Friday 18 February 2022

Pooled failure

I called this one in January, and I think I was the first one in NZ to write about it.

The country’s Covid testing system is likely to fall apart, quickly, when case numbers rise.

Testing labs can bundle five to ten samples together for testing. If none are positive, all is fine.

If the pooled sample is positive, individual samples need separate re-testing. When positivity rates are low, the system works well. But when positivity rates are high, pooled sampling stops working. Testing capacity drops to a small fraction of what it had been, just when it is most needed.

Headline figures on testing capacity may be more than a little optimistic. Contracting now for greater capacity, focusing on the saliva-based PCR testing (which identifies genetic material from the virus) that catches Omicron cases earlier, matters.

Today's NZ Herald:

Earlier this week, director general of health Dr Ashley Bloomfield said the seven-day testing average was sitting at around 22,000 or 23,000 per day.

Bloomfield said daily PCR test capacity could be surged up to 60,000 to 70,000 – but also noted that, in the outbreak's centre of Auckland, the present capacity was only 20,000.

Even with local positivity rates of 3 to 5 per cent, Auckland labs weren't able to pool samples, which reduced capacity.

Without being able to pool samples, Bloomfield said national capacity would be around 30,000 samples per day.

It wasn't clear what extra impact a just-announced strike of 10,000 DHB staff - laboratory workers among them - would have.

Prognostication's a curse. You can see the train wreck coming, you can shout about it, but you just can't convince an utterly useless government to do a damned thing about it. 

Bit of a shame that the Herald piece didn't mention that all of this was entirely predictable, was predicted, and could have been avoided by contracting for more capacity with a testing lab that wasn't running pooled samples. 

If it comes to a strike, Bloomfield and Hipkins will do the predictable thing. 

They'll throw their hands up about how none of it is their fault. They'll forget that they could have contracted with more than one supplier for testing. Instead of running everything through a single point of failure, APHG, they could have contracted with Rako, which uses different labs.

At what point is MoH criminally negligent?

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