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Is The Strip In Danger of Super-Spreading Covid-19? A Contact Tracing App May Be The Answer

Five months into the pandemic and we’re still figuring out how to stem the spread of COVID-19. 

However, this week marks a milestone: the release of a contact tracing app that helps notify users if they’ve been in proximity to people who have tested positive. 

This raises some questions, such as: Where are people most likely to be exposed to the virus? Many health experts are saying it’s family and friend gatherings. 

And some are also saying it’s the Strip, where most resorts are open to travelers. It’s inspired a number of media reports that paint Las Vegas as a potential super-spreader city.

So, would a contact tracing app help reduce that grim prospect?

Nevada Independent health reporter Megan Messerly has been crunching infection numbers and covering the major developments of COVID-19 since the start of the pandemic.

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She has also been looking into the new app called COVID Trace Nevada.

"The basic premise of contact tracing is that you're trying to find everyone who an infectious person has come into contact with," she said.

Messerly said contact tracing is used for other types of infectious diseases, including measles, tuberculosis and sexually transmitted infections, but it is being used now to find people who have come into contact with people with coronavirus.

The efforts are underway both by state and local health officials. When someone tests positive, they are asked who they've come in contact with, then contact tracers call those contacts to let them know they need to be tested and monitored for symptoms.

However, she said the success of the program has had varying degrees of success because of a backlog in July.

The state hopes the new app helps the process along.

Messerly explained that Apple and Google started developing the technology to make the app work in the spring. 

It works with a phone's Bluetooth capabilities. Recent updates have put the technology into a phone's operating system but the phone users must download the app and answer a series of security questions to turn it on.

"Essentially, what happens when your phone comes into contact with another phone, your phones actually exchange these anonymous tokens via Bluetooth," she said, "So, it's not telling you your name or anything about you, it is just exchanging these anonymous identifiers."  

That information can be used to contact trace, later on, she said.

So, if someone gets a positive test result, he or she is given a code by the Southern Nevada Health District to put into the app. The app then notifies any other phone it has exchanged tokens with in the last 14 days, which is the incubation period for COVID-19. 

It also uses a complex algorithm to determine if the closeness of the contact, using the 15 minutes within six feet perimeter, is enough to trigger an alert.

Messerly noted the app is generally going to detect a positive exposure between people who have had close contact with others, not people who are just passing by. 

"The app does not work in such a way that if you're wandering around in the grocery store, you're going to be getting pings saying, 'Hey, there is someone 15 feet away from you who has COVID-19.' It doesn't quite work like that," she said.

As far as privacy concerns, Messerly said the app uses phone-to-phone Bluetooth technology - not the internet. It doesn't store personal information like your name or address; the token or code your phone is given is individual to you, and it is not based on location, like some dating apps. 

Plus, you can delete the app at any time. 

The bigger concern for health officials is getting enough people to use the app to make it useful.

"That is why the state is trying to get buy-in from as many individuals and have businesses encourage their customers to download the app as well because it just won't be effective if you're not using it," she said.

Messerly said Jim Murren, the head of the state's COVID task force, is working with hotels to have them encourage guests to download the app while staying in Nevada.

"I think the hope is that most - if not all the resorts - will be encouraging visitors to download this at check-in," she said.

She said hotel registration agents may ask people to download the app or give them written information about how the app works.

COVID Trace Nevada only works within Nevada, but if a visitor returns home and tests positive for the virus, they can submit that information.

Contact tracing is extremely time-consuming. It can take hours to track down and talk with one person's contacts, said Marshall Allen, a health reporter for ProPublica.

He said the app could help speed up that process. 

Allen recently published an article outlining the concerns public health officials have about Las Vegas as a super-spreader city.

"When I talked to public health experts, all of them that I talked to said a place like a Las Vegas casino would be a real potential hot spot for transmission of COVID-19," he said, "I mean you have an indoor environment. You have people from lots of different places mingling together. The use of masks and social distancing might be more hit and miss. And people might be more prone to higher risk behavior, just by the fact that they're in Las Vegas in a pandemic."

The biggest concern is that people come here from across the country, mingle and then return home.

In Allen's report, he used the data from thousands of cellphones that had been on the Las Vegas Strip during a four-day period in July. The data was gathered from fitness and weather apps that use location data.

The data did not include personal information and the gathering of the information complied with privacy laws.

The analysis found that the people on the Strip in those four-days returned to all the states in the U.S. mainland, except Maine. 

"What the data shows, I think, the value of that analysis, is just showing how interconnected the country is and showing what a hub of travel Las Vegas happens to be," he said.

Allen emphasized that his analysis did not show that those travelers contracted the virus or that they were associated with the spread of COVID-19.

"You can't tell that those were all tourists," he said of the analysis, "You can't tell who those people were, but they spent some amount of time on the Las Vegas Strip, during those four days, and then they reached all over the mainland United States in that same time period and we don't really have any system to tell whether or not that is contributing to the transmission of COVID-19."

Brian Labus is an associate professor at UNLV's School of Public Health and he is not surprised by Allen's research.

"We're talking about an environment where a lot of people come together from all over the country and potentially aren't following the rules they need to follow to protect themselves. There is that potential for spread," he said.

Because of that potential, there has been a push to get health officials to release more information about possible clusters and outbreaks.

Labus sits on the state's medical advisory team. He said the problem with releasing information about where someone might have contracted COVID-19 is that it's difficult to tell if someone did get the virus at a specific location.

"Just because someone reports visiting a certain place, doesn't mean that's where they were infected," he said, "So if I went down to the Strip tonight and stayed at a particular casino for a couple of hours and then tomorrow got exposed and was infected, those things would all be in that investigation."

Labus said just because he visited a casino doesn't mean he got it there.

That kind of investigation is called case investigation and it is an important part of the process, he said. The new app released by the state goes in the opposite direction - it looks forward to stop the spread.

"The whole point of contact tracing is interrupting the chain of transmission, starting with the person who has already been infected," he said.

Labus said the process allows health officials to quarantine an infected person and potentially the people he or she has been close to. 

Samuel Scarpino, an assistant professor at Northeastern University’s Network Science Institute, agreed that contact tracing is vital to stopping the virus' spread; however, he does think that providing information about clusters in certain places would be helpful.

"I certainly understand the concern on the part of the casinos, which is if there isn't good evidence that there's transmission happening at the casinos, there will be a likely economic hit to them if there is data being released that potentially there is transmission," he said.

But he also believes if people have accurate risk information, they will act on that information. So, if casinos aren't sites for super spreading the disease, people will feel more comfortable going. 

And if they are, better safety precautions can be taken.

The new app is just one of the state's efforts to try to come to grips with the pandemic, Scarpino believes one national direction at the beginning of it all would have helped. 

"I think that is one of the big issues with our response, both nationally, but really even at many of the state levels, that there's been this kind of scattered response, and in some ways, that's given us kind of the worst of both worlds. We've had a lot of economic effects. We've had a lot of effects of the virus, but unlike many other countries, we didn't get the virus under control, which means we're not really able to safely reopen." 
 
He said the scattered approach has been worse for the control of the virus than a less restrictive but more uniform approach would have been. 

 

 

Guests

Megan Messerly, health reporter, Nevada Independent; Brian Labus, assistant professor, UNLV School of Public Health; Marshall Allen, health reporter, ProPublica; Samuel Scarpino, assistant professor, Northeastern University’s Network Science Institute 

 

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