Why are coronavirus tests so difficult to produce?



  • Testing for a replacement disease will always have teething problems. But when a worldwide pandemic means more tests got to be done faster than ever, how does one continue with the virus?
    W

    When it involves halting the Covid-19 crisis, virus testing is vital for diagnosing and for tracking the epidemic. It’s the sole thanks to uncover just what percentage people are infected, or could infect others.

    Despite how crucial testing is, some countries have much more tests than others – which testing isn’t available to everyone. the rationale comes right down to several factors, including timing, logistics, and therefore the complexity of collecting samples, obtaining the raw materials and equipment for testing, and having the expertise to try to to the tests accurately.

    The countries that acted swiftest in terms of testing have also been among the most important successes of the virus’s containment. Take South Korea , which began testing early in clinics, hospitals and drive-through centers. Its first confirmed case was on 20 January 2020. Six weeks later, on 16 March, South Korea was testing 2.13 people per 1,000. Italy, on the opposite hand, which had its first confirmed case on 31 January, was testing 1.65 people per 1,000 six weeks on. Even while Italy ramped up its numbers significantly – it’s now testing a far higher percentage of its population than South Korea , at 24.5 people per 1,000 compared to South Korea’s 11 – the slower start was one factor that made it harder to contain infections overall. (Figures range elsewhere: Spain is currently testing 20 people per 1,000, Australia 17, Canada 15, the US 12 and therefore the UK six.)

    You might also like:

    • are you able to catch Covid-19 twice?

    • The race to create coronavirus ventilators

    • what’s Covid-19’s real death rate?

    Starting testing later often meant the virus had chance to spread through whole communities by the time testing was implemented. Then came simple economics: as demand spiked, supplies were drained. The countries that reacted slowly required more tests to spot more infections as a result.

    A medical professional administers a Covid-19 test in Bolinas, California on 20 April 2020; the town is attempting to check each of its 1,600 residents (Credit: Getty Images)

    Testing alone doesn’t cause declines in disease. There are still questions on how reliable test results are for people that are asymptomatic, for instance . and therefore the biggest strides are seen in countries that combined testing with contact tracing and containment measures. Even so, testing allows public health authorities to collect data to form appropriate policy decisions – including about whether more selective or stricter social distancing policies are necessary.

    Why ramping up testing is so difficult

    Lagging countries are still trying to extend testing capacity. In early April 2020, for instance , the united kingdom Health Secretary announced an initiative to proportion to 100,000 tests each day by the top of April, a ten-fold leap from 10,000 each day at the top of March.

    But when it involves Covid-19 tests, scaling up by factors of 10 or 100 isn’t as simple as stocking up when emergency hits.

    That’s because the method of accurate Covid-19 testing requires coordination of variety of processes. First, you want to acquire the test kits – the long nasal swabs and chemicals required to process them. These are then sent to expertly-trained laboratory technicians who analyse the samples employing a PCR machine, which may be laborious. and eventually , there must be a system to simply accept samples and report results to the proper people.

    Laboratories that were previously doing research only (as against testing for patient care) not only need to run tests accurately – they even have to implement new computer and administrative systems to gather patient information then to distribute the results back to the health care providers.

    Making matters more complicated, many countries, including the united kingdom and therefore the US, have had problems getting enough supplies for testing. It’s not such a lot a matter of lacking the raw materials but ensuring they’re pure and mixed within the right amounts. Each brand of test has their own unique blend of about 20 chemicals. Each set requires its own unique packaging. Roche reagents don’t fit a Cepheid any better than a Chevy truck part fits a Prius. Making test kits is as burdensome as drug-making.

    Workers prepare components for testing kits in South Korea in March 2020; getting enough supplies for testing has been a challenge for several countries (Credit: Getty Images)

    In addition to chemicals, many laboratories lack the government-approved machines. within the US and South Korea , laboratories were allowed to file a so-called Emergency Use Authorisation application. This lets labs develop their own tests supported government protocols, but tweak them consistent with equipment.

    As a general rule, the better a test is to perform, the harder it’s to manufacture. the primary Covid-19 tests were simple to form but required specialised expertise. Many early tests take about four hours – two hours of hands-on work, two hours within the machines. Roche and Abbot instruments, available in some academic laboratories, can run 80 to 100 samples at a time. They’re partially automated but still require skilled technicians. Simpler tests that smaller hospital labs can run are hitting the market, but availability is sparse.

    Once a laboratory is about up and tests procured, the method can begin – starting with the pre-test.

    Pre-test procedure

    The pre-test begins with a nasal swab. this is often not a standard cotton ear-bud but an extended , skinny stick that’s flexible enough to increase to the ear. The swab is nylon or foam, not cotton, which inhibits the test.

    The nasal swab may be a long, skinny stick that extends to the ear (Credit: Getty Images)

    Even procuring those swabs has been difficult because of the crisis. Copan Diagnostics Inc, based in northern Italy, had to receive special government permission to continue production despite the Covid-19 lockdown. Puritan Medical Products, based in Maine, suffered labour shortages.

    As a result, nasal swabs are now precious. a couple of entrepreneurs try to form more with 3D printing, but there are teething problems, like any fresh technology. and therefore the vendors are charging 10 times or more what swabs wont to cost.

    Once the swab gets to the laboratory, a highly-skilled laboratory technician, wearing an equivalent protective clothing as nurses and doctors, places it into a biosafety hazard box – a glass box with controlled air flow to stop the virus from escaping.

    The process is dangerous. Laboratory work generates droplets. only one droplet may contain 1,000,000 approximately viruses which will contaminate the laboratory worker or the laboratory. It also can land in another sample. If that happened, a patient who didn’t have Covid-19 would be told they did.

    Laboratory directors love the cooking metaphor. Running a lab test, they say, requires a chef’s attention to detail, measuring precisely each ingredient at the proper time, within the right order and at the proper temperature. But unlike cooking – where a touch little bit of extra spice here or there may enhance the ultimate product, or at the worst case ruin the flavour – a faulty lab test can produce deadly results.

    A single droplet being tested can contain 1,000,000 viruses, making it crucial that medical professionals wear full protective gear (Credit: Getty Images)

    “One hiccup throws everything off,” said Dr. Kimberle Chapin, professor of pathology, laboratory medicine, and medicine, at the Warren Alpert School of drugs at Brown University and director of microbiology for the Lifespan Academic center , Rhode Island.

    Expert technicians with the meticulous skill to run the test are a scarce commodity in many countries.

    The testing phase

    The testing phase requires two crucial steps. First, extraction – retrieving the potential virus from the muck of the mucus on the swab, and second, detection.

    With garbed arms, technologists manipulate samples into tubes to be loaded onto an instrument where chemicals break open the viral coat (the “crown” of the coronavirus), and isolate the pure RNA, one strand of genetic material.

    Next, they pipette the RNA into a disc with tiny wells. Each has the reagent that hunts for particular pieces of the Covid-19 viral genome.

    The discs are taken to a machine where chemicals multiply short pieces of the viral genome a few billion times. These short pieces are then detected by a fluorescent probe that glows if Covid-19 is there.

    An employee holds up a Covid-19 testing kit in Chuncheon, South Korea (Credit: Getty Images)

    If the patient’s sample didn’t have the virus, then nothing happens. No multiplication. No glow.

    The technologist then checks the controls (the known positive and negative samples that prove the run worked), enters the results into the pc , and calls within the results.

    Ensuring accuracy

    The only thing worse than no test may be a test that’s wrong. Laboratories can only start testing patients after they need done sufficient studies to make sure reliability. These tests usually take upwards of six weeks, but technicians are working double shifts to hurry the method .

    To make matters more complicated, sometimes a patient can test negative even when they’re sick. they’ll have the virus in their lungs, but not release it near the nose where it might stick with the swab. Or, the sample wasn’t obtained correctly.

    Of course, this all describes swabbing as a way of checking out a live virus within the patient.

    But the newest buzz in testing is that the blood test: the antibody or serology test, which might be wont to establish if someone had the disease within the past and developed immune cells to get over it. It detects one specific a part of a patient’s immune reaction to the disease – the presence of antibodies. it’s hoped these proteins might protect patients from reinfection, although any protection remains to be seen.

    Devising an accurate antibody test ushers during a whole new set of challenges. It must make sure that it’s spotting the precise immune cells that fought this particular germ, and not some run-of-the-mill coronavirus, just like the cold . and a few people might get over the disease without ever developing antibodies.

    A specialist tests blood samples for Covid-19 in Hanoi, Vietnam (Credit: Getty Images)

    Even then, we don’t know enough about Covid-19 yet to understand if infected patients are not any longer susceptible. (Read more about whether you’ll get Covid-19 twice). Nor are there any proven, reliable antibody tests. the united kingdom bought many antibody tests that didn’t work.

    If we’ve learned anything thus far , it’s this: we will not ignore the warnings of communicable disease experts who, for many years , are calling for global preparedness for the inevitable new, dangerous viruses. One a part of this preparation includes a worldwide system to rapidly develop, prove, and distribute tests for a replacement virus as soon as possible after it strikes.

    Now quite ever, we believe the dedicated laboratory workers most folks will never see and yet are crucial members of the first-responder teams.

    Sheldon Campbell, MD, PhD may be a professor of laboratory medicine at Yale and associate chief for the clinical laboratories for the VA Connecticut Healthcare System. Randi Hutter Epstein, MD is that the writer in residence of Yale School of drugs and author of Aroused: The History of Hormones and the way They Control almost Everything.



Quiz 100% Result Quiz 100% Result
| |