The proliferation of COVID-19 risk assessment tools in recent months is aimed at helping people make decisions about what to do and what not to do. How effective are these tools when they include what many experts call the most dangerous time of the infection so far?
Experts have warned against relying too heavily on any tool, but the urge to do so may be particularly strong as people re-evaluate even basic trips such as the grocery store. At the same time, during the December holidays and New Year’s Eve many people wish to have family and friends together, despite the ban on such gatherings at a California shelter.
So I decided to try some of the most popular risk assessment tools in San Francisco to see what they can say about my risk profile now and then get experts to weigh my findings. Big question: How will these tools affect or change my overall perception of risk?
Calculator UCSF in Pop Watcher used
Developed by a team of friends and housemates in San Francisco, the Microkowit Project Calculator creates a number of risk units measured in “microcovits” and allows users to get incredibly specific in simulating the risk of an encounter: you can see the danger in flying a N95 masked aircraft and flying in a N95 masked aircraft You can see the danger of kissing for minutes – indoors or outdoors.
A portion of the local population infected with the virus (which they calculate based on integrated data from Johns Hopkins, Govt Act Now, and Ever World in Data) also contributes to the spread of the tool.
Using this app, I can simulate meeting in a park with five friends in San Francisco – this is prohibited under the current lock order because the city only allows a maximum of one person living outside your own home. . I mention that we all wear surgical masks and engage in conversation and sit for at least two hours at intervals of at least 6 feet.
This function, according to the calculator, adds about 20 microcosms, where each microcosm is considered to have a 1 in 1 million chance of obtaining COVID-19. Moving a single crowd into the house – not allowed – raises my risk meter to the application’s red “highest risk” area and gives me a total of 500 microwaves.
The 1 million opportunity out of 500 is hard to process, but when I get into grocery shopping (assuming my normal 30 minute trip), I get a green “low risk” score of nine micro covids. When I calculate the risk of a two-hour indoor meeting with five people at Providence, RI, the vulnerability to the virus is much higher than it currently is in San Francisco, and I get 1,000 micro covids. Remove the masks from the picture and it jumps to 10,000.
“I think this is so much better than anything I’ve ever seen,” said Bob Watcher, head of the medical department at UCSF, who created an estimated risk of getting COVID using the app. When he chose to move to Florida to see his parents earlier this year, the latest uprising and the ban on essential travel, before the California lockout. At the time, the calculator gave him a 1 in 40 chance to get COVID.
“Even if not zero, it’s worth seeing all of me,” he said on Twitter in September.
Basic tool for assessing risk levels
The MyCOVIDRisk application, like the Microcovit calculator, asks for information about your location and the activity you are considering, and then spits out the risk score from “lowest” to “highest” based on the spread of your virus. Area.
“It can help by reporting smart closures and helping people choose safer things,” said Megan Ronnie, emergency physician and co-creator of the tool.
Now, the MyCOVIDRisk app tells me that meeting up to five friends (outdoors, for two hours, everyone wearing masks) is a “very low risk” activity. Moving the crowd into the house turns the score into a “high risk”.
Assuming there are five strangers wearing masks, what about going to the grocery store for 30 minutes? The app says this is a “medium risk”, between seeing friends outside with masks, seeing them indoors or having a 0.01% -0.1% chance of infection. The app offers ways to reduce my risk at the store: by wearing an N95 mask, staying 9 feet apart from others, or by wearing a face mask.
The application succeeds in making it clear that any indoor activity is socially more risky than remote outdoor activities, adopting a harm reduction-style approach that acknowledges the existence of certain functions that we inevitably have, but make them safer.
But the general risk estimates of the application (such as “low”, “low”, etc.) are not as effective as the size structure of the microcosm calculator.
Epidemiologist John Schwartzberg said, “Humans have a very difficult time, and I’m going to appreciate what the risk is, so I want people to have the tools.” But he does not know how many people will actually change their decision based on the results of any such tool. “They can’t address people’s own unconscious dependence on how they interpret danger,” he said.
Tools for assessing the risk of congestion
Japanese epidemiologist Yuki Froos’ calculator allows users to estimate the chance of having at least one infected person in a meeting, based on his research for a scientific study published in November. But it does not allow you to specify specific types of travel, such as meeting friends or shopping for groceries – and you must enter information about the overall population and number of new events on a daily basis.
In San Francisco (approximately 870,000 and 223 new cases per day), the probability of one person being infected at a party of five is 5.4%, assuming no one has symptoms. Increasing the number of people in the event to 10 increases the probability to 10.6%.
“The probability does not explain how much the spread is possible,” Furus said, adding that if people follow 3Ws such as washing their hands, wearing a mask and looking at their distance, the risk of infection can be reduced.
“I like to scare people, but they should not exaggerate,” Froos said.
Georgia Tech’s COVID-19 event risk assessment planning tool also assesses the likelihood of an intruder running into a crowd, depending on the size and location. Now for a 10 person event in San Francisco, that probability is about 11%, according to the map.
Increase the size of the crowd to 50 people and increase the chance to 43%. In Santa Clara County, the risk is 68%. In Providence, RI, it is 95%.
Like Fruise’s calculator, the map does not allow users to dive into different, specific types of crowds, but it can be useful to see how the extent of spread in your community affects your risk, or compare risk in one district with another.
Ellie Graydon, Associate Professor of Global Health Sciences and Safety at Georgetown University, said the Georgia Technology Map is a great way to demonstrate how the extent of spread in your community affects your risk.
“This is a very effective way to communicate, for example, with your mother-in-law, why you can’t thank each other together,” Graydon said.
I learned
The use of these risk tools, especially those that allow me to adjust variables to become as close as possible to the actual encounters I encounter, is a useful reminder of how a small factor can change the entire risk profile of a process.
A quick trip to the Safeway will turn into an hour’s drive. If you have to fly an airplane, there is a big difference between whether the seats in your rows are empty or full. The risk level of safe operation increases dramatically depending on the spread of the virus you have, which is constantly changing. All the small dangers of everyday life can be added.
But it’s hard to say that any tool has really helped me understand danger in a new way. Experts say we still do not know if they will have a significant impact on our actual safety.
George Rutherford, Professor of Epidemiology and Biology at UCSF, said: “There is nothing we can do to prevent the spread, and I will be there for all of these things, but sometimes we really need to find out if they work or not. “
Jenna Fowler is a San Francisco Chronicle staff writer. Email: [email protected]