A certain slackness: coronavirus statistics and contact tracing.

BBC were very guarded about "a primary school", but the name came out on the ITV news, which made it very strange listening to the BBC announcer saying the school had not been identified! The ITV report noted that:

Some parents at St Michael's School in Jersey have told ITV News they had to collect their children after a student in their child's class tested positive for Covid-19. Track and Trace say those in the same class will have to self-isolate for two weeks or can undergo tests on Day 0, Day 5 and Day 8. It is not yet clear how the child contracted Covid-19.

We hear of the wonders of track and trace, but "It is not yet clear how the child contracted Covid-19" should strike alarm bells, because if it was working, we should have some idea where the child contracted it from.

What we still don't know:

Where the infection came from?

How did the testing come about?

Was it symptomatic?

Has anyone who might have been a carrier been abroad?

The last is significant, as the story also broke of a Jersey Reds player coming to Jersey and showing negative on the first test, but positive on the second. Given that by and large at least half the cases have been asymptomatic, how much coronavirus has invisibly made its way back into the community.

The recent statistics show that: Twenty-three of the thirty (twenty-two arrivals and one direct contact) tested positive on Day 0. Six tested positive on Day 5 and one on Day 8.From that we may conclude that those 7 tested negative on Day 0. While the numbers have been small, the months of just giving a single test to locations designated green also gives credence to the idea that some virus is still within the community.

That brings me to my next gripe. Most travel cases enter the statistics which differentiate between hospital - 1 case, care homes - 0 cases, and community, 60 cases.

I want to know which of those 60 relate to travel, which are contacts of those travellers, and which are outside that. That they are "in the community" tells me precious little. I'd like a figure - which Guernsey consistently provided - on cases where no route of transmission can be identified. 

We know that of the 30 recent cases, 25 new cases have been identified in Jersey through inbound travel and 5 were identified through contact tracing. But how about past jumps, especially when they appear for workforce screening?

The recent figures obviously do not account for the pupil at the school, so how reliable are these figures? As far as the ITV report notes, they are not a know contact, but are "in the community".

It would also be useful to know more about the contact tracing. Were the 5 case family members, or were they people met when the travellers were out and about in the community? This all helps us assess risk far better and it's just not there.

And just a note that contact tracing in restaurants and cafes is still flawed - it is not mandatory for the customer to provide details. And there are still beach cafes not doing it, despite the fact that they may be close to hotels. The late introduction of mandatory isolation while waiting for a first test shows the same kind of slackness.

Lastly, I see the number of symptomatic cases has fallen. I do hope that the asymptomatic cases will be properly reclassified if they turn out to be presymptomatic, as that certainly wasn't the case back in the early days of reporting.

References
https://www.itv.com/news/channel/2020-10-12/jersey-primary-school-class-sent-home-after-child-tests-positive-for-covid-19