As the third surge of coronavirus threatens most of the United States, public health experts across the country say there are still not enough tests available to maintain virus control.
Right now, some doctors and hospitals are offering a quick diagnosis to patients, which can provide results in minutes. And in the coming weeks, major pharmaceutical retailers like CVS and Walgreens will begin offering a type of rapid test called an antigen test, which is expected to give Americans more test access.
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“There is a need for testing across the board,”; Gigi Kwik Gronvall, senior scholar at the Johns Hopkins Center for Health Security, told NBC News.
Nearly 30 million Covid-19 tests are administered each month, according to estimates from The Atlantic magazine Covid Tracking Project. But studies have shown that the US will need millions more — 193 million a month, according to one report — to be effective.
A major issue is the lack of essential test supplies that have plagued labs ever since the pandemic began.
“The supply chain did not meet the demand,” said Drs. Patrick Godbey, president of the College of American Pathologists. “We still can’t get enough reagents to perform the tests we want to perform. It’s not just testing reagents, but supplies like wipes.”
In response, the federal government is pushing for rapid or point-of-care testing, as opposed to the gold standard polymerase chain reaction, or PCR test, which requires samples to be sent to a lab for testing and may take days. to return.
Two weeks ago, the Department of Health and Human Services began sending states rapid antigen tests performed by Abbott Labs. The test is the simplest to date as it does not require a machine and the results take about 15 minutes. Some state health officials told NBC News that the tests will be used in nursing homes and schools.
“Overall, I say this is a good start,” said Drs. Michael Mina, an epidemiologist at the Harvard TH Chan School of Public Health, on Friday in a press conference. “But I am very disappointed that the federal government is only continuing in this position where their only strategy is to buy what is available through industry and corporations in the private market.”
“Different areas require different types of tests,” Gronvall said. “The most important feature is the speed at which you can deliver accurate results.”
But accuracy is a thorn in the side of rapid testing, as witnessed this month by nearly 20 members of the Trump administration and campaign, including the president and first lady, infected with the virus. All White House staff and guests are said to be undergoing regular quick tests to screen for Covid-19.
The problem is that fast tests are not as sensitive as PCR tests, with up to 1 in 4 results being negative.
Approximately a dozen rapid tests have been authorized for emergency use of the Food and Drug Administration. All of these are intended for patients who experience symptoms, resulting when they have higher levels of the virus in their bodies.
“Point-of-care tests have a place and need to be defined by the individual situation,” Godbey said. “You are in the doctor’s office and you go in and have a fever, with symptoms that started five to seven days ago. The quick test has a place there. ”
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But the fear is that because these tests have become more widely available, they can be used as a screening tool, just as the White House does, a technique that backs up after guests at an event in Rose Garden last month said they do not have to wear masks after getting a negative quick test result. At least a dozen visitors ended up getting the virus.
“Negative results should not be viewed as a guarantee of negativity or safety,” Drs. Christopher Polage, director of the clinical microbiology laboratory at Duke University Health System.
A new study that looked at Abbott’s antigen test, called BinaxNow, found that it could work as a supplement to PCR testing. While the study was small and the results had not yet been published or peer reviewed, researchers at the University of California, San Francisco found that of the 26 people who tested positive for a PCR test, 15 of those it was also identified in Abbott’s trial. But researchers emphasize that those 15 are the most contagious because they also have a high amount of virus in their samples. Nearly half of those 15 are asymptomatic.
“Falling behind this pandemic could accelerate if we can deploy and act on a rapid test that finds people more contagious and in need of isolation, many of whom may be asymptomatic,” said May study author Dr. Diane Havlir in a news release “PCR remains the gold standard, but a strategic combination of these tests could help with public health settings where rapid results and risk knowledge delivery are critical to the day. trial. “
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Akshay Syal | contributed