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^ Honest question, so don't get upset with me. What is the difference between testing positive for virus infection and positive for having developed the antibodies? If they have the antibodies, then that is a very conclusive test that they have had the virus and had an infection. If you're a carrier of the antibodies but asymptomatic, then you are recovered, right?
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I’m interested in the air filtration thing. I figure most office buildings have shared air systems to some degree. Would a HEPA filter in your office, presuming you have an office instead of a cubicle, help if someone upstream in the HVAC system is coughing and sneezing SARS-COV-3?
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1989 3.2 Carrera coupe; 1988 Westy Vanagon, Zetec; 1986 E28 M30; 1994 W124; 2004 S211 What? Uh . . . “he” and “him”? |
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After a delay, your immune system starts recognizing the virus as something foreign and starts fighting it. As part of this process, you create antibodies to the virus. After you recover, the virus is no longer present in your body. You will test negative for the virus. You’re not infected anymore and not shedding virus thus not contagious. However, the antibodies will remain in your body, ”on guard” as it were. If a little bit of virus enters your body, your immune system will attack it right away, not giving it a chance to get established and start multiplying. You’re immune. And you’ll test positive for antibodies, which usually involves taking a blood sample. (Assuming you do actually become immune to this virus, which has been thought or hoped to be the case but is not really known). Yes, if you test positive for antibodies but negative for virus, then you are a recovered case. Being asymptomatic doesn’t mean much, it seems 50% or more of people who are infected are asymptomatic.
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1989 3.2 Carrera coupe; 1988 Westy Vanagon, Zetec; 1986 E28 M30; 1994 W124; 2004 S211 What? Uh . . . “he” and “him”? |
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^ Apologies in advance for going all Mahler on you guys.
But "test positive for the virus" how exactly? What are they detecting, if not the presence of antibodies? It's not like they smear blood plasma on a plate and hope to find .000000001 one actual tiny virus among all of the red blood cells. That would be ridiculously absurd. |
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Join Date: Nov 2002
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Si non potes inimicum tuum vincere, habeas eum amicum and ride a big blue trike. "'Bipartisan' usually means that a larger-than-usual deception is being carried out." Last edited by flatbutt; 04-26-2020 at 05:45 AM.. |
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Get off my lawn!
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Ah the ol' RTPCR test.
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Glen 49 Year member of the Porsche Club of America 1985 911 Carrera; 2017 Macan 1986 El Camino with Fuel Injected 350 Crate Engine My Motto: I will never be too old to have a happy childhood! |
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https://www.scientificamerican.com/article/heres-how-coronavirus-tests-work-and-who-offers-them/ The technology of virus testing is indeed pretty impressive. The sample is swabbed from where the virus is most found, in this case the respiratory system. Then - well, read https://www.emedicinehealth.com/pcr_polymerase_chain_reaction_test/article_em.htm#what_is_pcr_polymerase_chain_reacti on_used_for Something got a Nobel Prize for inventing this. For antibody testing, here is an article https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30788-1/fulltext Its maybe unappreciated that these tests are not simple, quick, or infallible. Often people think a task or service is easy and should be fast, cheap and perfect, while people actually doing the work are having to apply a bunch of judgment, steps, and technology to get something even sort of serviceable. We’ve had a bunch of discussion about antibody studies, for example, with people going ape over is it 1% or 4% of the population, but most engaging in the discussion don’t seem to realize how fallible the tests used in the study are. Common terms are sensitivity (what % of positive samples will be correctly reported as positive by the test) and specificity (what % of negative samples will be correctly reported as negative by the test). For antibody tests, a given manufacturer’s test might be (typical example) 95% sensitivity and 97% specificity. That means 1 - 95% = 5% false negative (test 1,000 persons with antibodies, test will incorrectly report 50 lack antibodies) and 1 - 97% = 3% false positive (test 1,000 persons without antibodies, test will incorrectly report 30 have antibodies). So, if you get “3% of population has antibodies!”, are you seeing the truth or false positives? I get them impression that the decision makers have a hard time getting their heads around this. https://www.cnn.com/2020/04/14/health/coronavirus-antibody-tests-scientists/index.html
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1989 3.2 Carrera coupe; 1988 Westy Vanagon, Zetec; 1986 E28 M30; 1994 W124; 2004 S211 What? Uh . . . “he” and “him”? |
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Join Date: Nov 2002
Location: NJ
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yep, we used it a lot back in the 80's at J&J.
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Si non potes inimicum tuum vincere, habeas eum amicum and ride a big blue trike. "'Bipartisan' usually means that a larger-than-usual deception is being carried out." |
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