Now testing is opt-out, not opt-in

[Anonymous]

I have not heard this much grumbling about false positives outside of a pro-Trump forum. Are false positives really a concern?

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

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 are you opting out?

Its a waste. Kids are essentially at zero risk. 170,000 kids in DC and zero deaths. It's a waste of time.

It’s not a waste at all. Knowing if your child is positive helps you avoid breakthrough Covid.

DP. How so? I’m not going to exile my kid from the house. I’m vaccinated and not worried about severe illness.

[Anonymous]

Anonymous wrote:I have not heard this much grumbling about false positives outside of a pro-Trump forum. Are false positives really a concern?

Yes, as they have severe consequences, not just for the positive kid. And this has nothing to do with Trump. Quit trying to politicize everything and get out of your Twitter bubble.

[Anonymous]

Anonymous wrote:

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.

Up your nose, lady. The tests are invasive.

\
No they aren't. They are the same test DC.gov has free at every library. The swab is NOT deep and you run it three times aroun dinside of nose.

No, they aren't nasal swabs at all (which is what is ab the library). They are the (much more likely to produce false positive) saliva PCR.

[Anonymous]

Anonymous wrote:I have not heard this much grumbling about false positives outside of a pro-Trump forum. Are false positives really a concern?

They'd be like 80% of the positives, according to math.

[Anonymous]

Anonymous wrote:I have not heard this much grumbling about false positives outside of a pro-Trump forum. Are false positives really a concern?

That noted Trumper, Monica Gandhi:

https://www.washingtonpost.com/outlook/2021/04/19/schools-covid-testing-cost/

Written in April, 2021:

But there are downsides to systematic testing that have been insufficiently considered, including costs, lost learning time, logistics and stress for those subjected to such a regime. False-positive results — which say you are infected when you aren’t — pose particular problems. Overall, this kind of widespread testing fails cost-benefit analysis: It will drain already insufficient public school resources while doing little to improve safety. And with nearly 80 percent of teachers and school staffers vaccinated with their first dose, the argument for testing grows even weaker.


First, classrooms have thankfully been found — in studies examining schools in multiple states — to be places of limited disease transmission, compared with communities at large. The rate of transmission within schools from individuals who test positive has been estimated to be on the order of 0.5 percent to 0.7 percent (and this includes people exhibiting symptoms).

A rate that low implies that a testing regimen would need to identify roughly 200 infected people to prevent one person from transmitting the disease in school. It would take an awful lot of tests to achieve those numbers. In New York City, where more than 234,000 asymptomatic students and staff members across approximately 1,600 schools were tested last fall, the overall rate of positive tests was only 0.4 percent. That suggests that — even during a time of high community spread — about 40,000 tests among asymptomatic individuals would need to be performed to prevent one in-school transmission.

And how accurate are these tests? Rapid antigen and saliva PCR tests, which are frequently used in schools, can have a false positive rate of 1 or 2 percent. That may sound low, but statisticians know that, when testing in a setting of low prevalence of disease, even a single-digit false-positive rate can be extremely problematic.


The current prevalence rate for the coronavirus in the United States is roughly 15 cases per 10,000 people per week. (Prevalence in schools tends to be similar to, or lower than, that in the surrounding community.) If you give 10,000 people a test that produces false positives 2 percent of the time, that means you might get 215 positives: 15 true positives and 200 false positives. In other words, more than 90 percent of the positive test results will be incorrect.

[Anonymous]

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?

The rate of false positives appears low on the surface. But the problem is that when there is low community prevalence, the odds of any positive result being false go up. The math isn't immediately intuitive, but if you think about it for a second, you'll get it. Basically if the chance of covid is 1/1000, and the chance of a false positive is 1/100, then it's MUCH more likely that you have a false positive than you have covid.

Now, if the consequences of a false positive are minimal, then NBD. But the problem is that the consequences of a false positive are currently considerable, because the child and possilbly the entire class will have to quarantine.

The answer to this problem IMO is more testing. If we had a "test to stay" policy where close contacts just tested every day and didn't have to quarantine, then the primary negative consequence disappears. Similarly, a positive rapid followed by a negative PCR should allow the child to return to school immediately (assuming no symptoms consistent with covid of course). That would mean the consequences of a false positive are drastically reduced to just missing maybe 2 days of school.

Well, for better of for worse, there is not low community prevalence in D.C. now.

[Anonymous]

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?

The rate of false positives appears low on the surface. But the problem is that when there is low community prevalence, the odds of any positive result being false go up. The math isn't immediately intuitive, but if you think about it for a second, you'll get it. Basically if the chance of covid is 1/1000, and the chance of a false positive is 1/100, then it's MUCH more likely that you have a false positive than you have covid.

Now, if the consequences of a false positive are minimal, then NBD. But the problem is that the consequences of a false positive are currently considerable, because the child and possilbly the entire class will have to quarantine.

The answer to this problem IMO is more testing. If we had a "test to stay" policy where close contacts just tested every day and didn't have to quarantine, then the primary negative consequence disappears. Similarly, a positive rapid followed by a negative PCR should allow the child to return to school immediately (assuming no symptoms consistent with covid of course). That would mean the consequences of a false positive are drastically reduced to just missing maybe 2 days of school.

Well, for better of for worse, there is not low community prevalence in D.C. now.

Sigh. It's the same argument as always. No, for the math of the tests, what we have right now is "low community prevalence."

[Anonymous]

Anonymous wrote:

Anonymous wrote:I have not heard this much grumbling about false positives outside of a pro-Trump forum. Are false positives really a concern?

That noted Trumper, Monica Gandhi:

https://www.washingtonpost.com/outlook/2021/04/19/schools-covid-testing-cost/

Written in April, 2021:

But there are downsides to systematic testing that have been insufficiently considered, including costs, lost learning time, logistics and stress for those subjected to such a regime. False-positive results — which say you are infected when you aren’t — pose particular problems. Overall, this kind of widespread testing fails cost-benefit analysis: It will drain already insufficient public school resources while doing little to improve safety. And with nearly 80 percent of teachers and school staffers vaccinated with their first dose, the argument for testing grows even weaker.


First, classrooms have thankfully been found — in studies examining schools in multiple states — to be places of limited disease transmission, compared with communities at large. The rate of transmission within schools from individuals who test positive has been estimated to be on the order of 0.5 percent to 0.7 percent (and this includes people exhibiting symptoms).

A rate that low implies that a testing regimen would need to identify roughly 200 infected people to prevent one person from transmitting the disease in school. It would take an awful lot of tests to achieve those numbers. In New York City, where more than 234,000 asymptomatic students and staff members across approximately 1,600 schools were tested last fall, the overall rate of positive tests was only 0.4 percent. That suggests that — even during a time of high community spread — about 40,000 tests among asymptomatic individuals would need to be performed to prevent one in-school transmission.

And how accurate are these tests? Rapid antigen and saliva PCR tests, which are frequently used in schools, can have a false positive rate of 1 or 2 percent. That may sound low, but statisticians know that, when testing in a setting of low prevalence of disease, even a single-digit false-positive rate can be extremely problematic.


The current prevalence rate for the coronavirus in the United States is roughly 15 cases per 10,000 people per week. (Prevalence in schools tends to be similar to, or lower than, that in the surrounding community.) If you give 10,000 people a test that produces false positives 2 percent of the time, that means you might get 215 positives: 15 true positives and 200 false positives. In other words, more than 90 percent of the positive test results will be incorrect.

To help with math:

The 90% false positives in the article is when there were 15 cases per 10,000 per week. Which is 150 per 100,000 per week.

DC is at about 23/100,000 per day, which translates roughly to 161 per 100,000 per week. So roughly the same in the article, when it is discussion "low community prevalence."

[Anonymous]

Next up: The arguments that:

1) math doesn't work because delta
2) math is heartless and doesn't care about people

[Anonymous]

Anonymous wrote:

Anonymous wrote:I have not heard this much grumbling about false positives outside of a pro-Trump forum. Are false positives really a concern?

Yes, as they have severe consequences, not just for the positive kid. And this has nothing to do with Trump. Quit trying to politicize everything and get out of your Twitter bubble.

Failing to test actual positives has more severe consequences.

[Anonymous]

This is interesting. Regardless of vaccination status everybody at my kids private school has to test before school starts and there will be weekly testing. We were able to have in person school last academic year because of testing...there were no false positives.

[Anonymous]

Anonymous wrote:This is interesting. Regardless of vaccination status everybody at my kids private school has to test before school starts and there will be weekly testing. We were able to have in person school last academic year because of testing...there were no false positives.

You know this because...? Also were you using rapid tests or nasal-swab PCR?

I had a friend whose kid tested positive in a rapid test (one that takes several hours, like those DCPS is using, not the 10-minute tests). Later that day, on a nasal swab PCR, kid tested negative. Repeatedly tested negative after that via PCR. Didn't matter, kid had to quarantine for two weeks. Kid's younger sibling tested negative. Parents tested negative. DOH didn't care about the later (better) negative tests.

Point being, there's no way that anyone is proposing to prove that a false positive is actually false. So anyone that tests positive is assumed to just be positive, period.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:I have not heard this much grumbling about false positives outside of a pro-Trump forum. Are false positives really a concern?

Yes, as they have severe consequences, not just for the positive kid. And this has nothing to do with Trump. Quit trying to politicize everything and get out of your Twitter bubble.

Failing to test actual positives has more severe consequences.

Depriving children of education repeatedly and for long periods of time resulting from a ton of false positives is extremely detrimental.

[Anonymous]

Anonymous wrote:

Anonymous wrote:This is interesting. Regardless of vaccination status everybody at my kids private school has to test before school starts and there will be weekly testing. We were able to have in person school last academic year because of testing...there were no false positives.

You know this because...? Also were you using rapid tests or nasal-swab PCR?

I had a friend whose kid tested positive in a rapid test (one that takes several hours, like those DCPS is using, not the 10-minute tests). Later that day, on a nasal swab PCR, kid tested negative. Repeatedly tested negative after that via PCR. Didn't matter, kid had to quarantine for two weeks. Kid's younger sibling tested negative. Parents tested negative. DOH didn't care about the later (better) negative tests.

Point being, there's no way that anyone is proposing to prove that a false positive is actually false. So anyone that tests positive is assumed to just be positive, period.

+1