Now testing is opt-out, not opt-in

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Does anyone have a source on the false positive rate for these tests? Genuine question. There are lots of anecdotes like rice university, and the two “fleeting contact” people in the Australia outbreak, but is there any robust data on it?

It's not enough for you that a DCUM poster saw it on FB or heard about it on another forum? You want "DATA"!!!???

Kidding of course. Welcome to the DCUM echo chamber.

Research/explanation/support from experts has been provided already on this thread, and on the linked thread. People just don’t bother to read a thread.

The article quoted as research support is based on data from last April, prior to Delta. You'd need to take into account the much higher contagion rate of delta, which would negate some of her statements about transmissibility.

Additionally, the research does not refer to the particular test being given and its false positive rate. You have to assume there might have been advances in both the testing itself and the accuracy of the false negative or positive measurements. I want to know what exactly those rates are for that test specifically.

The article mentions a "saliva PCR" test, which is what DCPS is using.

Not all tests are the same; you need to know the manufacturer. For example, the Binax and the Ellume rapid at-home tests have different false positive and false negative rates.

Also, statistically, the choice to tighten up on false positives means more false negatives, and vice versa.

For medical tests, generally false negatives are considered a bigger problem — you don’t want to miss an actual case, while positives can just be retested for confirmation.

Yes, we know. We don't know the specific tests that DCPS is using, we just now -- according to the consent form -- that they are saliva PCR. As noted, in the research cited above, even tests with what one would think of as a "good" efficiency rate (like 95%) are still problematic for false positives in a "low" prevalence setting (where "low" is what we have in DC now) (notably, even double what we have now, you'd still have a majority of your positive tests be false positives).

We do know the specific tests. DCPS has announced elsewhere. They are SHiELD Saliva tests

Those actually have exceedingly low false positive but very high false negatives. Anyway, we opted out. I don’t want that exposure for my kids. They have to stay in line then enter a room then interact with a nurse where 50+ other kids did within the same hour and who are all unmasked to take the test and spitting to take the test?! Yea, NO THaNK YOU!

[Anonymous]

Anonymous wrote:For those who don't like the date of April, 2020, here's another article from infectious disease specialists from July, 2021:

https://www.usnews.com/news/health-news/articles/2021-07-14/why-covid-19-screening-should-be-used-sparingly-in-schools

Why We Shouldn’t Blindly Screen Students for COVID-19 This Fall
When case rates are low, the majority – and sometimes even the vast majority – of positive test results are false-positives.

The DESE testing program and others across the state and across the country have shown us that the probability of COVID-19 in asymptomatic students attending in-person learning was consistently low – less than 0.5% – even before widespread vaccination. Using 0.5 as a (very) generous overestimate and a close-to-perfect (99% specific) diagnostic test, that means for every one true positive test, three will be false-positive. The true specificity of some polymerase chain reaction (PCR) tests is probably closer to 95% (in other words, still very good, but not quite so close to perfect). This more realistic estimate increases the proportion of false-positives test results even more – up to 14 false-positives for every real case of COVID-19 identified by the screening program. As case rates continue to decline, the ratio of real cases to false-positives only gets worse (and worse). Assuming a rate of 1 in 1,000 or 0.1% and a nearly perfect test, there are 14 false-positive tests for every real case found by a screening testing program, and 71 if we use the more realistic estimate of 95% specificity.

Case rates are SUBSTANTIAL in DC.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Does anyone have a source on the false positive rate for these tests? Genuine question. There are lots of anecdotes like rice university, and the two “fleeting contact” people in the Australia outbreak, but is there any robust data on it?

It's not enough for you that a DCUM poster saw it on FB or heard about it on another forum? You want "DATA"!!!???

Kidding of course. Welcome to the DCUM echo chamber.

Research/explanation/support from experts has been provided already on this thread, and on the linked thread. People just don’t bother to read a thread.

The article quoted as research support is based on data from last April, prior to Delta. You'd need to take into account the much higher contagion rate of delta, which would negate some of her statements about transmissibility.

Additionally, the research does not refer to the particular test being given and its false positive rate. You have to assume there might have been advances in both the testing itself and the accuracy of the false negative or positive measurements. I want to know what exactly those rates are for that test specifically.

The article mentions a "saliva PCR" test, which is what DCPS is using.

Not all tests are the same; you need to know the manufacturer. For example, the Binax and the Ellume rapid at-home tests have different false positive and false negative rates.

Also, statistically, the choice to tighten up on false positives means more false negatives, and vice versa.

For medical tests, generally false negatives are considered a bigger problem — you don’t want to miss an actual case, while positives can just be retested for confirmation.

Yes, we know. We don't know the specific tests that DCPS is using, we just now -- according to the consent form -- that they are saliva PCR. As noted, in the research cited above, even tests with what one would think of as a "good" efficiency rate (like 95%) are still problematic for false positives in a "low" prevalence setting (where "low" is what we have in DC now) (notably, even double what we have now, you'd still have a majority of your positive tests be false positives).

We do know the specific tests. DCPS has announced elsewhere. They are SHiELD Saliva tests

Those actually have exceedingly low false positive but very high false negatives. Anyway, we opted out. I don’t want that exposure for my kids. They have to stay in line then enter a room then interact with a nurse where 50+ other kids did within the same hour and who are all unmasked to take the test and spitting to take the test?! Yea, NO THaNK YOU!

And across cohorts. It’s much worse than the cafeteria issue. If you have even a few of those students who are positive, the cumulative exposure from even the limited time is sufficient to contaminate all

[Anonymous]

Anonymous wrote:

Anonymous wrote:
Testing should NOT be optional. Every one, regardless of vaccinated status, should be tested every single week during the school year, and failing that, should not be admitted to school until a negative PCR test can be provided.

Nope. That's not the policy. Many of us are opting out.

Why???

[Anonymous]

Anonymous wrote:

Anonymous wrote:For those who don't like the date of April, 2020, here's another article from infectious disease specialists from July, 2021:

https://www.usnews.com/news/health-news/articles/2021-07-14/why-covid-19-screening-should-be-used-sparingly-in-schools

Why We Shouldn’t Blindly Screen Students for COVID-19 This Fall
When case rates are low, the majority – and sometimes even the vast majority – of positive test results are false-positives.

The DESE testing program and others across the state and across the country have shown us that the probability of COVID-19 in asymptomatic students attending in-person learning was consistently low – less than 0.5% – even before widespread vaccination. Using 0.5 as a (very) generous overestimate and a close-to-perfect (99% specific) diagnostic test, that means for every one true positive test, three will be false-positive. The true specificity of some polymerase chain reaction (PCR) tests is probably closer to 95% (in other words, still very good, but not quite so close to perfect). This more realistic estimate increases the proportion of false-positives test results even more – up to 14 false-positives for every real case of COVID-19 identified by the screening program. As case rates continue to decline, the ratio of real cases to false-positives only gets worse (and worse). Assuming a rate of 1 in 1,000 or 0.1% and a nearly perfect test, there are 14 false-positive tests for every real case found by a screening testing program, and 71 if we use the more realistic estimate of 95% specificity.

Case rates are SUBSTANTIAL in DC.

Still not getting it, but I'll stop trying.

[Anonymous]

Rather than opting out, the people concerned about false positives should be clarifying what happens once a positive is reported. Is it immediately followed up with a PCR test?

[Anonymous]

Anonymous wrote:Rather than opting out, the people concerned about false positives should be clarifying what happens once a positive is reported. Is it immediately followed up with a PCR test?

This is important, especially if there is a high false positive rate. Also knowing what the school will do if a school, or privately administered, follow-up PCR test is negative following a positive at school will be interesting. I'm absolutely not opting out of testing, but it would really suck for my kid or one of their classmates to cause others to quarantine on faulty results. Given these stats, why can't they just do the nasal swab rapids? My young child's summer program did the nasal swab tests and it was a non-issue.

[Anonymous]

Anonymous wrote:Rather than opting out, the people concerned about false positives should be clarifying what happens once a positive is reported. Is it immediately followed up with a PCR test?

If last year is an indication, no, it is not followed up with a RT-PCR test (I think you mean a RT-PCR test; the saliva tests are also PCR tests).

I'd be happy if there were established protocols that OSSE has provided regarding re-testing, but I have not seen any in the OSSE school handbook.

[Anonymous]

Anonymous wrote:

Anonymous wrote:Rather than opting out, the people concerned about false positives should be clarifying what happens once a positive is reported. Is it immediately followed up with a PCR test?

This is important, especially if there is a high false positive rate. Also knowing what the school will do if a school, or privately administered, follow-up PCR test is negative following a positive at school will be interesting. I'm absolutely not opting out of testing, but it would really suck for my kid or one of their classmates to cause others to quarantine on faulty results. Given these stats, why can't they just do the nasal swab rapids? My young child's summer program did the nasal swab tests and it was a non-issue.

When you say "non-issue" what does that mean? How do you know there were no false positives? Was there retesting, even for RT-PCR?

[Anonymous]

Anonymous wrote:

Anonymous wrote:Rather than opting out, the people concerned about false positives should be clarifying what happens once a positive is reported. Is it immediately followed up with a PCR test?

If last year is an indication, no, it is not followed up with a RT-PCR test (I think you mean a RT-PCR test; the saliva tests are also PCR tests).

I'd be happy if there were established protocols that OSSE has provided regarding re-testing, but I have not seen any in the OSSE school handbook.

Last year were not saliva tests.

[Anonymous]

Anonymous wrote:

Anonymous wrote:Rather than opting out, the people concerned about false positives should be clarifying what happens once a positive is reported. Is it immediately followed up with a PCR test?

This is important, especially if there is a high false positive rate. Also knowing what the school will do if a school, or privately administered, follow-up PCR test is negative following a positive at school will be interesting. I'm absolutely not opting out of testing, but it would really suck for my kid or one of their classmates to cause others to quarantine on faulty results. Given these stats, why can't they just do the nasal swab rapids? My young child's summer program did the nasal swab tests and it was a non-issue.

But it’s a limited quarantine, right? I thought they’d changed what it means to be a “close contact” so much that no one is going to be considered a. Lose contact, except for maybe during lunch, but then they’re not tracking who sits where.

I’m honestly more concerned about having to keep my kid home when she has a cold, even if we get a negative PCR test. Zero tolerance for lingering cough or runny nose is going to be rough for a lot of people.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Rather than opting out, the people concerned about false positives should be clarifying what happens once a positive is reported. Is it immediately followed up with a PCR test?

If last year is an indication, no, it is not followed up with a RT-PCR test (I think you mean a RT-PCR test; the saliva tests are also PCR tests).

I'd be happy if there were established protocols that OSSE has provided regarding re-testing, but I have not seen any in the OSSE school handbook.

Last year were not saliva tests.

These saliva tests seem highly accurate actually. High specificity (>99%), so very few false positives. Again, a secondary test should help mitigate those.

https://www.shieldt3.com/

[Anonymous]

Anonymous wrote:Rather than opting out, the people concerned about false positives should be clarifying what happens once a positive is reported. Is it immediately followed up with a PCR test?

Exactly. It's like you're not seeing the forest for the trees here.

It also says on the website of the test provider that they test positives again themselves.
I hope that after that a positive is referred to a PCR test, which is taken as more reliable.

[Anonymous]

Anonymous wrote:

Anonymous wrote:Rather than opting out, the people concerned about false positives should be clarifying what happens once a positive is reported. Is it immediately followed up with a PCR test?

This is important, especially if there is a high false positive rate. Also knowing what the school will do if a school, or privately administered, follow-up PCR test is negative following a positive at school will be interesting. I'm absolutely not opting out of testing, but it would really suck for my kid or one of their classmates to cause others to quarantine on faulty results. Given these stats, why can't they just do the nasal swab rapids? My young child's summer program did the nasal swab tests and it was a non-issue.

Actually these are supposed to be more reliable than a rapid nasal swab test. I'm not sure why they aren't just doing regular PCR, but, the processing time is much longer and the kid may have infected their whole class in the 2 days they wait for the results, so perhaps that's why.

[Anonymous]

Hopefully DC will benefit from other local distracts going back first by gaining some wisdom on what not to do. Fairfax county schools sound like a mess with no one knowing what the policies are.

https://www.fairfaxtimes.com/articles/fairfax_county/fcps-parents-grow-frustrated-by-quarantine-protocols/article_182e9362-0693-11ec-a3d8-d3e3480d933a.html