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Disease X-19 News Review In Brief | On RSS Dog
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| Michael Novakhov – SharedNewsLinks: Google Alert – sars cov 2: Multiple Studies Raise Questions About Reliability of Clinical Laboratory COVID-19 Diagnostic Tests | ||
Mon, 29 Jun 2020 14:47:38 -0400
In the absence of a gold standard, researchers are finding a high frequency of false negatives among SARS–CoV–2 RT-PCR tests. Serology tests …
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| Michael Novakhov – SharedNewsLinks: Multiple Studies Raise Questions About Reliability of Clinical Laboratory COVID-19 Diagnostic Tests | ||
Mon, 29 Jun 2020 14:47:23 -0400
In the absence of a gold standard, researchers are finding a high frequency of false negatives among SARS-CoV-2 RT-PCR tests
Serology tests designed to detect antibodies to the SARS-CoV-2 coronavirus that causes the COVID-19 illness have been dogged by well-publicized questions about accuracy. However, researchers also are raising concerns about the accuracy of molecular diagnostics which claim to detect the actual presence of the coronavirus itself.
Diagnostic tests, typically involving a nasopharyngeal swab, can be inaccurate in two ways, said Steven Woloshin, MD, MS, in a news release announcing a new report that examines challenges and implications of false-negative COVID-19 tests. Woloshin is an internist, a professor at Dartmouth Institute, and co-director of the Geisel School of Medicine at Dartmouth.
A false-positive result mistakenly labels a person infected, with consequences including unnecessary quarantine and contact tracing, he stated in the news release. False-negative results are far more consequential, because infected persons who might be asymptomatic may not be isolated and can infect others.
Woloshin led a team of Dartmouth researchers who analyzed two studies from Wuhan, China, and a literature review by researchers in Europe and South America that indicated diagnostic tests for COVID-19 are frequently generating false negatives. The team published their results in the June 5 New England Journal of Medicine (NEJM).
For example, one research team in Wuhan collected samples from 213 hospitalized COVID-19 patients and found that an approved RT-PCR test produced false negatives in 11% of sputum samples, 27% of nasal samples, and 40% of throat samples. Their research was published on the medRxiv preprint server and has not been peer-reviewed.
The literature review Woloshins team studied was also published on medRxiv, titled, False-Negative Results of Initial Rt-PCR Assays for COVID-19: A Systematic Review. It indicated that the rate of false negatives could be as high as 29%. The authors of the review looked at five studies that had enrolled a total of 957 patients. The collected evidence has several limitations, including risk of bias issues, high heterogeneity, and concerns about its applicability, they wrote. Nonetheless, our findings reinforce the need for repeated testing in patients with suspicion of SARS-Cov-2 infection.
Another literature review, published in the Annals of Internal Medicine, titled, Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain ReactionBased SARS-CoV-2 Tests by Time Since Exposure, estimated the probability of false negatives in RT-PCR tests at varying intervals from the time of exposure and symptom onset. For example, the authors found that the median false-negative rate was 38% if a test was performed on the day of symptom onset, versus 20% three days after onset. Their analysis was based on seven studies, five of which were peer-reviewed, with a total of 1330 test samples.
Doctors also are seeing anecdotal evidence of false negatives. For example, clinicians at UC San Diego Health medical center treated a patient with obvious symptoms of COVID-19, but two tests performed on throat samples were negative. However, a third test, using a sample from a bronchial wash, identified the virus, reported Medscape.
The lesson for clinicians is that they cant rely solely on test results but must also consider their own observations of the patient, Joshua Metlay, MD, PhD, of Massachusetts General Hospital told Medscape.
Sensitivity and Specificity of COVID-19 Clinical Laboratory Tests
The key measures of test accuracy are sensitivity, which refers to the ability to detect the presence of the virus, and specificity, the ability to determine that the targeted pathogen is not present. So, a sensitive test is less likely to provide a false-negative result and a specific test is less likely to provide a false-positive result, wrote Kirsten Meek, PhD, medical writer and editor, in an article for ARUP Laboratories.
Analytic sensitivity and specificity represent the accuracy of a test under ideal conditions in which specimens have been collected from patients with either high viral loads or a complete absence of exposure, she wrote. However, sensitivity and specificity under real-world conditions, in which patients are more variable and specimen collection may not be ideal, can often be lower than reported numbers.
In a statement defending its ID Now molecular point-of-care test, which came under scrutiny during a study of COVID-19 molecular tests by NYU Langone Health, Northwell Health, and Cleveland Clinic, according to MedTech Dive, Abbott Laboratories blamed improper sample collection and handling for highly-publicized false negatives produced by its rapid test. An FDA issued alert about the test on May 14 noted that Abbott had agreed to conduct post-market studies to identify the cause of the false negatives and suggest remedial actions.
Issues with Emergency Use Authorizations
In their NEJM analysis, Woloshin et al point to issues with the FDAs process for issuing Emergency Use Authorizations (EUAs). For example, they noted variations in how manufacturers are conducting clinical evaluations to determine test performance. The FDA prefers the use of natural clinical specimens but has permitted the use of contrived specimens produced by adding viral RNA or inactivated virus to leftover clinical material, they wrote.
When evaluating clinical performance, manufacturers ordinarily conduct an index test of patients and compare the results with reference-standard test, according to the Dartmouth researchers. For people showing symptoms, the reference standard should be a clinical diagnosis performed by an independent adjudication panel. However, they wrote, it is unclear whether the sensitivity of any FDA-authorized commercial test has been assessed in this way. Additionally, a reference standard for determining sensitivity in asymptomatic people is an unsolved problem that needs urgent attention to increase confidence in test results for contact-tracing or screening purposes.
In a perspective for Mayo Clinic Proceedings, Colin P. West, MD, PhD; Victor M. Montori, MD, MSc; and Priya Sampathkumar, MD, offered four recommendations for addressing concerns about testing accuracy:
These protocols must evolve as diagnostic test, transmission, and outcome statistics become more available, they wrote.
Meanwhile, clinical laboratories remain somewhat on their own at selecting which COVID-19 molecular and serology tests they want to purchase and run in their labs. Complicating such decisions is the fact that many of the nations most reputable in vitro diagnostics manufacturers cannot produce enough of their COVID-19 tests to meet demand.
Consequently, when looking to purchase tests for SARS-CoV-2, smaller medical laboratory organizations find themselves evaluating COVID-19 kits developed by little-known or even brand-new companies.
Stephen Beale
Related Information:
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| mikenov on Twitter: Multiple Studies Raise Questions About Reliability of Clinical Laboratory COVID-19 Diagnostic Tests | Dark Daily darkdaily.com/multiple-studi | ||
| Mon, 29 Jun 2020 14:47:09 -0400
Multiple Studies Raise Questions About Reliability of Clinical Laboratory COVID-19 Diagnostic Tests | Dark Daily darkdaily.com/multiple-studi
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| mikenov on Twitter: Italy’s Cassandra: the scientist who challenged WHO guidelines – Reuters reuters.com/article/us-hea | ||
| Mon, 29 Jun 2020 14:40:38 -0400 | ||
| Saved Stories – Disease X-19: 12:11 PM 6/28/2020 | ||
Mon, 29 Jun 2020 14:15:41 -0400
 12:11 PM 6/28/2020 
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| Covid-19 Review: The Pandemic As The Bio-Info-Weapon: Saved Stories Disease X-19: 12:11 PM 6/28/2020 | ||
Mon, 29 Jun 2020 14:15:41 -0400
12:11 PM 6/28/2020
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| Saved Stories – Disease X-19: A new mutation makes it easier for the coronavirus to infect people | ||
Mon, 29 Jun 2020 14:15:26 -0400
As a public service, Shaw Media will provide open access to information related to the COVID-19 (Coronavirus) emergency. Sign up for the newsletter here
Know those little spikes on SARS-CoV-2 virus that bind it to a target cell and then infect it?
Well, those spikes have increased their functionality, thanks to a tiny genetic mutation, researchers recently learned through lab experiments.
This means more of the spikes on the variant that’s circulating throughout the U.S. and Europe are stable and able to latch onto cells, which makes it easier to infect people.
The study, The D614G mutation in the SARS-CoV-2 spike protein reduces S1 shedding and increases infectivity was published June 12 by Scripps Research.
Its authors, Hyeryun Choe, senior author of the study and Scripps Research virologist; and Michael Farzan, co-chairman of the Scripps Research department of immunology and microbiology, have studied coronaviruses for nearly 20 years, according to a Scripps Research news release.
The researchers dont know if the mutation will also increase the risk of severe illness or mortality, the news release said.
The study has not ye been peer reviewed.
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| Covid-19 Review: The Pandemic As The Bio-Info-Weapon: Saved Stories Disease X-19: A new mutation makes it easier for the coronavirus to infect people | ||
Mon, 29 Jun 2020 14:15:26 -0400
As a public service, Shaw Media will provide open access to information related to the COVID-19 (Coronavirus) emergency. Sign up for the newsletter here
Know those little spikes on SARS-CoV-2 virus that bind it to a target cell and then infect it?
Well, those spikes have increased their functionality, thanks to a tiny genetic mutation, researchers recently learned through lab experiments.
This means more of the spikes on the variant that’s circulating throughout the U.S. and Europe are stable and able to latch onto cells, which makes it easier to infect people.
The study, “The D614G mutation in the SARS-CoV-2 spike protein reduces S1 shedding and increases infectivity” was published June 12 by Scripps Research.
Its authors, Hyeryun Choe, senior author of the study and Scripps Research virologist; and Michael Farzan, co-chairman of the Scripps Research department of immunology and microbiology, have studied coronaviruses for nearly 20 years, according to a Scripps Research news release.
The researchers don’t know if the mutation will also increase the risk of severe illness or mortality, the news release said.
The study has not ye been peer reviewed.
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| Saved Stories – Disease X-19: Inside The US Government’s Top-Secret Bioweapons Lab – YouTube | ||
Mon, 29 Jun 2020 14:15:00 -0400
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| Saved Stories – Disease X-19: Inside the Georgian lab accused of testing biological weapons – YouTube | ||
Mon, 29 Jun 2020 14:14:49 -0400
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| Saved Stories – Disease X-19 – News Review: Inside the Georgian lab accused of testing biological weapons – YouTube | ||
Mon, 29 Jun 2020 14:14:49 -0400
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| Saved Stories – Disease X-19: gene editing – Google Search | ||
Mon, 29 Jun 2020 14:14:23 -0400
Genome editing (also called gene editing) is a group of technologies that give scientists the ability to change an organism’s DNA. These technologies allow genetic material to be added, removed, or altered at particular locations in the genome.6 days ago
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| Saved Stories – Disease X-19 – News Review: gene editing – Google Search | ||
Mon, 29 Jun 2020 14:14:23 -0400
Genome editing (also called gene editing) is a group of technologies that give scientists the ability to change an organism’s DNA. These technologies allow genetic material to be added, removed, or altered at particular locations in the genome.6 days ago
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| Saved Stories – Disease X-19: Germany Looks Past an Unpredictable U.S. in Setting EUs Future | ||
Mon, 29 Jun 2020 14:14:10 -0400
Sign up here for our daily coronavirus newsletter on what you need to know, and subscribe to our Covid-19 podcast for the latest news and analysis.
Gilead Sciences Inc. said it will charge the U.S. government and other developed countries $390 per vial for its coronavirus-fighting drug remdesivir, or about $2,340 for a typical five-day course of treatment.
Deaths from the virus surpassed 500,000 worldwide and confirmed cases exceeded 10 million as the World Health Organization reported the most infections for a single day. New clusters around the world indicate that the pandemic is far from over.
Tokyo reported more incidences of the disease, daily deaths in Iran reached a record and cases in Austria rose to the highest level since mid-May. Texas is fast becoming the new center of the pandemic in the U.S. while Vice President Mike Pence encouraged people to wear masks, two days after declining to give that specific guidance.
Key Developments:
Subscribe to a daily update on the virus from Bloombergs Prognosis team here. Click VRUS on the terminal for news and data on the coronavirus.
Gileads Remdesivir to Cost $2,340 for 5-Day Treatment (7:01 a.m. NY)
Gilead Sciences Inc. said it will charge developed nations $390 per vial for its coronavirus-fighting drug remdesivir, or about $2,340 for a typical five-day course of treatment.
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