The US’s new surge in coronavirus cases, explained

America could have prevented another surge in coronavirus cases. It’s now clear it didn’t.

The past week gave America an ugly reminder that the threat of the coronavirus pandemic is far from over. Cases are rapidly rising again. The nation on Wednesday hit a new record for daily new infections, and then hit another record the next day.

There’s some debate about whether this is the “second wave” of infections, or whether it’s a continuation of the first wave that began in early 2020 and never really ended. But what’s clear is the US is now suffering from a rapid rise in coronavirus cases. So far, that’s yet to translate to a rising death toll, likely because rises and falls in deaths tend to lag behind rises and falls in overall cases.

But between Monday and Thursday, the US went from nearly 31,000 reported cases in one day to more than 41,000. Arizona, Florida, Texas, and several other states in the South and West are among the hardest hit.

German Lopez/Vox

President Donald Trump and his allies have suggested that the increase is due to a spike in testing, but the data doesn’t bear that out. The number of cases has increased more quickly than the number of tests, with the percentage of tests that are coming back positive — an indicator of the seriousness of an outbreak — rising above 10, 15, and even 20 percent in some states. (The recommended positive rate is below 5 percent.)

It’s a significant shift from much of May and June, when testing increased, cases plateaued nationwide, the positive rate fell across the country, and it finally looked like restrictions and social distancing measures were working to constrain the growth of the coronavirus.

So what went wrong? The simple answer is states started to relax the restrictions and reopen their economies — giving employers, employees, and their patrons a chance to go back out into the world and interact, fueling new cases.

It’s possible to lift restrictions slowly and safely, and a few states are meeting the benchmarks that experts recommend to do that. But most never fully controlled their outbreaks, instead forging ahead with reopening.

A mix of carelessness and partisanship is to blame. Under Trump, the federal government and some states appeared to prioritize the economy over public health, voicing discontent with the restrictions. Trump called to “LIBERATE” states from shutdowns. Some Americans took up that messaging, reopening their businesses and going back out. Mask-wearing became a politicized issue, and segments of the population rejected face coverings and many other precautions against Covid-19.

The effects were sadly predictable. Citing research on the 1918 flu pandemic and newer studies, experts pointed out that lockdowns worked to slow the spread of the coronavirus, and ending the restrictions would lead to a spike in cases as long as other preventive measures weren’t put in place. But experts’ warnings were not heeded.

“It’s a situation that didn’t have to be,” Jaime Slaughter-Acey, an epidemiologist at the University of Minnesota, told me. “For almost three months, you had opportunities to be proactive with respect to mitigating the Covid-19 pandemic and to help normalize culture to adopt practices that would stem the tide of transmissions as well as the development of Covid-19 complications. … It was not prioritized over the economy.”

The result: America is now in the middle of a predictable, preventable wave of Covid-19 cases — worsening what was already the most widespread coronavirus crisis in the world.

Different states are suffering this time around

In the first wave of Covid-19 cases, the New York City region was the hardest hit, with New York, New Jersey, and Connecticut leading the country in Covid-19 cases and deaths. There were also significant outbreaks in other parts of the Northeast, Michigan, and Louisiana.

The more recent wave has hit the South and West, with cases rising in Arizona (125 percent increase in daily new cases over two weeks), Florida (216 percent), and Texas (174 percent), but also alarming increases in cases in Georgia (103 percent), Mississippi (82 percent), Nevada (104 percent), North Carolina (22 percent), Oklahoma (261 percent), and South Carolina (118 percent). Most of these states have seen their positive rate increase, indicating the rise in cases isn’t just a result of more testing.

German Lopez/Vox

In most of these states, it’s not quite right to say they’re going through second waves — because many of them never really got their first wave under control. Instead, they have seen a steady rise in coronavirus cases, culminating in the exponential growth of the past few days and weeks.

Many states “never got to flat,” Pia MacDonald, an epidemiologist at the research institute RTI International, told me. “That means the states didn’t get to very good compliance with the public health interventions that we all need to take to make sure the outbreak doesn’t continue to grow.”

Arizona, for example, saw a steady increase in coronavirus cases for months before the most recent exponential spike. There was never a sustained decline, as this chart shows:

German Lopez/Vox

While coronavirus outbreaks can be concentrated locally, the current ones appear to cover whole states — with a majority of counties reporting a high number of cases in many states, especially across the South.

This was not inevitable. Connecticut, New Jersey, and New York, for example, all managed to suppress their coronavirus cases after suffering the worst of the pandemic, and have all kept their coronavirus cases down. Others, like Maryland and Rhode Island, have managed to keep their coronavirus case counts suppressed as well.

The difference is that the states seeing the biggest increases were some of the slowest to close down their economies in response to the outbreak and some of the quickest to open back up again. Texas’s stay-at-home order, for example, was one of the shortest in the US — lasting less than a month, according to the New York Times. As those orders have ended, people have trickled out, interacted, and spread the coronavirus. (Since the incubation period can be up to two weeks, there’s a lag between when the virus starts spreading and when cases are reported.)

In some places, the rise in cases appears to be hitting a younger demographic, too. Some Texas and Florida counties, for example, reported that people under 30 made up a growing share — and even a majority — of coronavirus cases.

That’s likely a result of young people being the most willing to go out and about as social distancing ends, perhaps because they perceive themselves as being at lower risk. While young people are at lower risk, and that could lead to a lower death toll from the current wave of cases, there are still plenty of examples of younger patients getting sick, experiencing longer-term complications, and dying.

Relaxed social distancing is likely to blame

Across the board, experts were pretty clear on why states are seeing increases in Covid-19 cases: relaxed restrictions that enforced social distancing.

“The economies are opening up. People are starting to venture out. They’re interacting with others more,” Slaughter-Acey said. “That creates opportunities for transmission.”

The research increasingly shows social distancing measures worked to reduce the spread of the coronavirus. One study in Health Affairs concluded:

Adoption of government-imposed social distancing measures reduced the daily growth rate by 5.4 percentage points after 1–5 days, 6.8 after 6–10 days, 8.2 after 11–15 days, and 9.1 after 16–20 days. Holding the amount of voluntary social distancing constant, these results imply 10 times greater spread by April 27 without [shelter-in-place orders] (10 million cases) and more than 35 times greater spread without any of the four measures (35 million).

The reverse, then, is likely true: Without social distancing measures, places are more likely to see a rise in Covid-19 cases.

That’s what the epidemiological evidence from past disease outbreaks suggests. Several studies of the 1918 flu pandemic found places that took quicker and more aggressive steps to enforce social distancing saved lives. But this research also shows the consequences of pulling back restrictions too early: A 2007 study in JAMA found that when St. Louis — widely praised for its response to the 1918 pandemic — eased its school closures, public gathering ban, and other restrictions, it saw a rise in deaths.

Here’s how that looks in chart form, with the line chart representing excess flu deaths and the black and gray bars below showing when social distancing measures were in place. The highest peak comes after social distancing measures were lifted, with the death rate falling only after they were reinstated.

JAMA

This did not just happen in St. Louis. Analyzing data from 43 cities, the JAMA study found this pattern repeatedly across the country. Howard Markel, an author of the study and the director of the University of Michigan’s Center for the History of Medicine, described the results as a bunch of “double-humped epi curves” — officials instituted social distancing measures, saw flu cases fall, then pulled back the measures and saw flu cases rise again.

As a whole, the US is essentially experiencing that second hump in the epi curve: After states managed to suppress the growth of coronavirus cases with social distancing measures, they eased up, and now cases are on the rise again.

This doesn’t necessarily mean everything has to be shut down again. When the pandemic first hit the US, many states were quick to close down as many public places as possible because there was little understanding of which places were at greatest risk for coronavirus transmission. Now, we have a better — although still far from perfect — understanding of how the SARS-CoV-2 coronavirus works.

For example, outdoor spaces seem to be much safer, with the open air making it harder for respiratory droplets to float from person to person and the warmer weather, humidity, and UV light also potentially playing a role. That suggests that states could probably keep parks, beaches, and other outdoor venues open — as long as people follow recommended safety practices, like wearing a mask and keeping 6 feet from others.

Along those lines, personal precautions seem to be more effective than initially expected. Several recent studies have found masks alone reduce transmission. Some experts hypothesize — and early research suggests — that masks played a significant role in containing Covid-19 outbreaks in several Asian countries where their use is widespread, like South Korea and Japan.

All of that is to suggest that some places, especially those outside, could safely reopen or stay open with the proper precautions.

The key, experts said, is to take the process slowly. States should open things up bit by bit through various phases to see what leads to an unmanageable spike in coronavirus cases and what doesn’t, while building up a public health surveillance system — through testing and contact tracing — that can pick up those increases. Over time, that approach can strike a balance between public health needs and reclaiming some sense of normalcy.

“Since this is new and we don’t have data and experience to guide us, it makes sense to take things slowly,” Lauren Meyers, a mathematical biologist at the University of Texas Austin, told me. “Relax things bit by bit, and see if it’s working. If we relax a few measures, we watch the data for a few weeks; if it’s not going up, maybe we can relax a bit more.”

A key element of this — and one in which states have generally failed — is having a plan to pull back the reopening should things go badly again. “One of the most important parts of this whole reopening experiment is knowing when to slow down reopening based on public health criteria,” Abraar Karan, a doctor at Brigham and Women’s Hospital and Harvard, told me. “It’s why it’s so important to have a public health surveillance system.”

And if things spiral out of control again, a community really might have to shut everything down again to get things under control. “What we want to do is to avoid a situation where the only measure that’s going to turn things around is a full-blown shelter-in-place order,” Meyers said. “However, if we are throwing caution to the wind, and we’re not taking these small steps to protect ourselves, we may find ourselves in a situation where that is the only thing we can do to prevent overwhelming surges in hospitalizations and alarming numbers of deaths.”

It’s not clear what states will do now

At this point, it’s not clear if local and state officials will take the precautions that experts recommend.

The federal government could encourage stronger action. But the Trump administration has largely been absent in recent weeks — stopping daily coronavirus briefings, denying there’s a new spike in Covid-19 cases at all, and generally commenting little on the recent trends. White House guidances have also suggested that the Trump administration wants to leave the bulk of the problem to states, local governments, and private actors.

In some cases, the administration has encouraged the opposite of what experts have called for. Trump has repeatedly pushed states to reopen their economies — in what now was very clearly a premature move. He has also taken bizarre stances, like his remarks that the US should slow down testing and that masks may do more harm than good.

The problem for local and state officials is many of Trump’s supporters and Republicans in general take what Trump says seriously. When Trump downplays the threat of Covid-19 and the benefits of masks, his followers listen — and that likely makes his backers more resistant to their local and state leaders taking aggressive action against new coronavirus outbreaks. In that context, it’s not a coincidence that most of the states suffering the worst now are led by Republican governors.

Then there’s the economy. Although research suggests that getting a disease outbreak under control is ultimately better for the economy in the long term, closing places down now does mean short- or medium-term economic pain. Local and state leaders have to balance those tensions.

Still, things may eventually get so bad that officials feel compelled to act regardless. Following reports of some hospitals in Texas nearing capacity due to a surge in Covid-19, Gov. Greg Abbott moved to slow down his state’s reopening, keeping some businesses at reduced capacity or shut down entirely and closing down bars. (This came after months of Abbott pushing the state to reopen, overruling local governments that tried to stay closed.)

Aside from government action, perhaps people will act on their own. Even after state and local governments moved to reopen, people were at times slow to embrace a rosy view of the situation with Covid-19 and chose to stay home anyway. As people see the effects of the coronavirus firsthand in their communities, they might be driven to strictly social distance again regardless of what their political leaders tell them to do.

How all of these factors could come together, from individual decisions to government actions, will decide just how bad and long-lasting this new spike in coronavirus cases is. But some of the surge, experts said, is already baked in — it’s likely going to take weeks for new measures, should they come, to take effect and start leading to a drop in Covid-19 cases.

“We have to start putting on the brakes long before we get to hospital capacity,” Meyers said. “New York threw on the brakes in mid-March. It wasn’t really until early or mid-April that deaths finally reached their peak and started subsiding. You can put on the brakes today, but you won’t see the impact until several weeks out.”

That’s why it was important to act before the situation got to this point, and why it was so dangerous for officials to relax social distancing measures before Covid-19 cases began to fall. Several states are now seeing — and will continue to suffer from — the consequences.

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