US germ control laboratory creates test for pre-infectious Covid-19 carriers | News from the world



While pre-infectious detection would improve the effectiveness of testing and traceability programs as governments around the world ease blockages, Darpa warned that he must wait until FDA approval is granted and that the test can be put into practice to prove exactly how early it can get the virus.

“The goal of the research is to develop and validate an early host blood response diagnostic test for Covid,” said Professor Stuart Sealfon, who leads the research team at Mount Sinai Hospital in New York.

He said the test approach, which examines the body’s response to the fight against Covid-19, should produce results sooner than current tests on the nose that drive out the virus itself. “Because the immune response to infection develops immediately after infection, a Covid signature should provide a more sensitive diagnosis of Covid infection sooner,” he told The Guardian.

The research behind the test development will eventually be made public, with collaborating teams from Mount Sinai, Duke University and Princeton medical schools expected to publish online, allowing scientists around the world to try similar methods.

If the EUA is granted, the test is expected to start rolling out in the United States in the second half of May. Approval is not guaranteed, but Darpa scientists are enthusiastic about the potential impact as governments release blockages amid concerns over controlling potential second wave epidemics.


“We are all extremely excited. We want to deploy this test as quickly as possible, but at the same time share it with others who may want to implement it in their own country, “said Dr. Eric Van Gieson, who implemented the characterization program and Darpa epigenetic observation (Echo). last year to diagnose victims of biological warfare, and redirected it to focus on Covid-19. Epigenetics examines a set of controls on genes that can respond to the environment.

The hope that the test could detect carriers before they become infectious is based on previous research on other viruses, although Sealfon said it remains “unknown” for Covid-19.

“We have evidence that the diagnosis occurs within the first 24 hours for influenza and an adenovirus,” said Van Gieson. “We are still proving it with Covid-19. That said, we should know very soon after the EUA. He sees the potential for the United States to run up to a million tests a day, starting with 100,000 a day in May.

The test would increase the possibility of isolating pre-infectious cases and closing the chains of transmission. It could also significantly reduce quarantine periods for those exposed to Covid-19 spreaders, allowing them to return to work within a few days. “There could be exceptional demand,” said Chris Linthwaite, chief executive officer of Fluidigm, a California-based life sciences technology company that is part of the project, who believes that frequent testing can help manage the workforce. when they return to offices, warehouses and factories.

The British government announced two weeks ago that it would relaunch a contact tracing program that was abandoned at the start of the epidemic. Britain’s stated goal was 100,000 tests per day by the end of April. France announced Tuesday that it would test 700,000 people a week, including those without symptoms.

Other countries like South Korea, Australia and New Zealand already have effective tracking systems, but they would be strengthened if carriers could be detected early.

Coronavirus tests: how they work and what they show

Darpa experts also see the potential to improve protocols for protecting health and other workers in high-risk jobs, as well as those in relatively self-sufficient or isolated communities such as nursing homes and prisons or on board ships.

The test uses the same polymerase chain reaction (PCR) machines as those used to check the nasal swabs from people suspected of having the virus. “It’s a simple adjustment,” said Van Gieson. “The infrastructure is already there. “

The usage limitations are similar to those already faced by countries like Great Britain and depend on PCR capacity, stocks of chemical reagents and logistics. Results may take an hour or more if samples are to be sent to laboratories.

Like the viral test, the new blood test looks for a type of molecule called RNA. In this case, it is messenger RNA (mRNA). “Target mRNA is part of the immune response to viral infection,” said Sealfon. “The mRNA expression levels really adjust due to the presence of Covid-19. Understanding the immune response is essential to fighting Covid-19. “

Covid-19 is believed to incubate for approximately five days, at which point people are expected to become infectious. It is also at this point that the virus can be detected by current nose sampling tests. “They do the work, they just don’t tell you that someone is sick until maybe four days later [new test]Said Von Gieson.

Research shows accuracy levels above 95%. “This is something that will need to be constantly monitored as it will inevitably move up or down,” said Van Gieson.

Blood samples are more difficult to collect than nasal swabs, but can be more reliable. The swab test can be difficult because it requires taking a sample deep inside the nose.

“It can throw a lot of false negatives,” said Professor Lawrence Young of the University of Warwick, adding that recent studies showing low reliability were likely due to poor sampling of the swabs. “I was very concerned about the images broadcast on television about the driving tests. Something that you could reliably measure in the blood could be a good thing. “


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