Photo: David Dee Delgado/Getty Images

We are, finally, beginning to see some real plans from people with the power to enact them. On Tuesday, California governor Gavin Newsom unveiled a sort of road map for a gradual “reopening” of the state — including benchmarks for testing and hospital capacity, and continued social-distancing guidelines and even temperature checks. A handful of serious, sobering national proposals have been put forward by think tanks and the like in the U.S., and the White House has produced a set of guidelines to govern a gradual, region-by-region pullback from full-economy quarantine. In Germany, Chancellor Angela Merkel announced a similar blueprint (and gave a memorable illustration of the terrors of exponential growth in a pandemic). Coming alongside news from hot spots like New York that new hospitalizations and even deaths may be plateauing or even declining, the plans are a little flicker of light at the end of the quarantine tunnel. Indeed, over just the last few days, Americans have grown less worried, and more optimistic, about the coronavirus pandemic.

But getting out of the lockdown — and out of your shelter-in-place bunker — is not the beginning of the end of the pandemic. It is only the end of the beginning — the very brief beginning of what seems likely to be an epically long saga of disease, fear, and uncertainty.

There are, practically speaking, three paths out of the coronavirus crisis, to a way of life that resembles the one interrupted by COVID-19. The first is a vaccine. The second is effective treatment for the sick — not just effective at the margin, but so effective that catching the disease becomes a considerably less worrisome prospect for even those with comorbidities. The third is through herd immunity, when enough of the population has acquired COVID-19 antibodies that even with a return to “normal” life, there wouldn’t be enough opportunities for disease transmission for the virus to continue circulating through the population.

You have probably heard quite a lot in the past few weeks about testing — in particular the need to deploy widespread testing and possibly what’s called “contact tracing” alongside it, to identify not just those who are sick but those they’ve been in contact with, as well. But a widespread testing regimen — or those “test and trace” programs — isn’t a path out of the pandemic, only out of lockdown. It doesn’t bring us clear of the disease, it is simply a method of waiting in relative safety and security, allowing us to live somewhat more openly, though still under the ever-present threat of infection, until the arrival of one of the other three end points.

Here are the timelines for each of the three. The most optimistic projection for vaccines is that they begin to be available this fall; other reputable estimates suggest between one and two years from now. A two-year development cycle would be unprecedented speed for any vaccine, and, while scientists are quite optimistic, no vaccine has ever been developed for a coronavirus before; onto each timeline you’d have to add some amount of time for rollout and administration.

The treatment picture is murkier, but the drugs being tested today are repurposed ones, not designed to combat COVID-19 but deployed on the chance they might help. One in particular, remdesivir, is showing some real promise, but in general it is hard to bet confidently on repurposed drugs to be miracle cures of the kind that dramatically change the clinical shape of the disease and its treatment. Serological treatments offer some promise, but testing is only in the earliest stages. And the drugs likely to really “cure” the disease are just notions in a lab, at this point.

That leaves herd immunity. Epidemiologists tell us it requires between 60 to 80 percent of the population to have antibodies. At the moment, though, lack of testing means we don’t have a clear picture of the spread of the disease; a generous rough estimate for how many Americans have been exposed is 5 percent. While there are some reasons to hope that the exposure could be significantly higher, 5 percent would be more than ten times higher than the number of known cases, and would be in line with large-scale serological surveys in Holland (where the disease has been relatively widespread), suggesting that 3 percent of the population had antibodies. Others projections suggest that the U.K. is only 5 to 6 percent through the course of its pandemic, and recent models estimate an immunity level of about 6 percent across seven European countries. And it means, taking that generous figure for disease exposure and the low-end threshold for herd immunity, we would need 12 times more exposure than we’ve had to this point — in other words, that we are only one-12th of the way through this crisis.

That may sound bleak, and there are some indications that the population spread could be much more broad. But assuming no wild underestimate of total asymptomatic cases, one-12th of the way through the crisis is a very optimistic projection, if not quite a best-case scenario. It is possible that even less of the public has been exposed — perhaps one percent or lower. At that level of exposure, we could be only one-80th of the way through the pandemic, requiring 80 times more infection and exposure to attain herd immunity than we have had to this point.

Now, disease spread is not linear, which means 80 times more exposure doesn’t necessarily mean the pandemic has to last 80 times as long as it already has. But it does mean, probably, that to reach herd immunity many, many more people will have to get sick — some of those very sick, and some of those lethally so — before we find ourselves, in any meaningful way, in the clear. And in flattening the curve to limit the burden on hospitals and health-care workers, we have slowed, rather than accelerated, the exponential spread — that is why the charts of new cases, new hospitalizations, and deaths are all looking relatively encouraging lately. This is, inarguably, a good thing — it has allowed us to avoid the enormous amount of suffering that would have come about if our health-care capacity was breached, with health-care workers needing to triage their equipment and attention and simply abandon some patients to die without proper care, as they had to in Italy. But while we seem to have avoided that tragedy, and that horror, enough to peek forward and see the possibility of life after quarantine, that isn’t the same as saying we are on the other side of this. In all likelihood, we have a very, very long way to go. On April 14, in the journal Science, Harvard researchers suggested the epidemic could last through 2022 — not just into the fall, and the election, but all the way into the midterms.