White House report says Louisiana is in the red zone for COVID-19 cases; rapid testing gets more attention

White House report says Louisiana is in the red zone for COVID-19 cases; rapid testing gets more attention
A nurse takes a swab from a patient during a COVID-19 mass testing event. (Source: Gage Cureton)

NEW ORLEANS (WVUE) - A report from the White House Coronavirus Task Force says Jefferson, Orleans, and St. Tammany parishes are among the top ten parishes in Louisiana based on the number of new COVID-19 cases in the last three weeks. Caddo, East Baton Rouge, and Ouachita are at the top of the list.

The White House says Louisiana is experiencing a resurgence in COVID-19, with rising test positivity, cases of the virus, and hospitalizations. Furthermore, it says Louisiana is in the red zone for cases, indicating 101 or more new cases per 100,000 people, and the state has the 38th highest rate in the country.

The report comes as the state health department says rapid COVID-19 test results are now more on its radar. Antigen tests now appear on the Louisiana Department of Health’s (LDH) online dashboard and are incorporated into the state’s COVID-19 data and calculations.

Dr. Joe Kanter is interim assistant secretary of the Office of Public Health within LDH.

“You’ll see those numbers broken out, subdivided into confirmatory or PCR, or probable/antigen,” Dr. Kanter said.

PCR is an often-used molecular test. Antigen tests detect certain proteins in the virus and produce faster results.

“We need to make sure that we have good visibility across the board. We want as much signal coming in on what this outbreak is doing and increasingly, the antigen tests are becoming an important part of that,” Dr. Kanter said.

LDH tweeted Thursday, Nov. 19 that, “Since yesterday, 27,961 new tests have been reported to the state, bringing the total number of tests to 3,184,631. Of the tests reported today, 25,487 were PCR tests and 2,474 were antigen tests.”

“The antigen test is generally considered to be faster, but perhaps not quite as accurate as those nucleic acid tests,” said Dr. Bob Garry, a Tulane University virologist.

He says the antigen test also engages the nose.

“Generally, you still have to do the nasal swab,” Dr. Garry said.

Dr. Kanter says in other ways, antigen tests differ from PCR tests.

“The pros: that it is typically less expensive than what we consider the formal or gold standard testing, which is a PCR. It’s quicker, typically it takes 15 or 20 minutes to do, and in most cases, it can be done at the bedside or point-of-care right next to a patient. It doesn’t need to be sent off to a lab. Those are all the pros. The cons are that in most cases, it’s not as sensitive,” Dr. Kanter said.

Still, a positive result is viewed as being accurate.

“For anyone that receives a positive antigen test, in all likelihood, they have COVID and they need to be acting as if it was a positive PCR test without question about that,” Dr. Kanter said.

But are negative results truly negative?

“There’s some little wiggle room in there and that comes into the question of the accuracy. The antigen tests tend to miss a few of the positives,” Dr. Garry said.

Timing is everything when taking either test. Dr. Garry says it’s best to wait several days after being exposed to someone who has or is suspected of having the virus.

“You need to wait for several days and most people now recommend four or five days because that’s how long the latency period of the virus, that’s how long it takes to grow up in your body, get into your nose, so that you actually do an accurate test,” Dr. Garry said.

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