Wednesday, 17 February 2021

Test test test

My column over at Newsroom this week points out the fairly obvious.

The government can add daily saliva testing for everyone at the border to the existing testing regimen. 

If daily testing winds up proving the swab tests to be redundant, ditch the swab tests when we find that out. 

If it turns out they're both useful, keep both.

And in the very unlikely chance that the saliva tests wind up being redundant, they won't have cost much.

From the column:

Saliva-based PCR testing is a game-changer. It is at least as accurate as the swab tests currently used, but has several advantages over the swab test.

Because it relies only on saliva collection, it does not need scarce medical professionals to gather the samples. Availability of nursing staff is a substantial constraint in the system – and especially since the government shifted border nurses back onto the lower pay rates available through the district health boards.

Swab-testing can make people sneeze in reaction to having a swab stuck up their nose. Saliva testing does not come with that risk. Sneezes are far riskier than some drool on a disposable spoon.

And, finally, because providing the sample is far less inconvenient and invasive for the person being tested, and because it comes at only a fraction of the cost of the swab tests, it is rather more feasible to require it as part of a daily testing regimen.

Suppose the tests cost on the order of $35/pop (the Milne article doesn't say, but notes that large-scale runs would be less than the $40-$50 range advertised for smaller runs. And suppose there are 5k people in MIQ and 10k people in the border system. 15,000 * $35 = about half a million a day in test costs. So about fifteen million a month. 

If we run it and find, after a month, it was useless, we might have wasted twenty million. Less than a tenth of what the government decided to throw at some stupid boat race in Auckland. 

If we run it and find it to be useful, we get to spend maybe twenty million a month for substantial reductions in the risk of the virus getting out into the community and future lockdowns. 

And, just as obviously, daily testing gives us way more information about what the heck is going on. Are the cases that are currently found at Day 12 ones that just took a long time to incubate, or are they cases that were transmitted within MIQ? If we knew what was going on at every day along the way, we'd see it right? The PCR tests would make it way less likely that people could transmit within MIQ. They'd reduce the inherent riskiness of potentially infectious people sitting in hotel rooms not designed as quarantine facilities and spreading infection through ventilation systems. Right now, somebody could be infectious and asymptomatic in MIQ for days and days before being caught. Daily testing would fix that. 

My working hypothesis has been that MoH is just a wall of "Computer Says No" because the whole system's held together with bailer wire and they know they can't trust themselves to try to adjust anything. But some moves reduce the riskiness of the whole shambles. Daily testing in MIQ makes the whole thing less risky. 

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