By Brandi Greenberg, Vice President, Life Sciences and Ecosystem Research

Let's try this again.

Last month, I explored one of the most common questions of 2020 (and 2021): "When will life get back to 'normal'?"

While I couldn't suggest a specific date when normality will return, I used my background researching the health care industry to identify three distinct scenarios—the "good," the "bad," and the "ugly"—and offered probabilities for each one based on the best available data I had at the time. But a lot has changed in four weeks. We've seen promising new data about vaccine efficacy; we've seen more viral variants take hold; and just last week, we saw a third vaccine receive FDA authorization for use in the United States.

So, it's time to revisit those original scenarios and the assumed probabilities of each. As I noted in February, even though I embrace the fluidity of these predictions, I still think there's value in "gut checking" where we are now and where we could end up later this year—and considering how health care stakeholders should prepare.

The 'good' scenario: America achieves herd immunity by summer, primarily via vaccinations

As I mentioned last month, we must first acknowledge a painful truth—there is no "good" outcome in a pandemic that has already killed more than 510,000 Americans and has exacerbated severe health disparities.

Yet in the last few weeks, we've seen vaccination rates go up, case rates come down, as well as several new deals that will expand vaccine manufacturing capacity. These trends all make me increasingly optimistic that a "good" future could be awaiting us—at least in the United States, where I'm most familiar with the state of affairs.

The U.S. Covid-19 vaccination scenario planning guide

There are a few reasons to think this scenario is likely. First, our supply of vaccines is rapidly expanding. In fact, Biden just announced that the United States will have enough vaccines for every American by the end of May, rather than the end of July, as originally promised. How have we made such strides so quickly? FDA just last week authorized Johnson & Johnson's (J&J) single-shot vaccine; the company said it can deliver an additional 20 million doses in the United States by the end of March, and 100 million doses by the end of June. It's unclear to what degree J&J's newly announced manufacturing partnership with Merck will impact domestic supply, but it's safe to say it will likely help. In addition, Pfizer said it can increase supply of its vaccine from 4-5 million doses per week to 13 million doses per week by mid-March, and Moderna said it can double its supplies to provide more than 40 million doses per month by April.

Second, the pace at which we're getting shots into arms is accelerating. 78.6 million vaccines have already been administered in the United States–at a rate of 1.94 million doses per day. Governments, providers, and pharmacies are improving their supply chain logistics and coordination efforts to more efficiently and seamlessly roll out the vaccines. In addition, states are quickly moving through different phases of prioritization and eligibility. For example, New York, California, and Washington D.C. now are administering vaccines to people with underlying conditions and comorbidities. And several are prioritizing teachers and child-care workers, in the hopes of accelerating timelines to resume in-person teaching. Additionally, new supply chain advances will help expand access and ease storage requirements. For example, Pfizer's vaccine can now be stored at normal freezer temperatures for five days, and J&J's vaccine can be stored at normal refrigerator temperatures for at least three months. Importantly, the Biden administration, local municipalities, and provider organizations have expanded efforts to improve access to vaccines for underserved communities and launched targeted campaigns to combat vaccine distrust—hopefully leading to more equitable vaccination rates nationwide.

Third, we're also learning more about the vaccines that give me additional confidence in their safety and their efficacy. New data from Israel and the United Kingdom provide the first real-world evidence confirming that Pfizer's vaccine is nearly as effective in the real-world as it was in clinical trials. Data also shows that Pfizer's vaccine is 75% efficacious after one dose, and people who already had Covid-19 might only need one dose. While it's too early to know whether this will cause governments to update their prioritization criteria or recommended dosing protocols, the new data nevertheless should build confidence that these vaccines are safe and effective.

We're also learning that even if new coronavirus variants are able to infect vaccinated patients, our existing vaccines still seem to prevent Covid-19 from turning deadly. As the New York Times has reported, of the 75,000 patients who received the five major vaccine candidates in clinical trials—including studies in the United States, United Kingdom, Brazil, and South Africa—not a single one has died from Covid-19.

Fourth, new vaccines are likely coming. We've seen promising—if incomplete—data from Novavax, AstraZeneca, and CureVac/GSK on their vaccine candidates, which (like J&J's vaccine) are easier to distribute than Pfizer's and Moderna's mRNA-based vaccines.

Fifth, the grim truth is that more people are acquiring some degree of natural immunity (if limited) from coronavirus infections. So far 28 million Americans have tested positive for the virus, and some experts believe multiple times as many were infected without a confirmatory test. Nobody knows exactly how long their immunity will last, but they're a growing population with at least some protection.

Finally, spring is coming, and cases are already starting to decline from the winter surges. This seasonal effect, when combined with rising vaccination rates, could cause infections to plummet. That, in turn, would reduce hospital and ICU occupancy rates, which would help providers deliver top-quality care to each patient, further reducing death rates.

This increasingly optimistic scenario is reflected in updated projections by the well-regarded Institute for Health Metrics and Evaluation. It projects that daily deaths will decline from their peaks by about 90% by June.

For all of these reasons, here's my updated thinking about the likelihood of a "good" scenario.

• What defines a "good" scenario? To my mind, a "good" scenario means death rates decline by 90% or more by summer and that herd immunity—perhaps with help from continued masking or social distancing—prevents a major surge in deaths next winter. Outbreaks could still emerge among undervaccinated populations or geographies, but these flare-ups would be far smaller than this winter's epidemic.

• What are the odds? This, I think, is more likely than many people believe. I'd now put the odds at 65%, notably higher than I estimated last month.

• How can health care stakeholders prepare? If the U.S. health care system is flooded with newly authorized coronavirus vaccines, our core challenge will be getting those vaccines into people's arms quickly. Our Covid-19 Vaccine Scenario Planning Guide can help you do that. You'll also need to address vaccine misinformation, as well as meaningfully engage with communities who have deep-seated, and historically well-deserved, mistrust of the health care system.

The 'bad' scenario: America achieves herd immunity in late 2021, in large part due to new infections

America is likely to achieve herd immunity in 2021. The difference between a "good" and a "bad" future is largely about how we get there and how long it takes.

Specifically, in a "bad" scenario, tens of millions of additional Americans will gain immunity the hard way: by contracting Covid-19, with all the morbidity and mortality risks that entails. Of course, we still don't know how long that type of immunity will last, especially as new viral variants take hold.

Why could this happen?

On the vaccine front, it's easy to imagine why progress could stall. Perhaps new data reveals existing vaccines (and boosters) are less effective than expected against new variants. Vaccine uptake may stall out too soon, with 30+% of the adult population holding out against getting a shot. Either option leaves aa sizable portion of the country still prone to new infection, hospitalization, or death. And we could also learn that vaccine or infection-induced immunity may be short lived.

Perhaps new data halts—or even reverses—the authorization of pending vaccine candidates. Or perhaps Moderna, Pfizer, or J&J, encounter major manufacturing problems, or no vaccine is ever authorized for children or pregnant people. While some clinical trials involving pregnant people are in the works, vaccine trials for teens and children are moving slower than anticipated. Since children make up about a quarter of the population, and we know they can transmit the virus, further delays in child/teen eligibility could definitely slow our pace toward herd immunity.

These risks are all possible. But if there's a reason for optimism, it's that the number and variety of vaccine candidates under development—as well as the number of companies helping out with manufacturing and distribution—creates resilience against any single failure. In other words, for America's vaccination strategy to fall apart, multiple things likely would have to go wrong.

A separate—and to my mind bigger—concern is that the coronavirus could spread more rapidly than previously projected. This is, in fact, already happening, as more infectious variants that originated in the United Kingdom, Brazil, and South Africa, California, and New York are spreading across the United States. Just this week, Houston became the first American city to record cases of every major Covid-19 variant, and experts are projecting a potential surge this month related to the variant originating in the United Kingdom. And as I mentioned above, without approved vaccines for children (and parent willingness to have their children vaccinated), the virus could continue spreading and mutating faster than our vaccination programs can keep up.

Worryingly, this spread in variants could coincide with governments and individuals prematurely relaxing preventative measures like social distancing and masking as vaccination rates increase and the weather warms up. Already we've seen Texas and Mississippi lift masking requirements and capacity constraints. Since we still don't know enough about how the vaccines impact transmission, this could lead to an uptick in the spread of the virus.

If these new variants spread faster than vaccinations can occur, then 2021 could be a very difficult year. Further, if the coronavirus becomes more infectious, it would become harder and harder for the United States to achieve herd immunity, since the virus would remain capable of spreading, even with fewer vulnerable targets.

This is the possibility triggering lots of conversation and speculation among my peer group, and it makes the "bad" scenario feel frighteningly plausible, even if it's still unlikely.

• What defines a "bad" scenario? I'd consider a "bad" outcome to mean: (1) Coronavirus variants drive a new surge in U.S. cases this spring, and we experience infection and death rates that markedly exceed their January peaks; and/or (2) a significant portion of the public remains unvaccinated by fall, and Covid-19 surges as the weather cools.

• What are the odds? I'd estimate a 15% chance—lower than my estimate from last month, for the reasons I've outlined. (I'd put higher odds on what we might call a "mixed-bad" scenario, where certain populations receive the vaccine more slowly, leading some communities—especially historically disadvantaged ones—to experience a "bad" future even as others see "good" outcomes.)

• How can health care stakeholders prepare? This scenario implies high ICU occupancy rates across the next few months, plus the possibility of significant surges next winter. To keep hospital beds available for those who most need them, it will be critical to ramp up hospital-at-home care.

The 'ugly' scenario: Vaccines falter, and America doesn't achieve herd immunity in 2021

The defining characteristic of an "ugly" scenario is that America fails to achieve herd immunity in 2021. This could occur if existing vaccines and boosters don't effectively protect against new coronavirus variants, or if the immunity conveyed by infections or vaccinations fades quickly. (We're already seeing signs of this risk in South Africa, where a new variant is reinfecting people who've already had the coronavirus.)

Even if the existing vaccines and boosters do work well enough to protect against new variants, the global supply is still insufficient, and we're nowhere close to having global herd immunity. In this analysis we've focused on when life will return to normal in the United States, but the reality is that the wellbeing of other countries directly impacts ours. The longer Covid-19 goes unchecked in developing nations, the greater the opportunity exists for newer, more potent variants to develop—potentially ones that are resistant to current vaccines. And as long as our borders are open, those variants will make it into the United States. Not only will this directly impact people who aren't vaccinated for a range of reasons (e.g., immunocompromised patients, children, pregnant people), but the industry will be continuously playing catch up to develop effective boosters for those already vaccinated.

In this scenario, 2021—and even 2022—could look a lot like 2020.

We could see new rounds of stay-at-home orders and lockdowns, more stringent than any put into place since April 2020. The U.S. economy, which so far has been buoyed by hopes of a rapid bounce-back from the epidemic, could crater. A slim Democratic majority in Congress may struggle to pass relief packages, amplifying the suffering. The failure of early vaccines could lead to a resurgence of vaccine skepticism.

Further, there's suggestive evidence that some of the new coronavirus variants might cause more severe symptoms, which could further overwhelm hospitals and ICUs and cause hundreds of thousands of new deaths. And many people, after years of arranging their lives around an epidemic, could simply give up on social distancing, driving even more infections.

In this scenario, the coronavirus could even become an endemic human disease—the sort of durable, deadly pathogen that wealthy nations haven't dealt with since the middle of the 20th century.

Eventually, our institutions would adapt, and we'd get better at both preventing spread and treating people who become infected. But make no mistake: This is a grim future to imagine.

• What defines an "ugly" scenario? We'll know we're in an "ugly" future if we find it's impossible to achieve herd immunity with current vaccines—whether because our vaccines don't protect against new variants or vaccine-induced immunity fades more quickly than we can vaccinate the public.

• What are the odds? It's difficult to say, since the risk depends on impossible-to-know variables such as how quickly variants evolve and whether they develop vaccine resistance. My best guess, however, is 20%—higher than my estimate from last month. Ultimately, if things don't go well, they're likely to go downhill in a very significant way.

• How can health care stakeholders prepare? Because an "ugly" scenario could take so many forms, the best way to prepare is to increase your organization's overall resilience. Get ready to boost your surge capacity. Ensure you're ready to meet PPE needs. And make sure you can recognize, and address emotional distress in your staff.

We will live in the future we build

One final thought. For most of this post, I've framed Covid-19's course as something that will happen to us. The world will hand us a good, bad, or ugly future, and it'll be up to us to respond accordingly.

But as anyone who knows me will attest, I'm inherently an optimist at heart. And my optimism comes from a belief in human ingenuity and resilience—and a choice to focus on the things we can control. As people who work in the health care industry—and as members of a shared human community—we absolutely have a role in shaping our future. So I'll close with the same sentiment as I shared one month ago: if we do everything we can to ramp up vaccinations, to engage and overcome vaccine hesitancy, to recognize and contain the spread of Covid-19, and to make social distancing and mask-wearing easier and more acceptable in our communities, we can nudge the course of the epidemic in a more hopeful direction.

A "good" outcome isn't guaranteed, but it's a real possibility—and it's at least partly in our control. We all just need to do our part to bring it about.