Cycle thresholds of positive SARS-CoV-2 tests in New Zealand

Susan Pockett made this Official Information request to Ministry of Health

The request was successful.

From: Susan Pockett

Dear Ministry of Health,

As a follow-up to my question about operational false positive rates:

(a) How many of the PCR tests for SARS-CoV-2 done in NZ to date have been scored positive?

(b) How many of these positive tests have returned a cycle threshold of 35 or more?

Yours faithfully,

Susan Pockett

Link to this

From: OIA Requests

Kia ora Susan,

 

Thank you for your request for official information received on 23^rd June
2021 for:

 

                “(a) How many of the PCR tests for SARS-CoV-2 done in NZ
to date have been scored positive?

(b) How many of these positive tests have returned a cycle threshold of 35
or more?"

 

The Ministry's reference number for your request is: H202107584.

 

As required under the Official Information Act 1982, the Ministry will
endeavour to respond to your request no later than 22^nd July 2021, being
20 working days after the day your request was received.

 

If we are unable to respond to your request within this time frame, we
will notify you of an extension of that time frame.

 

If you have any queries related to this request, please do not hesitate to
get in touch.

 

Ngâ mihi

 

OIA Services

Government Services

Office of the Director-General

Ministry of Health

E: [email address]

 

show quoted sections

Link to this

From: OIA Requests


Attachment image001.jpg
2K Download

Attachment H202107584.pdf
541K Download View as HTML


Kia ora Susan,

 

Please find attached the response for your request for official
information.

 

Ngā mihi

 

 

OIA Services

Government Services

Office of the Director-General

Ministry of Health

E: [1][email address]

 

 

show quoted sections

References

Visible links
1. mailto:[email address]

Link to this

From: OIA Requests


Attachment image002.jpg
3K Download

Attachment H202107584 reconsideration.pdf
154K Download View as HTML

Attachment CT Values with Month 3.csv.txt
38K Download View as HTML


Kia ora Sue,

 

Please find attached a response to your official information act request

 

Ngā mihi 

 

OIA Services

Government Services

Office of the Director-General

Ministry of Health

E: [1][email address]

 

 

 

show quoted sections

References

Visible links
1. mailto:[email address]

Link to this

Susan Pockett left an annotation ()

Thanks to the intervention of the Ombudsman, I have now received a text file (sadly not an excel spreadsheet, as promised)! detailing the cycle thresholds of a very large number of PCR tests -- presumably all of those scored as positive from August 2020 to September 2021. A few of the figures even report the cycle thresholds (Cts) returned by several different kinds of PCR test done on the same sample, which is interesting in that it reveals that different flavours of PCR test produce Ct results that are only slightly different.

The basic answer revealed by the dataset as a whole is that a large proportion of the Cts reported ARE, in fact, 35 or above. Given that positive tests with Cts of 35 or above are widely considered to be either "cases" that are not infectious or outright false positives, I imagine this may explain the MoH's initial refusal to reveal the figures.

I do intend to analyse this data trove properly and report it to some scientific forum, but this will take some time. Meanwhile, many thanks to the Ombudsman, who has restored a little of my faith in the law of the land.

Link to this

Susan Pockett left an annotation ()

The analysis of these data which is now posted in an article at https://www.thekiwioptimist.com/post/wha... shows that the NZ Ministry of Health has known for at least a year that the reliability of the PCR testing they administer is too low to provide any acceptable rationale for the unprecedented mandates enacted by the government on the basis of these tests. They have also known since November 2020 that all they need do to change the number of 'cases' of covid they detect is change the brand of test they use. According to the data in this release, one particular brand of test reliably delivers many more 'cases' than any of the other brands -- and many if not most of these 'cases' show as outright negative for SARS-CoV-2 when the same sample is tested using other brands of test. Since the brand used in most of the test results in the MoH database is not recorded, it is not clear how many of the 'strong positive' test results in this database were obtained using the suspect brand of test.

In short, these MoH data suggest -- and material published in the British Medical Journal definitively shows -- that in some circumstances, both PCR and Rapid Antigen tests deliver a staggeringly high percentage of false positive results.

Incidentally, apologies for the font in the aforementioned web post. I am far from a novice at science, but I am a complete novice at blogging -- and it turns out that Wix is an extraordinarily difficult and unintuitive brand of blogging software, to the extent that I was completely unable to perform what one would think should be the simple act of changing this font!

Link to this

Things to do with this request

Anyone:
Ministry of Health only: