NEW ORLEANS — An extensive study to test residents in New Orleans and Jefferson Parish and more accurately trace the infection rate of COVID-19 in the metro area found that at least 64,000 more people likely have had the coronavirus than previously thought.
Researchers with Ochsner Health released the findings of their COVID-19 prevalence study on Thursday, which found that nearly four times as many people in the parishes likely have been infected with the coronavirus disease than the 17,700 cases confirmed by the state health department. That projection is based on an infection rate of 7.8 percent of more than 2,600 people tested from May 11-15, the researchers said.
The results add to the experts' growing body of evidence that far more infected people are asymptomatic than previously thought. Of those who tested positive in the Ochsner study, 40 percent showed no symptoms.
Even more troubling was the fact that when carriers were at their most infectious – shortly after contracting the virus – 75 percent were asymptomatic or had yet to show symptoms.
“To me it was really alarming,” Ochsner research scientist Amy Feehan said. “And like I said before, we re-ran the numbers a couple of times and it was like, 'Could this really be real?' ”
Study organizers selected nearly 2,600 people out of a pool of 25,000 volunteers to be tested over a five-day period from May 11-15 in strategic locations around Jefferson and Orleans parishes.
The data showing a high potential of spread by asymptomatic carriers could result in a slower pace of re-opening, the researchers said.
“It definitely does throw cold water on the whole idea of re-opening. And it's frustrating. It's super frustrating, but that doesn't change the reality,” Feehan said. “Everyone's frustrated at this point. I'm frustrated. I don't want to live in COVID-land anymore. But the only way out of this is to start exercising safe behavior and reduce the spread and that's how we get back to some semblance of normal.”
Hospital staff performed both nasopharyngeal swabs (to test for active COVID-19 infection) and blood draws (to look for COVID-19 antibodies) to residents from representative neighborhoods, ages and ethnicities.
They found that 7.8% of people tested either were infected with COVID-19 or had been in the past, based off the presence of antibodies.
Three out of four people who had the disease or its antibodies were asymptomatic at the time of the test, while 40% said they had never experienced symptoms altogether.
Based off recorded COVID-19 deaths in the parishes, researchers also found that, so far, the coronavirus is 10-40 times deadly than the seasonal flu in the metro area. The death rate is 1.63%, while the flu is fatality rate is 0.04%-0.16%.
Three out of four people who had the disease or its antibodies were asymptomatic at the time of the test, while 40% said they had never experienced symptoms altogether.
Based off recorded COVID-19 deaths in the parishes, researchers also found that, so far, the coronavirus is 10-40 times deadly than the seasonal flu in the metro area. The death rate is 1.63%, while the flu is fatality rate is 0.04%-0.16%.
When factoring in the projected 64,000 unconfirmed cases, however, that COVID-19 fatality rate is significantly lower than based off of the state's cases alone.
The study found that Black people in the metro area have an infection rate nearly double that of white people -- 10.3% vs 5.9%.
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