Sensible questions about PCR test unanswered

 Woman kept in managed isolation after refusing Covid-19 test

An Australian woman who's being kept in managed isolation for refusing to get a Covid-19 test says she just wants more information before agreeing.

Radio NZ,

20 February, 2021

Lucinda Baulch has been at the Grand Mercure in Wellington for 25 days while she waits for scientific evidence of the PCR tests safety and effectiveness.

The woman, who is a qualified vet nurse, said she had requested additional information from the facility - but had so far not been provided with any.

Once presented with that information she would get a Covid-swab - but until then she could not give informed consent, she said.

"As someone with a medical background and knowing the importance of informed consent, for my own peace of mind I really need that informed consent, I'm entitled to it, it's a right, it's an obligation of the party offering a consent form. For me, that's quite an important step."

Baulch said the longest they could keep her in isolation was 28 days and once released she planned to take it to court.

"The New Zealand government is clearly very confident in the protocol they are using, and that's fantastic, get me on the same page.

"Because if you can prove with evidence, I am a loyal advocate, that's the thing, at the moment I just haven't had the assurances.

"I was very surprised with the lack of response or attempt to provide me with the information."

Baulch said she had seen research from Portugal where a court had ruled the PCR swab was 97 percent ineffective.

If there was strong scientific evidence that proved the theory otherwise, Baulch said she would consent to the swab.

She wanted to know if New Zealand was using the same test as was mentioned in the Portuguese ruling.

Baulch is also a foster carer and said Australian Child Services organised for her to bring three children over to caregivers here.

The three children she travelled with tested negative for Covid-19 and were allowed to leave - and despite being in the same bubble she was not.

Baulch argued everyone around her had no symptoms and was 14 days free during the 14 days so she should be allowed to return to Australia.

She said she believed the children's results were accurate, but did not consent to one herself.

A Ministry of Health spokesperson said the swab used was considered the optimal sample type for RT-PCR testing which was consider the gold standard for the detection of Covid-19.

"This swab type will obtain the optimal sample required and is the preferred collection method for both symptomatic and asymptomatic testing due to its higher sensitivity in detecting the virus.

"If someone does not have a PCR test or a heath check at all, it is not possible to assess whether they are Covid free.

"A total of 1.6 million tests have been taken in MIQ facilities, staff at our borders and in the community. It is safe and effective."

MIQ conditions

A Managed Isolation and Quarantine spokesperson said in a statement that "everyone entering an isolation or quarantine facility is provided with a welcome pack, which includes information about the tests they are required to have, when and how they are taken, and what happens if the results are positive or negative". It is currently being updated to include information about day one testing and recent changes to processes.

"When returnees arrive at an isolation facility they are given information that they are legally required to stay in the isolation facility for a minimum of 14 days. This starts from the time and date they arrive in New Zealand."

In nearly all cases they need a negative Covid-19 test and confirmation from a Medical Officer of Health or a Health Protection Officer that they are a low risk before being allowed to leave the facility, they said.

If a person refuses a day 12 test they have to stay in isolation or quarantine for at least another 10 days, this also applies to anyone else who is in their isolation bubble.

"People refusing their day 12 test are offered a test each day of their extended stay. If they agree to a test, return a negative result and meet the standard exit health criteria ... they would be able to leave without having to remain the full 22 days.

"After 22 days, they would still have to meet the standard exit health criteria (without a test) in order to leave. The maximum time a person who is in a bubble of one and is asymptomatic can be required to remain in an isolation facility under the Quarantine Order is 28 days."

This is Jacinda's "offer" - from last year

Both the Australian health authorities and the US CDC inform people about the limitations of the PCR tests. 

This is what the NZ Ministry of Health information says.

I don't think it is going to mollify anyone asking real questions

The accuracy of test results

The viral test for COVID-19 is accurate when taken in ideal conditions. A recent laboratory study found that different COVID-19 testing kits correctly detected COVID-19 in samples more than 95% (and frequently 100%) of the time. When tests were done on samples without the virus, the tests correctly gave a negative result 96% of the time. 

Read more about the study on the accuracy of different COVID-19 testing kits.

But it is important to remember that tests don’t work as well in the real world. No viral test is 100% accurate. In real-world use, the viral test for COVID-19 is not 100% ‘sensitive’ (meaning able to correctly identify people with the disease all of the time). This means that if 100 people who have the disease are tested – some will have a negative result (i.e. a false negative result).

Reasons for a false negative test result could be because: 

• the sample was taken at the wrong time (too early or too late) 
• the swab did not pick up any pieces of the virus, or 
• the sample of mucus (or liquid from the lungs) wasn’t big enough. 

This means that it is very important to isolate yourself if a health professional asks you to, even if your test result is negative.

The viral test for COVID-19 is much better at correctly identifying people who don’t have COVID-19 (this is known as a higher ‘specificity’). We expect very few (if any) false positive test results (a false positive being a positive test result for someone who does not have the disease).

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What the test results can and cannot tell us

Even when we take the uncertainties of testing into account, the results can tell us a few things.

The following statement is inaccurate - SMR

A positive test tells us that a person either has COVID-19 (whether they have symptoms, or not) or has had COVID-19 recently. We may not be able to distinguish whether the person is currently infectious or not so we will take a precautionary approach. 

A positive test cannot tell us:

• if the person is currently infectious
• how ill the person is likely to become.

A negative test can tell us:

• the person was unlikely to be infectious at the time of the test.

A negative test cannot tell us:

• if the person was exposed to the virus or not
• if they are in the early stages of incubating the disease
• if they caught COVID-19 in the past 
• if they were infectious in the past
• that they will not get COVID-19 in the future.

Note: if a person has a negative test result and they are at a higher risk of having COVID-19, they may be tested again.

Here is a coherent answer.