The concept behind a home kit is simple and is similar to how doctors quickly detect strep throat and flu: A paper strip could swab a saliva as a nasal sample and return a positive or negative result within 15 minutes. Otherwise, their children could swap and find out if they were contagious before deciding if they should be sent to school. Students, colleagues, and anyone who would go to a restaurant or an event would also benefit from such tests.
“These have so much promise because they can help completely crush the infections,” said Dr. Michael Mina, an assistant professor of epidemiology at the Harvard TH Chan School of Public Health. “If we can all get the number of our cases very low, everyone is safer.”
But without these new options, Mina and other scientists said, the country will continue to be hoarded by the current system that requires tests sent to a lab for processing. Critics say the system was never designed to handle the massive load of coronavirus tests, which has led to delays of more than a week in getting results.
Mina joined various public health experts by promoting screening at home, known as antigen testing, on social media, and chiding regulators for their new rules.
On Friday, a frustrated Mina revealed that he had talked to companies about the possibility of no longer waiting for FDA approval and “just producing hundreds of thousands or millions” of these tests, with the caveat that they are only used for large-scale studies.
“I’m talking to governors and senators and members of Congress, and they’re writing letters to the FDA, so this is moving,” Mina said. “There’s a lot of pressure right now from all walks of life, trying to get these things right and the FDA crawling on it.”
But the FDA has so far been clear of the debate.
The system in widespread use now, known as molecular testing, requires a multistep laboratory process to extract genetic material from a nasal or saliva sample, amplify it and look for signs of the coronavirus. In contrast, rapid antigen tests simply detect specific proteins on the surface of the virus, a process that does not require time-consuming laboratory equipment. But they can miss infections and produce more false negative findings, especially among people who do not have heavy loads of the virus.
Furthermore, scientists find that people with COVID-19 are generally most infected the first week or so after being exposed to coronavirus and often before they have symptoms. But patients often see waiting times to test, and although molecular tests can still detect traces of virus and return a positive finding, the result may well pass the time many people are infected.
To protect against false negative results with rapid antigen testing, and to catch people when they are most infected, consumers would be expected to test themselves frequently, perhaps several times a week, say Mina and other scientists. The cost of each test is expected to be a few dollars, as opposed to the $ 100-plus pocket fee that is often charged for uninsured molecular tests.
“I oppose the coffee model against the espresso machine model,” Mina said.
An FDA spokeswoman declined to comment on the debate over rapid anti-testing at home at COVID-19, instead noting the agency’s statement when it issued new guidelines on July 29. The guidelines require anti-counter-testing for COVID-19 to have the ability, known as test sensitivity, to detect at least 90 percent of the cases. That is 20 to 30 percentage points more sensitive than most COVID-19 rapid home tests currently in development. In contrast, the FDA requires COVID-19 tests processed in labs to detect at least 95 percent of cases.
“While the recommended sensitivity for these non-lab tests is lower than on lab-based tests, the tremendous benefits of wider access to simple and rapid test options are generally greater than this risk,” the FDA said in its July statement. .
The Rockefeller Foundation, a nonprofit focused on health, energy, and social justice issues, recently called on the federal government to work more closely with businesses and scientists to develop affordable rapid coronavirus anti-testing. It has allocated $ 100 million to a COVID-19 test and contact tracking initiative.
“We need a paradigm shift from beautifully accurate but slow tests, to fast and good enough to make quarantine,” said Mara G. Aspinall, a professor at State University, and co-author of the coronavirus plan. foundation, in a statement. “Slowly and accurately works for clinical management, but this virus is a sprinter not a marathon runner. We need to fast and often test just to keep up. ”
But other health professionals say there are too many details yet to be worked out to open the gates in do-it-yourself COVID-19 testing. Dr Kimberle Chapin, a professor of pathology and laboratory medicine at the Warren Alpert School of Medicine at Brown University, said she was concerned that the cough tests were not affordable for everyone. And, she said, it is not clear how home screening test results would be reported to doctors and local and state nurses.
She said doctors need to be on hand to explain to consumers about quarantine, while health officials need to know when and where people test positive to catch clusters and outbreaks before they spread.
“Increasing the availability of COVID testing and testing options should be done within a larger public health strategy that includes follow-up care, contact tracking, and data reporting,” said Chapin, who is also director of microbiology at Lifespan Academic Medical Center in Rhode Iceland.
Karla Satchell, professor of microbiology-immunology at Northwestern University Feinberg School of Medicine, said antigen testing will play a pivotal role, but should be more accurate than most currently in development.
“Even at 90 percent [sensitivity] “That means 10 percent of the positive people walk through your front door to work and that could be quite a number of people,” Satchell said. “We need to maintain high standards for what we bring to market.”
One company that says it has a rapid antigen test to go is E25Bio, a Cambridge startup spun from a lab at the Massachusetts Institute of Technology. Irene Bosch, co-founder of the company, said that E25Bio developed the test in March, but could not convince local hospitals to validate it by testing several hundred patients and comparing the results to those of molecular tests. The company finally got the go-ahead from a hospital in Florida this summer, she said.
The test, Bosch said, can detect about 70 percent of cases among patients with high-grade coronavirus, and becomes less sensitive with declining viral levels. E25Bio has submitted an application to the FDA, but is not optimistic, given the agency’s guidelines for a 90 percent threshold.
“What would change the FDA’s mindset?” Frege Bosch frustrated.
Other countries, including Belgium, have approved rapid antigen testing for COVID-19, with sensitivity levels lower than 60 percent, Bosch said.
‘It is better to see with one eye,’ she said, ‘than to be blind.’
Kay Lazar can be reached at [email protected] Follow her on Twitter @GlobeKayLazar.
