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With Crispr, a Possible Quick Test for the Coronavirus – The New York Times, Nytimes.com

With Crispr, a Possible Quick Test for the Coronavirus – The New York Times, Nytimes.com

A pioneer of the gene-editing technology has devised a diagnostic test for the infection that could be as simple as a pregnancy test.

Scientists say it remains to be seen how the Crispr technique compares to the standard tests now in use, known as polymerase chain reaction, or PCR, shown here.

Credit …

Wladimir Bulgar / Science Source

(May 5, (Updated) : 37 pm ET

  • A team of scientists has developed an experimental prototype for a fairly quick, cheap test to diagnose the coronavirus that gives results as simply as a pregnancy test does.
    The test is based on a gene-editing technology known as Crispr, and the researchers estimated that the materials for each test would cost about $ 6.

    “We’re excited that this could be a solution that people won’t have to rely on a sophisticated and expensive laboratory to run, ”said Feng Zhang, a researcher at the Broad Institute in Cambridge, Mass., an d one of the pioneers of Crispr technology.

    On Tuesday, Dr. Zhang and his colleagues posted a description of their device on a website dedicated to their project, but their method has not yet been tested by other scientists, nor have their findings been published by a scientific journal that subjected them to scrutiny by independent experts.

    Two other teams of researchers, one in Buenos Aires and the other in San Francisco, are also working to devise new tests to detect the virus using gene-editing technology.

    Dr. Joshua Sharfstein, a professor of health policy at Johns Hopkins University Bloomberg School of Health, said that it was important that scientists search for new types of tests for the coronavirus. But he cautioned that the research so far offers only a proof of concept, and that it remains to be seen how well the test would perform in real-world conditions compared to the standard tests now in use, known as polymerase chain reaction, or PCR .
    “There’s a long way to go from that to a scalable technology that works,” he said. PCR is a venerable technology, invented years ago by the biologist Kary Mullis. It allowed scientists to find pieces of DNA that contained a particular sequence, even if that sequence was extremely rare.

    the researchers began by creating special tags that could grab onto the particular piece of genetic material they wanted to find. Once a piece was tagged, they could duplicate it. Repeating this procedure over and over again, PCR could create billions of new copies of the original piece.

    On its own, a single piece of DNA was too small to detect, but billions of copies were easy to spot . But if a sample did not contain the desired sequence, PCR would yield nothing.

    . Mullis won the Nobel Prize in for inventing PCR. It proved to be a workhorse for biological research, as well as for forensic DNA tests and other applications. In January, when scientists discovered the coronavirus that causes Covid – , they used its genetic sequence to create PCR tests for it.
    In a pandemic, however, PCR has some drawbacks. Its recipe involves many steps, which are typically carried out by trained technicians.

    Some companies have invented self-contained devices that test for the coronavirus and deliver a result in minutes. But the price tag for the devices can be steep, and the chemical supplies have sometimes been hard to come by.

    In order for states to safely reopen, public health experts say that millions of people will have to be tested every day. But the current state of testing is falling far short of that goal. Dr. Zhang and his colleagues hope to fill that gap with tests that were affordable and easy enough to use without special expertise.

    “You really need new technologies that are more distributed, that don’t require thousands of trained people or need centralized labs, ”said Omar Abudayyeh of MIT, one of Dr. Zhang’s collaborators.

    Dr. Abudayyeh, Dr. Zhang, and their colleague Jonathan Gootenberg at MIT’s McGovern Institute have been trying out Crispr to see if it can work as that new technology.

    Crispr originally came to fame several years ago as a way to precisely edit DNA. Like PCR, the procedure begins with the creation of a molecular tag that can lock onto a particular spot in a gene.

    The tag carries with it an enzyme. When the tag lands on the DNA, the enzyme cuts it at that spot. Crispr can be used to snip out a segment of DNA, or even replace it with a new piece.

    In recent years, scientists have figured out new things to do with Crispr’s tags and enzymes. Dr. Zhang and other researchers have been retooling it as a way to detect viruses.

    They fashion a tag that zeros in on a viral gene. But instead of cutting the gene, the enzyme gives off a signal that it has reached the target.

    In March, researchers at University of Buenos Aires in Argentina and at CASPR Biotech in San Francisco published the details of a Crispr-based test for the coronavirus. They posted a preprint online that has not yet gone through peer review. Last month, researchers at the University of California, San Francisco, and at Mammoth Biosciences published another Crispr-based test in the journal Nature Biotechnology .
    Dr. Zhang’s team has been working on a test of their own as well. They built it on research they published last year, before the pandemic. They created a Crispr-based system for detecting viruses they called Sherlock, short for (Specific High-sensitivity Enzymatic Reporter Unlocking

    Earlier this year, they adapted the Sherlock test to find the coronavirus. But their test, like those from other groups, required moving a sample into a series of tubes to carry out separate reactions.
    “It’s a little inconvenient, especially if you want to scale it up,” Dr. Zhang said. “So we focused our efforts on turning it into something that’s easy to run.”

    Recently, the researchers figured out how to combine a lot of the reactions in a single tube, allowing them to run the test faster and more cheaply. They called the method STOPCovid.

    For the reactions to finish, the tubes need to sit in water at degrees Fahrenheit for an hour. To see if the coronavirus is present, the researchers devised a procedure similar to a pregnancy test: They stuck a piece of paper in the tube. Two lines appearing on the paper meant the coronavirus was present.

    The researchers tried out the test on samples from patients with Covid – 26. For of them, they successfully detected the virus on 3 out of 3 tries. For the th, they succeeded 2 out of 3 times. When they tested five healthy people, all consistently tested negative. The researchers found that the test worked both on nasal swabs and saliva.

    The researchers estimate that the materials for one test would come to about $ 6. They are in discussions with manufacturers to create a single cartridge in which the two steps could take place. They expect that with mass production, the cost would go down even further.

    Dr. Zhang and his colleagues have set up a website with the instructions for STOPCovid in the hope that other researchers will try out their procedure and find ways to improve it.

      

        

                                                       Updated April ,

                                          
                     (What should I do if I feel sick?                 

    If you’ve been exposed to the coronavirus or think you have, and have a fever or symptoms like a cough or difficulty breathing, call a doctor. They should give you advice on whether you should be tested, how to get tested, and how to seek medical treatment without potentially infecting or exposing others.                                             (When will this end?)                  This is a difficult question, because a lot depends on (how well the virus is contained) . A better question might be: “How will we know when to reopen the country?” In an American Enterprise Institute report , Scott Gottlieb, Caitlin Rivers, Mark B. McClellan, Lauren Silvis and Crystal Watson staked out four goal posts for recovery : Hospitals in the state must be able to safely treat all patients requiring hospitalization, without resorting to crisis standards of care; the state needs to be able to at least test everyone who has symptoms; the state is able to conduct monitoring of confirmed cases and contacts; and there must be a sustained reduction in cases for at least days.                                             (How can I help?)                  The Times Neediest Cases Fund has started a special campaign to help those who have been affected, which accepts donations here . Charity Navigator , which evaluates charities using a numbers-based system, has a running list of nonprofits working in communities affected by the outbreak. You can give blood through the American Red Cross , and World Central Kitchen has stepped in to distribute meals in major cities. More than 45, (coronavirus-relatedGoFundMe fund-raisers have started in the past few weeks. (The sheer number of fund-raisers means more of them are likely to fail to meet their goal, though.)                                             (Should I wear a mask?)                  The C.D.C. has has recommended that all Americans wear cloth masks if they go out in public. This is a shift in federal guidance reflecting new concerns that the coronavirus is being spread by infected people who have no symptoms . Until now, the C.D.C., like the W.H.O., has advised that ordinary people don’t need to wear masks unless they are sick and coughing. Part of the reason was to preserve medical-grade masks for health care workers who desperately need them at a time when they are in continuously short supply. Masks don’t replace hand washing and social distancing.                                             (How do I get tested?)                  If you’re sick and you think you’ve been exposed to the new coronavirus, the CDC recommends that you call your healthcare provider and explain your symptoms and fears. They will decide if you need to be tested. Keep in mind that there’s a chance – because of a lack of testing kits or because you’re asymptomatic, for instance – you won’t be able to get tested.                                             (How does coronavirus spread?)                  It seems to spread very easily from person to person, especially in homes, hospitals and other confined spaces. The pathogen can be carried on tiny respiratory droplets that fall as they are coughed or sneezed out. It may also be transmitted when we touch a contaminated surface and then touch our face.                                             (Is there a vaccine yet?)                  No. Clinical trials are underway in the United States, China and Europe. But American officials and pharmaceutical executives have said that a vaccine remains at least to (months away.)                                             (What makes this outbreak so different?)                  Unlike the flu, there is no known treatment or vaccine, and little is known about this particular virus so far. It seems to be more lethal than the flu, but the numbers are still uncertain. And it hits the elderly and those with underlying conditions – not just those with respiratory diseases – particularly hard.                                             What if somebody in my family gets sick?                  If the family member does not need hospitalization and can be cared for at home, you should help him or her with basic needs and monitor the symptoms, while also keeping as much distance as possible,

    according to the guidelines issued by the CDC Carl Zimmer If there’s space, the sick family member should stay in a separate room and use a separate bathroom. If masks are available, both the sick person and the caregiver should wear them when the caregiver enters the room. Make sure not to share any dishes or other household items and to regularly clean surfaces like counters, doorknobs, toilets and tables. Don’t forget to wash your hands frequently.                                             (Should I stock up on groceries?)                  Plan two weeks of meals if possible. But people should not hoard food or supplies. Despite the empty shelves, the supply chain remains strong. Carl Zimmer And remember to wipe the handle of the grocery cart with a disinfecting wipe and wash your hands as soon as you get home.                                             (Can I go to the park?)                 

    Yes, but make sure you keep six feet of distance between you and people who don’t live in your home . Even if you just hang out in a park, rather than go for a jog or a walk, getting some fresh air, and hopefully sunshine, is a good idea.

                                                Should I pull my money from the markets?                  This is not a good idea. Even if you’re retired, having a balanced portfolio of stocks and bonds so That your money keeps up with inflation, or even grows, makes sense. But retirees may want to think about having enough cash set aside for a year’s worth of living expenses and big payments needed over the next five years.                                             (What should I do with my) (k)?                  Watching your balance go up and down can be scary. You may be wondering if you should decrease your contributions – don’t! If your employer matches any part of your contributions, make sure you’re at least saving as much as you can to get that “free money.”                                                             

     
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