectious Disease Research and Policy, at the University of Minnesota, said last month. “But they have to understand, that’s not the mountain. That is the foothills. They have mountains to go yet. We have a lot of people to get infected before this is over.” G.M. and Ford are still aiming to contribute to the Strategic National Stockpile, a bulwark against second waves in major cities and a surge in rural cases. Spiro Wave is turning its attention to global distribution; Cohen and his team have been talking with leading health-care professionals in Ethiopia. “Those in the Southern Hemisphere are only just starting to feel it,” he said.
In Vermont, hospitals have avoided becoming overwhelmed, and the curve has flattened. But Bates and his team, who anticipate receiving F.D.A. approval soon, are negotiating with the state for a purchase order. The team is contemplating a “Mark II” Vermontilator, which would still deliver A.P.R.V. but with more customizable settings. Bates recently received an e-mail from someone who works with the World Bank in the Central African Republic—a country of more than five million people, with only three ventilators. “That opens up a whole new potential for us,” he said. (In addition to ventilators, of course, the country would need clinicians with the training to operate them.) Whatever the result, he continued, the Vermontilator project has enabled him “to work with people at a level of intensity that would never have been possible without this crisis. And so you find out just what is possible.”
The missions have launched, destinations uncertain. No one can say for sure where or when the ventilators will be needed; no one knows which design is best or more cost-effective or reliable. Researchers are still trying to figure out how the virus does its damage. “If you don’t understand the illness,” Einav said, “even the most sophisticated ventilator is not going to work.” Doctors treating covid-19 are exploring ways to avoid intubating patients for as long as possible, using different equipment and techniques to support failing lungs. The month of March—when the official case count began skyrocketing in New York, and when ventilator projects at the University of Vermont, M.I.T., New Lab, Ford, G.M., and nasa began—already seems like the distant past. But building quickly, in advance of a murky future, may be what we need to do in a pandemic. On Friday, March 13th—the same day Bates got the text message about A.P.R.V.—Michael Ryan, the executive director of health emergencies at the World Health Organization, described the most important lesson he’d learned while fighting outbreaks of Ebola. “Be fast. Have no regrets,” he said. “If you need to be right before you move, you will never win.” ♦