Health

If the picture of COVID-19 in Colorado looks darker than it was in the early days of the outbreak, it's not your imagination, and it's not just happening here.

In previous peaks, COVID-19 data followed a relatively predictable pace: the percentage of positive test results increased, the number of cases increased, and then hospitalizations and deaths followed. Wastewater monitoring data wasn't widely available for much of 2020, but once online, it became an early warning sign if pollution started to rise.

Now these measures still exist, but they are less informative as fewer and fewer people are being tested. Some people have even started browsing online reviews of one-star scented candles - reduced sense of smell is a hallmark of COVID-19 - to get a general idea of ​​the area's trends, even if it doesn't help. To assess what is happening in a particular geographic area.

Positive rates and cases of COVID-19 have increased in Colorado since mid-October, but public health experts weren't sure the trend was real due to limited data. Uncertainty has largely eased this week, with hospitalizations rising sharply for the first time since June, albeit still relatively low compared to previous waves.

Being able to interpret early data is important because knowing what will happen allows hospitals to plan more patients and decide if people want to take extra precautions. Lorsque les hospitalizations ont commeinée à décoller dans le Colorado in anticipation of an uncertain viral delta in October 2021, the État avait environ deux semaines d'avertissement à partir des données de cas et de laaveréqueréant de laveriqueréant.

But now it's unclear what precautions might be needed if another wave develops in Colorado, Beth Carlton, assistant professor of environmental and occupational health at the Colorado School of Public Health, said last week that hospitalizations are limited. Data scientists need to know how to paint a clear picture so people know when they need to be more alert and when they can relax a little, he says.

"We really need to think strategically about key data," he said. "I think that's the most important question to ask right now."

Jude Payham, assistant professor at Colorado State University and the Colorado School of Public Health, said that wastewater monitoring does not differ from those who choose to get tested because anyone infected releases the virus in their stool. However, institutions collect their samples at different stages of the processing process, so some may be testing a larger population than others.

Another thing to consider, he says, is how to interpret the results in areas where the number of people using the facility fluctuates, such as in a mostly empty shopping area on weekends, or in a ski resort, the population. rising in winter.

"It's always hard to know the real side," he said.

Bayham and others have developed an algorithm to try to make sense of the noise. The filtered results are published on the Colorado Department of Public Health and Environment's Wastewater Dashboard, with virus levels in each category marked as rising, falling, or stable. The results are very useful in determining if there is an increase in infections in an area, he said, because people who are no longer infectious tend to shed virus particles in their stools for a while, which means that to reduce the more time incidence is required. Increase. .

Payham says that people who want to know the general course of infections can look at how the wastewater in their area has changed over time, but that won't tell you the exact number of infections on any given day.

"It's very useful, but it's still a high signal," he said.

Similar warnings apply to most types of data, said Dr. Ajay Seti, an infectious disease epidemiologist at the University of Wisconsin-Madison. He said the number of cases has long been underestimated, first because tests weren't available and now because so many people are being tested at home. Of course, some people don't feel bad and therefore don't know how to get tested.

The percentage of positive tests can also be skewed if relatively few people are tested. On Monday, 4,955 people were tested for the genetic material of the virus, which was reported in the state. As of October 31, 2020, more than 30,000 people have been tested, and as of the same date in 2021, more than 23,000 people have been tested. Most people don't report home tests to states, which means they can use the results to make individual decisions, leaving public health in the dark.

Those who don't want to be tested are more likely to be those who strongly suspect they have COVID-19, which could increase the positivity rate. However, Sethi said positive trends could give a rough idea of ​​what's going on.

"This week's data limit is no different from last week's limit or the previous two weeks' limit," he said.

Hospitalization is the most reliable measure, Sethi said, as medical facilities typically keep track of tests. Some people come to the hospital for a different reason and then test positive, he says, but it's always worth being aware of these cases because patients need to be separated from others and treated carefully.

Ultimately, however, it's best to pay attention to what local health departments are saying because it's part of the conversation about how the virus will affect the health system, Sethi said.

"The overall context is really important," he said.

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