Absolutely. These are human beings. They are flawed. They are often selfish and short sighted. And even at their best, they have lives to get back to. Adding three weeks of detention is going to hold back much-needed staff. I am in the demographic that would go, and I could spend three weeks away from my one year old, but not six weeks.
Holding people in detention in an untrustworthy country with no assurance they will receive modern treatment and be able to see their families if needed will destroy the response.
Iggy, what, if any, are the risks to the health care workers collecting tissue biopsies vs. a blood draw? I’ve never done it, so I don’t know. Is it more or less (or about the same) likely that a lymph or spleen biopsy procedure will expose workers to the virus?
Just wondering if the test procedure itself may carry more risks, not just to the patient, but also the staff. A blood draw is a very low risk procedure, but no procedure is entirely without risk.
I’m no health care worker. My experience is in the lab. And discussion of biopsies for earlier diagnosis is, IMHO, theoretical. Get me a biopsy sample and I know what to do with it. But you don’t want me being the one in the procedure room sticking pointy things into patients to collect samples.
I doubt the overall potential benefits to the few who are diagnosed earlier outweigh the additional risks that staff and negative patients are exposed to.
But we’ve learned in this outbreak that perhaps the protective equipment used in the lab might not be what is needed in the field clinic in Africa or in a controlled American hospital for patient care where more invasive procedures are performed.
So first, for the hospital worker, is to be sure the PPE gear is suitable, particularly keeping in mind the potential for aerosol generation during a biopsy. Needle biopsies (say of a lymph node) may not pose significantly different risks to the health care workers than a blood draw. Based solely upon what I have read (Thanks Dr. Internet!) a biopsy of the liveror is slightly more involved, but not much more so. A needle biopsy of the spleen is apparently much riskier to the patient and rarely done. A surgical procedure might be needed to provide a sample for our theoretical test.
There are four categories for the patients, based upon whether they truly are positive or negative and based upon whether they test positive or negative. I would assume that no doctor would perform a biopsy test on an asymptomatic patient if there was not compelling evidence of prior ebola exposure.
Thought experiment is as follows: Positive test/Truly positive
It seems obvious to me that the patient has a greater risk from a biopsy than just a blood draw during normal times. Perhaps testing using a sample obtained from a biopsy could allow treatment to start a day or even two earlier? Maybe? Possibly? And maybe earlier treatment would justify the excess risk to the patient who is positive and who tests positive. Maybe? There is no proof and a study would be unlikely IMHO.
False Positive test/Truly negative patient
A patient who falsely tests positive would almost certainly be subjected to isolation and treatment at least until he tests negative. If the false positive was earlier due to a biopsy sample test then such patients might be subjected to more time under unnecessary isolation and treatment. The staff would be subjected to unnecessary stress.
False Negative test/Truly positive patient
This rare possibility should make everyone nervous. Any test has some small (perhaps minimally so), possibility of telling a truly ill patient that they do not have the condition. And an earlier test using a biopsy sample might tend to have a higher false negative rate. (The sample was from the left part of that lymph node which hasn’t yet been infected. The infection is already in progress in another part of that node.) Such a patient might be sent home and may tend to dismiss later symptoms leading to a higher than average amount of infection spread. And a false negative test would put medical providers at substantial risk as needed PPE might be lacking during patient care.
True negative test/Truly negative patient
Earlier confirmation may allow doctors to more quickly focus attention on the true nature of the patient’s problem. And earlier diagnosis may avoid unnecessary use of resources. Medical providers come out ahead, in general, in this scenario.
Yes, that’s exactly what I’m wondering about. While blood can certainly get on you when doing a blood draw, it doesn’t aerosolize. Contact - even ebola contact - has more of a known risk level than aerosolized ebola. I don’t know what the risk of tissue biopsies causing aerosolization might be. The idea that people aren’t contagious until symptomatic (no matter how controversial) is rather predicated on the idea that you don’t go pulling their virus laden innards out.
You may not be a “health care worker”, but I very much appreciate your perspective and your insights and explanations in this thread.
An individual exposed by needle stick is at absolutely zero risk of transferring Ebola to another individual overnight and it’s this kind of hysteria over it that gums up most reasonable approaches.
I’m not sure this individual ever developed Ebola.
My point about a blood transfusion is that such an individual would have a large viral load, even though asymptomatic in the short term…not to be confused with a needle stick exposure.
Well, I’d be 100% behind incentivizing the process, I think it’s better fought there than here, but ‘don’t make them wait for their nachos’ is a mind blowingly stupid approach to pandemic control.
We’re getting somewhere. Now, to this PCR business, if not the biopsy, and the speed/cost/practicality answer.
[Aside: why have I never seen these questions answers before in the press or from officialdom…they’re not so foreign to…]
The well-known experience of diabetes, my maybe wrong but to me an obvious question/analog: couldn’t, flat out, a person in quarantine do a needle stick or take his own blood (how much?) and slip it out the mail slot, or whatever, for the labs to work it?
Sort of ignore my above query, unless it’s to observe someone’s wants vs facts, vs. misreading the helpful posts above.
More or less because of a wish/fantasy for an accucheck-like test, once, and even if, it takes a day or three to travel from biopsy level to bloodstream level, but would save a day or two to fever body symptom level.
(But to backtrack-free associate, perhaps a doctor or medical-trained person, especially those who ought to know better [eg the bowling doctor, now called the Ebowler, I understand] if he couldn’t do a self biopsy extraction, he certainly could do a healthy blood draw before fever and other body symptoms appear.)
Are you wondering if it’s possible for a self-quarantined person to submit their own sample of body/fluid or blood for analysis?
The answer is, yes.
Note that ELISA and PCR do not technically look for live virus, and culture takes longer. One promising approach would be to test saliva,which apparently turns positive for evidence of the virus early, and of course is readily available. It’s not known how early saliva turns positive (for PCR, say) because (as far as I know) prospective studies on exposed patients have not been done. That study–and others–looks at tests run on patients already presumed to have Ebola.
As a follow up, in support of your contention, there is this from the current issue of the New England Journal of Medicine: “We have very strong reason to believe that transmission occurs when the viral load in bodily fluids is high, on the order of millions of virions per microliter. This recognition has led to the dictum that an asymptomatic person is not contagious; field experience in West Africa has shown that conclusion to be valid.”
Against your contention, there is this from the 16 October NEJM analysis of 4,500 plus cases: “The most common symptoms reported between symptom onset and case detection included fever (87.1%), fatigue (76.4%), loss of appetite (64.5%), vomiting (67.6%), diarrhea (65.6%), headache (53.4%), and abdominal pain (44.3%). Specific hemorrhagic symptoms were rarely reported (in <1% to 5.7% of patients).”
That these two articles are at odds with one another (the first taking a strong position that “an asymptomatic person is not contagious,” and the second showing data that symptoms are somewhat protean and therefore unreliable as viremia harbingers) is kind of par for the course in my field.
However I thought you might like some medical literature, even if it’s just an opinion piece, ammo for your side of the question.
Note the wording is careful: “not contagious.” This does not mean “not infectious,” as I mentioned earlier.
Rethinking this a bit… the time each cycle takes depends a bit on how big the piece of DNA is that is being duplicated. The full genetic material of the Ebola virus is small, about 17K base pairs of RNA.
So even if a test was duplicating the entire Ebola genome each PCR cycle wouldn’t take as long as 25 minutes… more like 12 minutes. So call it 6-7 hours in the extreme.
But in reality a test would only need to target some small portion of the Ebola genome - whatever is known to be unique to Ebola. Probably no more than 500 base pairs long. 500 base pairs can be duplicated in around 60 seconds. Add the time for the rest of the PCR cycle steps and realistically we’re looking at perhaps 4 minutes per cycle, so around 2 hours for the PCR to run 30 cycles.
Sample preparation and handling still takes a little bit of time call it 30 minutes. And there are more elegant ways* to effectively get a direct readout bypassing the need for a tag I previously mentioned.
So… once the sample has arrived in a fully equipped lab with everything else ready to go then a PCR test could reasonably be done in 2.5 hours.**
Likely the delay we have seen is getting the test samples transported from the hospital to an equipped lab. Most hospital labs in the US*** won’t have the specific primers or tags in stock. And, of course, there is always something that isn’t quite ready-to-go.
*Quantitative real-time PCR techniques allow for a reading as the test progresses. One such method uses fluorescent dyes. What color do you think the test tube should glow if the test is positive and Ebola is present?
** Looks like my estimate of 2.5 hours isn’t so bad. Thomas Ksiazek, a former head of the Special Pathogens Branch of the CDC estimates 3 to 4 hours total. Which for me, knowing my luck, means 7.5 hours because I’d screw it up twice and have to do it all over again.
*** There are labs in some hospitals in Liberia and Sierra Leone that do have everything right there - probes, tags, and PCR machine. But they might not have reliable electricity to run the PCR machine.
FTR, the “brave and heroic doctor” (quote from ref) lied to the police. He said he had stayed in “home quarantine” the whole time, and only admitted he had been out and about when evidence from his metrocard was exposed.
Now, to this PCR business, if not the biopsy, and the speed/cost/practicality answer.
