Coloradans are moving around at nearly pre-pandemic levels. Will a second coronavirus wave follow?

In Larimer County, as June barrels into July and Colorado nears the end of its fourth month mired in the coronavirus pandemic, Colorado State University professor Jude Bayham has noticed a trend: There are a lot more people visiting restaurants than there were in April and May.

This observation comes not so much from his personal life as from his professional one. Bayham is an economist who studies “avoidance behavior” — how people respond to known risks. During the pandemic, he has become one of the experts looking at mobility data for the state’s epidemiological modeling team, the group that is creating predictions about how the virus will spread so that policymakers like Gov. Jared Polis can decide how to respond. Bayham charts these mobility numbers on graphs comparing them to mobility patterns from 2019.

And what he has seen in the last couple of weeks is clear. Coloradans across much of the state are almost back to moving around at pre-pandemic levels. At restaurants, salons and clothing stores, Coloradans in many counties are approaching near-normal levels of activity.

“There is clearly an increase in these mobility measures, however you want to cut it,” Bayham said. “People are spending more time out in public.”

The trend comes as Colorado increasingly allows the reopening of businesses seen as among the riskiest for spread of the coronavirus — places like casinos and bars, both of which are now able to operate at limited capacity.

And it also comes as states that began reopening their economies around the same time as Colorado are seeing worrying spikes in COVID-19 cases. In a recent Twitter thread, Andy Slavitt, the former Obama administration health official who has become a wonky celebrity for his nightly pandemic summaries, lumped Colorado with 13 other states in a group he called “the rabbits” — the states that reopened first. Through mid-June, the rabbits had seen a 26% increase in case growth, he wrote. Only two states in the group — Colorado and Indiana — had defied the trend and seen their daily case numbers decline.

On Friday, Dr. Rachel Herlihy, Colorado’s state epidemiologist, said health officials here are watching case spikes in neighboring states like Arizona and Utah warily.

“The modeling data has been quite favorable” in Colorado recently, she said. “But we certainly are being cautious. We know from the experience of those states … that we’re really dependent on human behavior.”

An outbreak last week of more than 100 new cases in Boulder tied to University Hill parties and anti-racism protests has pushed Colorado’s numbers slightly higher in recent days and shows how quickly the virus could surge anew.

But, when the state released its daily case counts Friday, the numbers continued to show good news overall. Hospitalizations for COVID-19 have dropped to their lowest number since March. The rate of people testing positive for the virus remained below public health benchmarks.

So, as Colorado continues to reopen while avoiding a second wave of the virus, it raises a question: Are we actually good at coronavirus life or are we just lucky?

“I think we’re both,” said Dr. Mark Johnson, the executive director of Jefferson County Public Health. “And I think we don’t know the answer to that question.”

Staying at home is not the only answer

Experts say that people moving around more is not necessarily a bad thing. It’s all about how people move around.

“It doesn’t matter so much what the government does in terms of relaxing stay-at-home measures if people are still adhering to the guidelines,” said Dr. Eric Toner, a senior scholar at the Johns Hopkins Center for Health Security in Baltimore. “If people are wearing masks and maintaining social distance, then you wouldn’t expect to see a huge increase in cases as things reopen.”

“So it may be,” Toner added, “that Coloradans are just really good people and are following advice.”

Bayham, the CSU prof, agreed that could be the case. The mobility figures he looks at only capture where people go and for how long. They don’t show what people do when they get where they are going.

The data are collected from a sample of mobile devices — smartphones, mostly, but also smart watches and similar gear. The figures are anonymized, meaning they are stripped of identification information, and then they are also aggregated at the census block level. Bayham said he can’t track any individual person’s movements — nor does he want to. The value is in the big picture.

Early on in the pandemic, Bayham said the connection between mobility and viral transmission was really clear. The more people moved around, the more the virus spread.

But, after a big crash in mobility around the time Polis issued the statewide stay-at-home order, the state has actually been seeing increasing mobility since late-April, Bayham said. And, this time, increased movement didn’t closely correspond with increased viral transmission.

Bayham said this is likely because people in Colorado are venturing forth into a changed world. They are more cautious. The places they are visiting are cleaner. Everything is better geared toward stopping the virus.

For instance, while visits to restaurants have almost returned to normal in many places, Bayham said it’s possible that the visits now are mostly quick stops to pick up takeout — as opposed to longer visits for eat-in dining, pre-pandemic. (He hopes to dig deeper into this question soon.)

“You can think about these mobility patterns as a pre-condition for transmission,” Bayham said. “It’s necessary for transmission to occur. But just because people are in a place where the virus is present is not sufficient for transmission.”

The mask factor

Toner said the states that haven’t kept control of the virus after reopening have a few things in common. They tend to have weaker health systems where many people struggle to access care. While Colorado has specifically tried to get coronavirus testing sites into underprivileged communities, other states have not.

And Colorado’s weather also may play a factor, Toner said. We are a state that generally goes outdoors in the summer instead of huddling inside in the air-conditioning to avoid oppressive heat and humidity. The risk of transmission is dramatically lower outdoors, Toner said.

But one trait stands above the rest.

“I think the states that are doing poorly now are the states where their governors have been more relaxed about public health messaging, more eager to open things up, and not strictly adhering to the guidance about the pace at which things should open up,” Toner said.

And a big part of that public health messaging — the elasticized flashpoint in the latest public health culture war — is encouraging people to wear masks. Ever since he donned one at a news conference in the first week of April, Polis has been a frequent and fervent champion of the face mask.

The science on homemade masks and coronavirus is still a work in progress, said May Chu, an internationally renowned disease researcher who teaches at the Colorado School of Public Health. But she said the overwhelming consensus is that wearing masks in public is safer than not.

She put the benefit at a few percentage points of difference. If a person in a given situation has a 25% chance of being infected by the coronavirus, Chu said wearing a mask might knock the risk down closer to 20%. But that’s only if people are also washing their hands and following distancing guidelines.

“If you don’t do all the other practices, it’s probably not statistically significant,” she said.

And homemade masks can actually be quite good. Think of the now-familiar N95 masks as being 95% efficient, she said. The throw-away surgical masks that doctors often wear are about 30% efficient. But a homemade mask with enough layers of the right material could get to 50% efficiency.

It’s why she’s a big believer that diligent mask-wearing can make a meaningful impact as life returns to normal-ish. And, though she said there is no detailed data on Coloradans’ mask-wearing behavior, she said she’s been encouraged seeing widespread adoption when she goes out in public.

“Within the community, wearing a mask should be a sign of respectfulness,” Chu said. “You are respecting the dangers (the virus) might cause to others.”

Johnson, with Jefferson County Public Health, praised Polis for making decisions based on data and science — including promoting mask-wearing. That doesn’t mean he’s not a little nervous about Colorado’s reopening economy. Johnson said he wished the state had moved more incrementally instead of reopening large chunks at once — which will make it more difficult to know what is to blame if cases spike. 

“It appears that some of the things that opened up quicker were because people screamed the loudest,” he said.

But Johnson also said everybody is learning as they go. And, as the state’s reopening goes right now, it’s so far, so good.

“People are going to be studying this for at least the next 100 years,” he said, “trying to figure out what did we do right and what did we do wrong.”