Now testing is opt-out, not opt-in

[Anonymous]

Shield test's negativity (or "specificity") rate is 98.9%, according to themselves (slide 4): https://www.iasaedu.org/cms/lib/IL01923163/Centricity/Domain/4/SHIELD%20IL%20IDPH%20overview%20050621.pdf

That means that the test correctly returns a negative result 98.9% of the time when the person is truly negative, and returns a "false positive" 1.1% of the time.

The Washington Post article posted earlier:

"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."

This study uses a slightly less specific test (the BinaxNow rapid test), which has a specificity of 98.5% (https://abbott.mediaroom.com/2020-08-26-Abbotts-Fast-5-15-Minute-Easy-to-Use-COVID-19-Antigen-Test-Receives-FDA-Emergency-Use-Authorization-Mobile-App-Displays-Test-Results-to-Help-Our-Return-to-Daily-Life-Ramping-Production-to-50-Million-Tests-a-Month)

The ASM study shows that with a similar test specificity, and low PREVALENCE rates (0.1% to 1.0%), the percentage of positive tests that are false is between 60 and 94% (it's lower when the prevalence is higher). https://asm.org/Articles/2020/November/SARS-CoV-2-Testing-Sensitivity-Is-Not-the-Whole-St

SO WHAT IS PREVALENCE DURING DELTA?

During delta and with twice weekly testing (so a lot of tests), the UK found a prevalence rate in schools of 0.27% in primary schools and 0.42% in secondary schools in June, 2021. Note that they didn't mask, and don't have vaccination approval for the 12-15 year olds. They did of course do other mitigation measures related to the testing. I offer this as it seems to be one of the only studies of PREVALENCE in schools, during delta, where there was lots of testing. https://www.gov.uk/government/news/covid-19-study-finds-lower-prevalence-in-schools

PREVALENCE outside of schools in the UK during early delta (June 24 to July 12) was 0.63%. (https://www.medicalnewstoday.com/articles/covid-19-in-england-rising-infections-as-delta-variant-takes-hold#Delta-surge).

How does that PREVALENCE compare to covid CASE RATES (which is what we all obsessively look at in DC)? Between June 24 and July 12, UK’s 7-day case rates per 100,000 went from 145 to 358 (https://coronavirus.data.gov.uk/details/cases). In DC terms (of cases per day instead of 7 days) that is about 20/100,000 per day to 51/100,000 per day.

The point being that we likely have low prevalence + Probably even lower in schools as that's been true consistently + test has a specificity greater than 1% = whole lot of false positives.

[Anonymous]

We opted out. My 16 year old son has been double Vaxxed for months and will get a booster when it’s his turn. He masks. He is mindful of distancing and washing hands and being alert to those around him who might be coughing or yelling (spewing particles). I don’t trust the schools to give the tests properly or have the results tested properly or to have the correct student’s results associated with the correct student.

[Anonymous]

Anonymous wrote:

Anonymous wrote:What is the current rate in DC? Is it a low rate?

DC is in the category “substantial spread” according to CDC. Only other category is “high.” Over the past month, the daily case rate has doubled. [/quote

And? Could it be more people got tested that had not even a runny nose and thought Delta - I am not vaxed! DC rates are climbing because people aren’t vaxed.

[Anonymous]

Anonymous wrote:Shield test's negativity (or "specificity") rate is 98.9%, according to themselves (slide 4): https://www.iasaedu.org/cms/lib/IL01923163/Centricity/Domain/4/SHIELD%20IL%20IDPH%20overview%20050621.pdf

That means that the test correctly returns a negative result 98.9% of the time when the person is truly negative, and returns a "false positive" 1.1% of the time.

The Washington Post article posted earlier:

"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."

This study uses a slightly less specific test (the BinaxNow rapid test), which has a specificity of 98.5% (https://abbott.mediaroom.com/2020-08-26-Abbotts-Fast-5-15-Minute-Easy-to-Use-COVID-19-Antigen-Test-Receives-FDA-Emergency-Use-Authorization-Mobile-App-Displays-Test-Results-to-Help-Our-Return-to-Daily-Life-Ramping-Production-to-50-Million-Tests-a-Month)

The ASM study shows that with a similar test specificity, and low PREVALENCE rates (0.1% to 1.0%), the percentage of positive tests that are false is between 60 and 94% (it's lower when the prevalence is higher). https://asm.org/Articles/2020/November/SARS-CoV-2-Testing-Sensitivity-Is-Not-the-Whole-St

SO WHAT IS PREVALENCE DURING DELTA?

During delta and with twice weekly testing (so a lot of tests), the UK found a prevalence rate in schools of 0.27% in primary schools and 0.42% in secondary schools in June, 2021. Note that they didn't mask, and don't have vaccination approval for the 12-15 year olds. They did of course do other mitigation measures related to the testing. I offer this as it seems to be one of the only studies of PREVALENCE in schools, during delta, where there was lots of testing. https://www.gov.uk/government/news/covid-19-study-finds-lower-prevalence-in-schools

PREVALENCE outside of schools in the UK during early delta (June 24 to July 12) was 0.63%. (https://www.medicalnewstoday.com/articles/covid-19-in-england-rising-infections-as-delta-variant-takes-hold#Delta-surge).

How does that PREVALENCE compare to covid CASE RATES (which is what we all obsessively look at in DC)? Between June 24 and July 12, UK’s 7-day case rates per 100,000 went from 145 to 358 (https://coronavirus.data.gov.uk/details/cases). In DC terms (of cases per day instead of 7 days) that is about 20/100,000 per day to 51/100,000 per day.

The point being that we likely have low prevalence + Probably even lower in schools as that's been true consistently + test has a specificity greater than 1% = whole lot of false positives.

Sigh. Didn’t even look at this particular test’s specificity plus secondary testing by this lab as a mitigant for false positives. DC has actually entered into a pretty promising relationship here. Wish it was better publicized though.

[Anonymous]

Anonymous wrote:We opted out. My 16 year old son has been double Vaxxed for months and will get a booster when it’s his turn. He masks. He is mindful of distancing and washing hands and being alert to those around him who might be coughing or yelling (spewing particles). I don’t trust the schools to give the tests properly or have the results tested properly or to have the correct student’s results associated with the correct student.

Gee it’s a wonder you trust the school to teach your child.

[Anonymous]

Anonymous wrote:We opted out. My 16 year old son has been double Vaxxed for months and will get a booster when it’s his turn. He masks. He is mindful of distancing and washing hands and being alert to those around him who might be coughing or yelling (spewing particles). I don’t trust the schools to give the tests properly or have the results tested properly or to have the correct student’s results associated with the correct student.

DOH doesn’t want vaccinated kids to participate, so all is well.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:I hope this leads to a "test and stay" policy, where instead of quarantining, kids can just get tested every day. UK found that this was equally as effective as quarantine.

https://www.ox.ac.uk/news/2021-07-23-daily-contact-covid-19-testing-students-effective-controlling-transmission-schools

This is really what they need to do. Statistically, most positives will be false.

Yeah, I would be for asymptomatic random testing if DC wasn't idiotic about testing.

Ditto. If they did test and stay I would not opt out. But I’m opting out. If kid is actually ill I will test. Oh what is that you say — most kids have no symptoms?! Hmmm. Sounds like they are fine to go to school.

Wow. Just saying the quiet part aloud now. You are perfectly fine with your child spreading covid to other kids.

[Anonymous]

Why do people keep saying stuff like “DC is idiotic about testing”?

DC has done a great job of Covid testing! I have a lot of complaints about DC government, but I’ve only been impressed with their Covid testing set-up. Easy to access, efficient, and accurate.

[Anonymous]

Anonymous wrote:

Anonymous wrote:Shield test's negativity (or "specificity") rate is 98.9%, according to themselves (slide 4): https://www.iasaedu.org/cms/lib/IL01923163/Centricity/Domain/4/SHIELD%20IL%20IDPH%20overview%20050621.pdf

That means that the test correctly returns a negative result 98.9% of the time when the person is truly negative, and returns a "false positive" 1.1% of the time.

The Washington Post article posted earlier:

"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."

This study uses a slightly less specific test (the BinaxNow rapid test), which has a specificity of 98.5% (https://abbott.mediaroom.com/2020-08-26-Abbotts-Fast-5-15-Minute-Easy-to-Use-COVID-19-Antigen-Test-Receives-FDA-Emergency-Use-Authorization-Mobile-App-Displays-Test-Results-to-Help-Our-Return-to-Daily-Life-Ramping-Production-to-50-Million-Tests-a-Month)

The ASM study shows that with a similar test specificity, and low PREVALENCE rates (0.1% to 1.0%), the percentage of positive tests that are false is between 60 and 94% (it's lower when the prevalence is higher). https://asm.org/Articles/2020/November/SARS-CoV-2-Testing-Sensitivity-Is-Not-the-Whole-St

SO WHAT IS PREVALENCE DURING DELTA?

During delta and with twice weekly testing (so a lot of tests), the UK found a prevalence rate in schools of 0.27% in primary schools and 0.42% in secondary schools in June, 2021. Note that they didn't mask, and don't have vaccination approval for the 12-15 year olds. They did of course do other mitigation measures related to the testing. I offer this as it seems to be one of the only studies of PREVALENCE in schools, during delta, where there was lots of testing. https://www.gov.uk/government/news/covid-19-study-finds-lower-prevalence-in-schools

PREVALENCE outside of schools in the UK during early delta (June 24 to July 12) was 0.63%. (https://www.medicalnewstoday.com/articles/covid-19-in-england-rising-infections-as-delta-variant-takes-hold#Delta-surge).

How does that PREVALENCE compare to covid CASE RATES (which is what we all obsessively look at in DC)? Between June 24 and July 12, UK’s 7-day case rates per 100,000 went from 145 to 358 (https://coronavirus.data.gov.uk/details/cases). In DC terms (of cases per day instead of 7 days) that is about 20/100,000 per day to 51/100,000 per day.

The point being that we likely have low prevalence + Probably even lower in schools as that's been true consistently + test has a specificity greater than 1% = whole lot of false positives.

Sigh. Didn’t even look at this particular test’s specificity plus secondary testing by this lab as a mitigant for false positives. DC has actually entered into a pretty promising relationship here. Wish it was better publicized though.

The particular tests specificity is literally cited above.

[Anonymous]

Anonymous wrote:Why do people keep saying stuff like “DC is idiotic about testing”?

DC has done a great job of Covid testing! I have a lot of complaints about DC government, but I’ve only been impressed with their Covid testing set-up. Easy to access, efficient, and accurate.

I strongly agree with you. The free tests from the libraries are easy and remarkably fast. I took one and the initial text said I would have the results in 5 business days - and this was on a Friday afternoon. I ended up getting the result on Sunday morning. You can take up to 5 of the tests home with you per day to save for when needed.

[Anonymous]

Anonymous wrote:Why do people keep saying stuff like “DC is idiotic about testing”?

DC has done a great job of Covid testing! I have a lot of complaints about DC government, but I’ve only been impressed with their Covid testing set-up. Easy to access, efficient, and accurate.

We are talking about DCPS’s asymptomatic testing program and how it deals with positive tests. Try reading any of the multiple threads on this.

[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.

Thank you for posting this article.

[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.

Thank you for posting this article.

That article is pre-Delta and describes an environment of declining case rates.

[Anonymous]

Anonymous wrote:

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.

Thank you for posting this article.

That article is pre-Delta and describes an environment of declining case rates.

The in school rates quoted here were similar in the UK with delta and without masking.

[Anonymous]

Anonymous wrote:

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.

Thank you for posting this article.

That article is pre-Delta and describes an environment of declining case rates.

Delta doesn’t change math.