Coronavirus Contextualized, 28th edition: Exploring, through data, COVID-19 in Nevada and beyond
Welcome to the 28th installment of “Coronavirus Contextualized,” a recurring feature in which we explore some of the numbers swirling around in the time of coronavirus.
Through these stories, we hope to parse the numbers, including confirmed cases of COVID-19, people tested, number of hospitalizations and deaths, and provide some context to them. You can view the prior editions of “Coronavirus Contextualized” here.
These accounts serve as a written roundup of the COVID-19 trends we kept our eyes on this week, with all graphs and charts living permanently on our COVID-19 data page, where they are updated multiple times a day with the latest numbers.
We’re continuing to take suggestions for what kind of data, graphs and trends you would like to see analyzed in future versions of this story or included in a future update of our data page. Reach out to [email protected] with any feedback.
Below, we take a look at some of the latest COVID-19 trends in Nevada as state and county officials attribute the rising number of COVID-19 cases statewide to an increasing number of people seeing coworkers, friends and family without masks or social distancing.
“We have an obligation to have an honest conversation with Nevadans about where we are and what will happen if we don’t take this seriously,” Gov. Steve Sisolak said at a press conference on Wednesday. “The public needs to understand that if we don’t step up together and follow all public health measures, hard decisions and trade-offs lie ahead.”
Cases and test positivity
Coronavirus cases continue to rise in Nevada.
As of Thursday, an average of 832 new COVID-19 cases were reported each day over the last seven days, up from 707 last week and 588 the week before that. At the recent low point on Sept. 14, an average of 267 cases were reported each day; at the peak this summer on July 20, an average of 1,176 new cases were reported each day.
The good news, however, is that cases are increasing at a slower rate than they were this summer.
“Although our numbers are going back up, they’re not growing at the rate they were previously,” Kyra Morgan, state biostatistician, said at a meeting of the COVID-19 Mitigation and Management Task Force on Thursday. “I would just add that that is one reason to support the idea of masks. It speaks to mitigation measures, because if we were seeing cases climb at the rate they climbed in June we would be in a pretty scary situation.”
There have now been 98,858 COVID-19 cases confirmed statewide since the beginning of the pandemic in March, with 5,827 new cases reported over the last seven days. That’s up from 4,946 new cases reported in the prior seven days and the 4,119 new cases reported in the seven days before that. At the peak in mid-July, 8,184 new cases were reported in a seven-day period, including 1,451 in a single day.
One in 31 Nevadans has tested positive for the virus since the beginning of the pandemic, or about 3 percent of the state’s population. Nevada ranks 17th in the nation for COVID-19 cases per capita, unchanged from last week.
Brian Labus, an assistant professor of public health at UNLV and former senior epidemiologist for the Southern Nevada Health District, attributes the increases to a number of factors, including what’s known as COVID fatigue.
“It’s not like there’s one item that is driving this outbreak,” Labus said. “Maybe there’s a little less concern about viral transmission. There is some fatigue, people are tired of dealing with this. We also have more opportunities to interact with others. Schools in some parts of the state have gone back.”
“Some people see that as a signal that we don’t have to follow the precautions anymore, when it’s more important than ever to follow those precautions,” Labus continued. “As behaviors change, the disease transmission is going to change.”
Part of the problem, he said, is that people take more precautions when case numbers are higher and fewer precautions when case numbers go down. That contributes to a ping-pong type effect.
“The problem is when those numbers go down, we can still get transmission,” Labus said. “It’s like trying to put out a fire. If you start to get it under control and you stop, it’s going to flare back up.”
Nevada’s test positivity rate — which looks at the percentage of tests or people coming back positive out of the total tested — has also continued to steadily increase. Again, we’ll look at two different methods of calculating test positivity below, using both individual people and a metric known as testing encounters.
Starting with the number of new reported people who tested positive for COVID-19 out of the total number of new reported people tested each day, the state’s seven-day average test positivity rate was about 20.4 percent as of Thursday, up from a recent low of 9.2 percent on Sept. 17.
The Nevada Independent is excluding Thursday’s daily test positivity rate from the seven-day average test positivity rate because the state reported an outlier of only 368 new people tested but 1,075 new people who tested positive. A spokeswoman for the Department of Health and Human Services, in an email, said the number was so low because some people had been previously tested on other dates.
This is one of the drawbacks to looking at test positivity using individual people, because some people are tested repeatedly. For instance, someone who tested negative four times but tested positive on their fifth time would be counted as a new positive person but not a new person tested. (In other words, they would be counted in the numerator but not the denominator.)
Additionally, someone may receive a rapid antigen test that comes back negative the same day, only to have a positive molecular PCR test, which is more accurate in determining whether someone is negative for COVID-19, come back positive several days later. In that instance, the individual would be counted as a new person tested the day of their first, negative test but a positive several days later.
Another way of looking at test positivity is to examine test encounters, or the number of individual people tested each day. This method of looking at test positivity excludes duplicate samples collected the same day but accounts for people who are tested repeatedly on different days.
It is not possible to independently calculate the test positivity rate based on test encounters because the state only reports the number of positive cases, not the number of positive test encounters . However, the state does provide this number, calculated as an average over a 14-day period with a seven-day lag. As of Wednesday, that number was 10 percent, up from a recent low of 6.5 percent on Sept. 19.
Whichever calculation you use to look at test positivity, the trend is the same: Test positivity continues to generally increase in Nevada and has been since the middle of September.
“People argue about what’s the best way: Per test, per people. Honestly, at a certain point it doesn’t matter, if it’s consistent,” Labus said, “as long as you have a comparison before and after, as long as you’re doing things consistently.”
A total of 798,618 people — or about one in four Nevadans — have been tested for COVID-19 and there have been 1,231,112 individual testing encounters since March.
COVID-19 deaths, however, have remained relatively low. As of Thursday, the average number of new deaths each day was 4.9, significantly down from a high of 20.7 on Aug. 20. The previous low point before cases started to increase this summer was 1.9 deaths per day, reported on June 28. State officials say that trends in deaths typically lag trends in cases by about five weeks.
Over the last seven days, 34 people have died of COVID-19 across the state, including 20 in Clark County, eight in Washoe County, three in Elko County, two in Lander County and one in Lyon County.
A total of 1,770 COVID-19 deaths have been reported statewide since March. Nevada ranks 22nd in the nation for deaths per capita, unchanged from last week.
COVID-19 hospitalizations have again generally started to increase.
There were 594 people hospitalized with confirmed or suspected COVID-19 on Wednesday, the last day for which data is available, up from a recent low of 417 on Sept. 12. At the peak over the summer, 1,165 people were hospitalized with COVID-19 on July 31.
“COVID is currently very manageable from the hospital and health care infrastructure standpoint, not taking up a whole lot of room in our hospitals at this point,” Christopher Lake, executive director of community resilience for the Nevada Hospital Association, said at the task force meeting. “But it is important to note that that is trending upward and we’re entering flu season where patients could, for lack of a better term, be competing with flu patients for hospital beds as well.”
As of Wednesday, 75 percent of licensed hospital beds and 60 percent of ICU beds statewide were occupied. Those numbers were 80 percent and 63 percent, respectively, in Clark County and 68 percent and 53 percent, respectively, in Washoe County.
County by county
Eight counties currently meet the state’s criteria to be flagged as at risk of elevated spread of COVID-19 as of Thursday.
Counties are considered at risk for elevated spread of COVID-19 if they meet two of the following three metrics:
- The average number of tests per day per 100,000, calculated over a 14-day period. If this number is less than 100, a county could be considered at risk.
- The case rate per 100,000, calculated by taking the number of cases diagnosed and reported over a 30-day period. If this number is greater than 200, a county could be considered at risk.
- The case rate per 100,000 and the test positivity rate, calculated over a 14-day period with a seven-day lag. If the case rate is greater than 50 and the test positivity rate is greater than 8.0 percent, a county could be considered at risk.
Washoe County continues to be the hardest hit by the virus, with a case rate of 689 cases per 100,000 people over the last 30 days, coupled with a 9.8 percent test positivity rate. Clark County, by comparison, has a case rate of 525 and a test positivity rate of 9.6 percent, while Carson City has a case rate of 624 and a test positivity rate of 8.2 percent. The other at-risk counties are Douglas, Elko, Lincoln, Lyon and Nye counties.
Counties, however, are only flagged as at risk by the state on Mondays, for purposes of determining whether the county needs to come before the COVID-19 Mitigation and Management Task Force. If a county makes the list two weeks in a row, they are required to present the task force with an action plan.
Washoe County, which has been on the state’s list for the last month, came before the task force on Thursday to present a mitigation plan that included limiting public gatherings to no more than 50 people, down from 250 people. Clark, Elko, Lincoln and Lyon counties remained on the list this week for a second week, while Carson City, Nye and Humboldt newly joined it.