Missouri will add antigen tests to its COVID report, increasing positive case counts

Friday morning update will be first look at county-level and statewide data on ‘probable’ cases

By: - March 4, 2021 8:42 pm

The deaths data, which the department calls “probable” COVID-19 fatalities, is being added eight months after the department began reporting antigen-identified infections in its daily report (image courtesy of CDC).

Data on COVID-19 infections that local health departments have been reporting for months – and telling their communities represent the most accurate picture of the virus’ spread – will be added to the state health reports starting Friday

The change is expected to add tens of thousands of cases to the state’s report that on Thursday showed 479,536 people have had the illness caused by the coronavirus since the first case in early March 2020.

The data, reporting positive results from rapid antigen cases, will be the first statewide look at the total number and distribution of cases local health agencies have been reporting as “probable” infections.

“That’s the plan at this point, assuming all goes well in the morning when our data analyst flips the switch,” Lisa Cox, spokeswoman for the Department of Health and Senior Services wrote in an email Thursday night. “It will include county-level testing, case and positivity rate data.”

The state’s COVID-19 dashboard until now has only gave that detail for cases confirmed by the more accurate PCR test. The state’s 111 local health departments that post COVID-19 information online had almost 55,000 more cases as of Tuesday than the state health agency has reported for those same counties, according to a review of the data by The Missouri Independent.

While the state reported 470,530 cases for those counties, the local health agency reports checked Tuesday showed a total of 524,350 cases, with the main difference coming from positive antigen tests not included in the state total. 

In some counties, the local count was more than double the state count of confirmed cases.

In interviews this week, local public health officials have said the difference between their reports and the state report has created confusion, and at times anger, in their communities.

“We have been looking into this for several months because we keep getting that question,” said Debra Bradley, administrator of the St. Joseph Health Department.

On the state dashboard, Buchanan County was listed Thursday as having 6,966 cases, while Bradley’s department reported 10,095, with 2,982 listed as “probable.”

Some public health leaders got a preview of the updated report Thursday during a Zoom meeting with the state Department of Health and Senior Services, said Larry Jones, executive director of the Missouri Center for Public Health Excellence.

“I can tell you that antigen testing has become more and more the preferred testing because of the speed,” Jones said. “More laboratories are running it than run the PCR test.”

There will be another meeting Friday afternoon for feedback after agencies have had a chance to see the data presentation, Jones said.

“They want to visit with us about the report and get some feedback and find out what else is needed,” he said.

The PCR test was the earliest test for COVID-19 and is the best known. It is the one that requires a long swab to be inserted into each side of a person’s nasal passage to take a sample. Obtaining results can take many hours, sometimes days.

The antigen test also confirms that a person is currently infected with COVID-19 and infectious, but it has a higher rate of false negative tests. The results can be obtained in as little as 15 minutes.

“We love those tests,” said Lori Moots-Clair, administrator of the Knox County Health Department and Home Health Agency. “They have been extremely helpful, especially with our school students or faculty.”

In recent weeks, as much as 45 percent of all coronavirus tests in Missouri have been antigen tests. The use has increased as the daily tally of PCR-confirmed cases has been falling steadily.

The third type of COVID-19 test is known as an antibody test, and shows that someone has been infected sometime in the past, not that they are currently ill or contagious.

Local health departments have handled antigen-test positive cases the same way they have handled PCR-confirmed cases, with isolation, contact tracing and quarantine for close contacts.

“Our local hospital had issues with securing PCR testing,” said Linn County Health Administrator Krista Neblock. “They were not able to get enough to meet the demand and had to move to the antigen testing.”

The department has been presenting some antigen test data for several weeks. The state’s “COVID-19 in Missouri at a Glance” page gives the total number of positive PCR and antigen tests over seven days, updated daily. On Thursday, it showed 1,630 antigen cases in the week ending Monday, an average of 233 per day, and 2,310 PCR-confirmed cases, an average of 330 per day.

And the page under the testing tab shows that there have been 878,145 antigen tests administered to 359,455 people with 82,909 positive results. By comparison, there have been 4.5 million PCR tests administered to 2.3 million people with 529,491 positive results.

The page where statewide situation is summarized, data updated Thursday morning showed that 479,536 people have had confirmed cases of COVID-19, meaning about 50,000 of the positive PCR tests have been duplicates.

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Rudi Keller
Rudi Keller

Rudi Keller covers the state budget, energy and the legislature. He’s spent 22 of his 30 years in journalism covering Missouri government and politics, most recently as the news editor of the Columbia Daily Tribune. Keller has won awards for spot news and investigative reporting.