Test, track and trace… How do modern detectives use technology to supplement shoe leather?

In early February, a person carrying the corona virus went home from Singapore to Hove via a ski chalet in France. When a test found them to be positive for the virus, officials from Public Health England (PHE) went to Hove and started the process of tracking where they had been and with whom they had spent time since coming back to Britain.  They then traced those they had come into close contact with and may therefore have infected.

Because I knew about this process before I was not surprised at how effectively this was done. But my friend Peter Kyle, the local MP for Hove, had never seen ‘test, track and trace’ in action before and was impressed. In no time at all 200 PHE staff were involved in tracking and tracing where the infected person had been. (Remember this. In February it took 200 staff for one person).

So effective was this process at the time that all the contacts were traced and the only ones infected had been in the same French chalet with the person from Singapore. Not one of them infected anybody else – and this was at a time when the average spread was 1:7.

At some stage in the near future, as lockdown diminishes, we will all be looking to test, track and trace as being a part of the next phase of all of our lives. Just as in recent weeks we have all come to know much more about ventilators, so will we all get to know more about test, track and trace.

The first thing to say here is that there is no getting away from the fact that the nation will have to have both a much higher capacity to test and a much better distributed system of applying those tests to people. Without that everything else falls.

Tracking is a straightforward walk-through of all the locations an infected person has visited. In a modern, open society this track will take us to several very different locations. When I return from holiday, I may go to a couple of shops for food, a café for a coffee, perhaps even a pub for a drink, and then a restaurant.

Within a few hours my track will have covered many different places.

I hope some of you are fans of detective stories because the analogy between detective work and this public health activity is very relevant to this post. Whenever I watch Lewis or Vera they track backwards – without much help from the corpse – where the victim had been in their last day. So tracking is important and achievable.

But tracing is more complex. Tracers follow the track. Take the example of my coming back from holiday. Tracers will have to visit 2 shops, a café, pub and restaurant. In this modern England they will be assisted by more CCTV than any other western country. The tracers can obtain data from the shops, café, restaurant and pub and see who I was close to for any length of time. Did I pay by card or by cash? Did I sit away from people at other tables or up at the bar? Some of this is in my memory.  A lot of this is on record.

The tracers may then decide that since I was standing at the bar of the pub – they only have to trace bar staff that spent some time talking to me. They then need to find them and ask them to self-isolate. One person could be in contact with many people but only a few of them may be close enough to have to self-isolate for 7 days.

All of this, like all police work, is filed and information logged. As work continues with a specific virus more knowledge can be deployed to work with specific tracing. And the odds of our having infected a, b and c but not x, y and z become better understood.

Within the public health community, this is called ‘shoe leather’ public health. Because that is what it takes. Private detectives are sometimes called called ‘gumshoes’ and the police refer to this as ‘legwork’. It’s the basis of all three professions.

But all of this has now been supplemented by modern technology. Watch a modern detective at work and they will track the movements of suspects and victims alike through phone records of which masts it accessed. This does not do away with legwork, but it does supplement it.

The same will be true of shoe leather public health. Mobile phone records will help to develop the track and some of the tracing.

We now know that this will be supplemented by an NHS ‘app’ which, if enough people download it, will keep track of movements. There will be a passionate debate between those who feel this will encroach on their civil liberties and those who feel that such a loss will be worth it to end the lockdown. But one way or another technology will complement shoe leather.

Regular readers will already be aware that one of the main problems with our government’s policy and practice in dealing with the coronavirus has been an over-centralisation pf their activities. The same problem could arise with test track and trace. Tracking infected people through streets, shops and local workplaces that you know is much more effective that doing so through areas that you don’t know. So local knowledge and local organisation will matter here. PHE is a national organisation but it works with local government who will be much better placed to organise this.

Major local authorities don’t just have public health responsibilities. They also have environmental health officers who trace outbreaks of illnesses caused by the sale of food or meals in restaurants. If you get bad food poisoning someone will track everything you have eaten and trace what happened. They will talk to the place that gave you the illness and trace others who may also have caught something.

This is organised locally – because local knowledge matters. We have some expertise of doing this across the country in every major local authority and we must build on this.

We will need many more people to do this. The German government are appointing and training up 5 people per 20,000 of the population.  That’s 250 people per million – for 50 million that’s 12,500. Looking at the situation in England at the moment it would be remarkable if we had 5,000.

Given that we will need all these people to be ready in a few weeks from now it would be a good idea to select, appoint and train them NOW.

Wouldn’t it be a pity if, in 2 months’ time, we were to hear that the government was working night and day, straining every sinew, etc. etc. to get 12,500 people appointed and trained? Especially when we have just learned (with PPE) what happens if you don’t start early.

Two things to take away from all this:

  • However and whenever we come out of lockdown we will need testing tracking and tracing.
  • It would be a good idea to start getting the tests and the staff together now, rather than wait until we need them.

The days we lose now are gone for ever.