Cases, Deaths, Hospitalizations: How to Make Sense of COVID-19 Stats

  • Inconsistent messaging and misinformation can make important statistics about the COVID-19 pandemic confusing and difficult to understand.
  • Experts say one of the most useful numbers to determine the risk in your area is the percentage of tests that come back positive, or simply the percent positive.
  • Another important number to experts is the percentage of occupied beds in an intensive care unit (ICU) occupied by COVID-19 patients.
  • This number shows the trajectory of the infection and an area’s ability to cope with a surge in cases.

During a speech from the White House Tuesday, President Donald Trump said increasing testing that showed more COVID-19 cases was “fodder for the fake news to report cases.”

“If we didn’t do testing, instead of testing over 40 million people, if we did half the testing we’d have half the cases,” Trump said. “If we did another, you cut that in half, you’d have yet again half of that.”

With that kind of dizzying logic, Trump argues that fewer tests would mean fewer positive results — which is technically true — but experts say that more tests wouldn’t necessarily reveal more cases, if the infection rates were coming under control.

So, what numbers — total cases, total deaths, percent positive, etc. — are the most meaningful when people are looking for reliable information regarding the status of the pandemic?

“What we’re all doing is watching the news and wondering how bad it is in the areas where we live,” said Dr. Miriam Isola, DrPH, a clinical assistant professor of biomedical and health information sciences at the University of Illinois, Chicago. “When people look at all these numbers, they wonder what it will mean for themselves and their family.”

That includes whether it’s safe to return to work or school, should local authorities determine they’re allowed to reopen.

Percent positive and 7-day averages

One of the most useful numbers to determine isn’t the sheer number of cases, but rather the percentage of tests that come back positive, or simply the percent positive.

According to Johns Hopkins University, positive COVID-19 tests in the United States surged to nearly 22 percent at the end of March when testing wasn’t as widely available and was being reserved for hospitalized patients.

Those numbers dipped to around 4 percent in June as more people were being tested — such as essential workers with asymptomatic infections — but as of Wednesday had a 7-day average of 8.7 percent.

Dr. Amesh Adalja, an infectious disease expert and senior scholar at Johns Hopkins Bloomberg School of Public Health in Maryland, says, for example, if testing in an area shows 10 percent of people have the virus, then the infection is now “out of control.”

“If that’s increasing, the spread is surpassing public health efforts to suppress it,” Adalja told Healthline. “It shouldn’t be easier to find cases.”

But that doesn’t mean more testing will ultimately show more cases. It will, however, show the full extent of an outbreak in any given area.

Here’s another example: If you do 20,000 tests and 3 percent come back positive, doing the same amount of tests or more should show the same rate. If it shows more, the outbreak is worsening.

While the president has urged experts to slow down testing, infectious disease experts say it’s important to do more testing to find those cases so people can isolate and not infect others.

While not all may require hospitalization, people with mild cases are still a threat to others who may not fare so well.

“We’re trying to catch them because they can still transmit,” Adalja said.

Dr. Gregg Miller, a practicing emergency department physician and chief medical officer at Vituity, says 7-day averages are more reliable than daily numbers.

That’s because daily counts are down on the weekend when fewer tests are being conducted, and fewer administrative personnel are working and reporting case counts.

One recent example is July 10, when data from the Centers for Disease Control and Prevention (CDC) shows the United States had its largest 1-day spike so far at more than 66,000 new cases of COVID-19, but a 7-day average of under 55,000 cases.

“While case counts are an important number to track, they can be influenced by the number of tests that are being done. Previously there were a lot of COVID-19 cases that we couldn’t diagnose because we didn’t have the capacity to test,” Miller said. “So, if you just look at an increasing number of cases, you don’t know if that’s due to disease spreading or more testing.”

That’s why he says the percentage of positive cases is so important.

“When that number increases — which is happening right now in many states — then that means cases are truly going up,” Miller said.

“It is absolutely clear that the increase of cases in the USA right now is due to a true increase in the pandemic, and not just due to more testing,” he added.

ICU numbers

Another important number to experts is the percentage of occupied beds in an intensive care unit (ICU) occupied by COVID-19 patients, because that shows the trajectory of the infection and an area’s ability to cope with a surge in cases.

According to CDC data, from June 27 to July 10 — the last 2-week period for which data is available — states like Maryland, Rhode Island, and Utah are seeing COVID-19 patients in their ICUs decreasing at rates around 3 to 4 percent.

But other states — like Idaho, Florida, and North Dakota — are seeing their ICUs increase with COVID-19 patients in ranges from 3 to 5 percent.

Those numbers can be troubling. Without ICU space or available ventilators, some people who need emergency care won’t be able to get it.

It’s also an important number because of the costs associated with being hospitalized with COVID-19.

A study published in Health Affairs in April suggested the median costs of a hospital stay for COVID-19 patients would cost more than $14,000. That doesn’t consider any follow-up care.

Then again, one Seattle man’s hospitalization, including 4 weeks on a ventilator, left him with a $1.1 million hospital bill.

“This is a natural experiment to see what happens when we don’t have nationalized healthcare,” Isola said.

Number of deaths

On Friday, the CDC recorded more than 70,000 newly confirmed COVID-19 cases and a total of more than 137,000 deaths since the pandemic began.

That, Isola says, means that the United States has seen the death rate of two flu seasons in only 4 months.

“As an epidemic, yes, this is worse than the flu,” she said.

But even the numbers regarding deaths aren’t as clear-cut as experts would like, as the immediate cause of death isn’t always the underlying cause of death.

For example, Miller says if someone dies due to a car crash from drunk driving, the immediate cause of death is the trauma and motor vehicle accident, but the underlying cause of death is drunk driving.

“If someone died because they caught COVID-19, which triggered a heart attack, which was due to their high blood pressure, which was due to living in a stressful neighborhood with violent crime and no easy access to healthy food — what was their cause of death? Was it the virus, was it a heart attack, was it high blood pressure, was it a social determinant of health?” he said. “Really, it was all of the above, but it’s hard to cram it all onto a death certificate.”

Miller says regardless of minor data nuances, it’s clear that too many Americans have died of a preventable disease.

“We can and should take actions to prevent future deaths,” he said.


Source: Read Full Article