Coronavirus general discussion and chit-chat

It’s not the same as being symptomatic, but they are either infected or have a false positive. Some percentage of people who have enough of an infection to be producing the virus, and this can spread it, and test positive for it, never develop symptoms, or at least, serious symptoms.

There’s no evidence that I’ve heard, though, of people having a latent infection for a long time, and then later becoming ill, as with HIV.

Sorry, color me dense, but people who are HIV-positive can transmit the disease (how is that latent?) even if they don’t have symptoms just like asymptomatic COVID -positive people can transmit the disease.

Can you restate as if to a 5-year old how being COVID -positive is different from or the same as being HIV-positive?

Latent as to their own illness.

This is all as far as I know as a lay person:
People who test positive for SARS-CoV-2, (the virus) may never become ill with Covid-19, but are expected to clear the infection and stop testing positive after a relatively short time, if they don’t become ill. They are people who have, essentially asymptomatic infection, which their bodies fight off, and then they are no longer infected, and can no longer spread the disease.

Others who test positive will have symptomatic Covid-19. There are multiple outcomes of that.

My understanding is, with HIV, once a person tests positive, without medication, it was extremely rare for a person to spontaneously clear HIV from their system – to recover from the infection. The person might remain healthy for a decade or more, but would continue to test positive the whole time. Eventually, they would become sick and die – uncontrolled HIV was almost always fatal. All of this is different now if the person has access to modern anti-HIV drugs, of course.

So, a person who tests positive for SARS-CoV-2 may or may not develop symptoms of Covid-19, but if they do it would be expected to happen in days. They may never develop symptoms, and clear the infection relatively quickly – asymptomatic infection. Whereas a person who tests positive for HIV would, untreated, be expected to continue testing positive for HIV indefinitely and would eventually become ill with AIDS. The latency period of the infection could last for a decade or more.

All-righty! Very clear. Thank you.

To my original question: testing positive for COVID isn’t the same as having COVID. And testing positive for HIV isn’t the same thing as having AIDS. But a COVID-positive person might “get over” it without ever actually having COVID and without treatment. Whereas an HIV-positive person will not get over it without treatment, and without treatment they will eventually have AIDS. Is that correct as you see it?

I think that’s right. Again, as I understand it as a lay person. Also, some of this is, I think, what the general assumptions are, but are actually unknown at this time.

For example, I think we know that people who tested positive who are never symptomatic will go back to testing negative. But it is unknown if they all do/will. It’s also unknown whether anyone could seem to have recovered, but then get ill years later. I think that is not expected, but it can’t be known at this point.

ETA: like the HIV/AIDS distinction, one technically tests positive for the presence of SARS-CoV-2, which is what causes the illness Covid-19. (Name of virus/name of illness)

Here is one huge distinction (that I got into a big argument about on another forum):

COVID-19 is a positive-sense single-strand RNA corona virus, which means it has some 70+ spikes that can latch onto a cell receptor; it injects its genetic material into a cell which is then used directly (positive-sense) to construct more virons which, when finished, bubble up out of the cell to look for other cells to infect.

HIV is a retrovirus, which means that its RNA load is transcribed to DNA to then be embedded into the cell nucleus, making the cell a permanent virus factory.

That’s pretty interesting. I’ve heard HIV referred to as a retrovirus but I never knew what that meant. I didn’t take biology in high school or college. I took nice clean physics (no bodily fluids, don’tcha know). Didn’t some AIDS scoffer back in the day claim that HIV couldn’t possibly cause AIDS because it was a retrovirus? I didn’t understand that argument then (or now), but that’s where I remember hearing the term.

Diseases (like COVID) can be asymptomatic, pre-symptomatic, or latent. Latent diseases can be infectious if there is a path from you to the other person, and not cause active disease in you if you are resistant and/or there is no path. I don’t know any good examples, but say you had a Staph skin infection, that infected a lot of other people: you still won’t get meningitis unless it gets into your cerebrospinal fluid: there is no easy path from your skin into your spine. There are lots of places in your body where diseases can hide, and can hide and be infectious even if you have a good immune response.

AIDS is an Auto Immune Disorder Syndrome. In normal speech, it is an Auto Immune Disorder Syndrome that is caused by HIV, in the same way that having a cough is caused by having a cold.

You can have a cold and not have a cough: you can have HIV and not have AIDS.

Normally, HIV doesn’t remain latent unless you treat it. Eventually it destroys so much of the immune system that you get AIDS. If you do treat it, you can prevent AIDS, but may still have enough of it that you can infect other people.

Well, the destroying of the immune system IS having AIDS. The only damage the virus does is to your immune system. Other ubiquitous germs that are normally held at bay by the immune system are what cause you actual problems (other than lacking an immune system).

Technically, you don’t test positive for the disease (COVID), you test positive for the virus SARS-CoV-2. The infectious disease (COVID) is the pathogenic state associated with the virus. A person with COVID can recover.

As for HIV and AIDS, @eschereal and @eschrodinger explained how it works very well. HIV is a retrovirus that infects T cells of the immune system and uses two enzymes to make its RNA genome into DNA and integrate that DNA into the host’s DNA. At this point, it is not very active at expressing the genes for making viral proteins. The viral load remains low and T cell stay at reasonable levels and the patient lives with chronic disease for sometimes decades. The viral load slowly increases and kills enough T cells for AIDS to develop. HAART (anti-HIV drugs) keep the viral load down.

Two patients have been cured by receiving bone marrow transplants from people who have a mutation (called delta 32) in the CCR receptor of T cells that HIV uses to enter cells. If HIV can no longer enter cells, no more HIV can be made. Viral load drops to zero. One of the guys died a few years later from leukemia but, not because he had HIV in his body anymore. Interestingly, they think this mutation evolved as a response to small pox.

I love this stuff (can you tell??)!

Yes! :slightly_smiling_face:

I’ve heard that Walmart was getting really crowded in some places. Starting today, Satuday, 11/14, Walmart will be limiting the amount of shoppers in their stores nationwide. Stores will only have 1 person per 1,000 ft of store space or 20% of capacity.

Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens for COVID-19

November 5, 2020. Recommends mid-turbinate or anterior nasal swabs as possible methods (that’s in the nose, or just back of the nose), not the deep swabs we were hearing about earlier.

“The following are acceptable specimens depending on the authorized SARS-CoV-2 viral test used:”

  • A nasopharyngeal (NP) specimen collected by trained healthcare personnel; or
  • An oropharyngeal (OP) specimen collected by trained healthcare personnel; or
  • A nasal mid-turbinate swab collected by trained healthcare personnel or by a supervised onsite self-collection (using a flocked tapered swab); or
  • An anterior nares (nasal swab) specimen collected by trained healthcare personnel, or self-collected and observed by healthcare personnel, or by home or onsite self-collection (using a flocked or spun polyester swab); or
  • Nasopharyngeal wash/aspirate or nasal wash/aspirate (NW) specimen collected by trained healthcare personnel; or
  • A saliva specimen collected by the person being tested, either at home or at a testing site under supervision.

A new(ish) buzzword in the UK is “lateral flow” test - with newsreaders and politicians blathering on about these things. Not actually saying what they are, or how they work (I’m guessing they don’t know) but nevertheless trying to sound authoritative. That sort of thing annoys the hell out of me - enough to
make me look up what these things actually are and how they work.

Anyways, as I’ve found out now, I thought I’d post this here as a kind of public service. It’s a handy little animation which explains it pretty well.

You’re probably going to have to stop and start the video, as it’s hard (for me at least) to watch the animation, read the captions and think all at the same time.

The one thing that isn’t well explained is the control line. As I understand it, one of the things that the conjugate pad is impregnated with is a specific ingredient (conjugate) which is detected at the control line (and not the test lines). If, for example, the sample is too small to flow through the device properly, it won’t flow to the control line to be detected. So if the control line isn’t activated, you know something went wrong with the test and you can’t rely on the result.

Hope this is useful.

j

A stick test. What have they said about the sensitivity?

Passengers on first flight from Melbourne to Sydney met by drag queens and Bondi life guards
This is actually a pretty significant route - in 2017, the Melbourne-Sydney route was the second busiest domestic route in the world. 9 million+ passengers, in a country with just about 22 million people. I suppose it helps that those two cities contain half the country’s population…
It’s good to see the border opened back up.

Interesting that you should ask. One reason that they’ve been in the news is because the UK government is rather gung-ho about them despite what experts say. For example, see this BMJ article from 17 Nov.

The government has claimed that rapid lateral flow covid-19 tests, which are being used in mass testing pilots in England and can provide results in 30 minutes, are “accurate and sensitive enough to be used in the community,” after evaluation results were published.
However, experts warn that the tests may miss as many as half of covid-19 cases, depending on who is using them—making them unsuitable for a “test and release” strategy to enable people to leave lockdown or to allow students to go home from university…

My post was not to praise them; rather it was to provide some information about what they are and how they operate, as (I’m guessing) we’re going to be hearing a lot more about them in the near future.

j

If that’s a representative example of what the experts say, then it looks like the government is right to be rather gung-ho.

Screening tests often give statistics like that, are often medically contentious for that reason, and are often useful in spite of the contention.

Like everybody else, many medical experts are uncomfortable with partial and incomplete information. As a group, politicians are more comfortable with partial and incomplete information, which they are forced to deal with and make decisions about as part of their job.

Most obviously, the observation that it will give a large number of false positives in a population with a low number of infections, just means that you will get better utilization of the slower and more definitive laboratory PCR tests. When you start throwing things like that out as an objection to self-testing, it means you’re being selectively quoted.

As I said, I was just passing on some information about what the technology is and how it works. But I’ll note this:

I think it’s the up-to-50% of false negatives that are the concern.

And this just in from the BBC:

Daily coronavirus tests will be offered to close contacts of people who have tested positive in England, as a way to reduce the current 14-day quarantine.
Prime Minister Boris Johnson said people will be offered tests every day for a week - and they will not need to isolate unless they test positive.

I’m wondering if the thinking is that testing someone seven times is one potential way (if an inelegant one) to address the false negatives. However, if I understand the BMJ article correctly, if the subject has a (consistently) low viral load, you might just get seven false negatives. At that point, call a statistician - I’m out.

j

…no the UK government is not right to be rather gung-ho here. They’ve been wrong about almost everything else, there is no reason to think that they’ve gotten it right here. It won’t allow " safe ‘test and release’ of people from lockdown and students from university" as the government claims. It isn’t about “being useful.” Its another attempt at a “quick fix” that ignores the overwhelming evidence that quick fixes like this don’t work.