The huge problem with Track, Trace, Protect in Wales

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The Track, Trace, Protect (TTP) program in Wales is under monstrous amounts of pressure at the moment.

With over a thousand cases reported every day the teams are facing an immense challenge to trace people and their contacts.

In the summer, TTP was hailed as the long term way to keep the virus under control. Contact people who have the virus, find out who they have been in contact with, get those people to isolate.

In those warmer months the TTP scheme was a real sucess. Outbreaks in Merthyr, Wrexham and Anglesey were nipped in the bud and never spread into more wider community transmission. Not only did it help contain those outbreaks, the information gave experts and policymakers real time data on how the virus was moving and what the riskiest settings were.

But then winter happened.

Instead of dealing with 20 cases and associated contacts a day, they are now facing 8,000.

So what is going on with Wales’ TTP system? We have gone through the data to assess the pressure the system is facing.

The scale of the challenge

The table below shows how the demands on TTP of have skyrocketed since the start of autumn.

For the entire month of July, tracers had to contact 451 combined positive cases and their contacts. On December 28 alone they had to contact 8,266.

We can also see how some areas have been under more sustained pressure for longer than others:

How long is it taking to track contacts?

Health Minister Vaughan Gething has taken every available opportunity to extol the virtues of the TTP system.

On the face of it the figures for TTP are impressive. Let’s take the last week of December (Dec 27 – Jan 2) as an example:

A whopping 13,910 positive cases were eligible for follow-up and of them, 12,827 (92%) were reached and asked to provide details of their recent contacts

Of the 31,205 close contacts that were eligible for follow-up, 25,760 (83%) were successfully contacted and advised accordingly, or had their case otherwise resolved. This is a drop from the summer, however. If you include all the data from June 21 98% of positive cases were reached and 91% of contacts. However, with the enormous case load they now have, this is to be expected.

So there is clearly no huge issues around actually contacting people. But what about how long it is taking to make that contact?

If we look at that same December 27 – January 2 time period we can see.

Of the positive cases, 13,910 cases in that period, 69% of them were reached within 24 hours of referral to the contact tracing system. A total of 87% were reached in 48 hours.

In terms of close contacts, of the 31,205 close contacts, 66% were reached within 24 hours of being identified by a positive case with 75% reached in 48 hours.

However, these figures for tracing contacts plummet if, instead of measuring the length of time from when the postive case identified them, we measure it from the time the positive case first appeared on the system.

Find out about coronavirus cases in your area:

If we measure the time taken to find contacts from when the positive case was first identified, only 32% of close contacts were reached in 24 hours with that rising to 52% in 48 hours.

So what does this actually mean? Well, if we take that week as an example we can say the following things:

  • About half of people who have contact with a positive case don’t hear from tracers within two days of TTP being aware of a case.
  • Only 10,000 of the 32,000 close contacts that week were alerted by TTP within 24 hours of the positive case being referred to TTP.
  • Just under a third of positive cases don’t hear from contact tracers within 24 hours.

Before we look at what that means for the spread of the virus in Wales, it is worth asking if that week is reflective of the typical performance of TTP?

We opted to use that week as an example because it is the most up-to-date data available. The week before the figures were far lower with just 17% of close contacts reached within 24 hours of the positive case that identified them being referred to the contact tracing system. However, this was over Christmas, so may not be reflective of usual performance.

So what does this mean for the spread of the virus in Wales?

To understand what this all means it is worth creating a timeline for how people are tracked in Wales to understand why it is so hard to get the virus.

To do this, let’s imagine a person called Dave and assume they follow the guidance.

Imagine Dave got symptoms on January 1 and immediately isolates. He books a test and has one the next day (there is usually space within 24 hours but back in the autumn there were real issues getting quick tests). By the time that result comes back positive (which is usually within 72 hours but was often far longer in the autumn) he then awaits a call from contact tracers.

As we know, he has an 87% chance of getting that call within 48 hours but it may be longer.

The contact tracers will then ask for his close contacts for the two days before he started showing symptoms.

A contact means:

  • someone within 1 metre of them with whom they have had a face-to-face-conversation, had skin-to-skin physical contact, have coughed on, or been in other forms of contact within 1 metre or 1 minute or longer
  • someone within 2 metres of them for more than 15 minutes
  • someone they have travelled in a vehicle with – or has been seated near them on public transport.

We then know that these contacts will have a 50/50 chance of being contacted within two days of him testing positive.

So how long could it take for a contact of Dave to be told to isolate?

Well let’s add it up:

  • Two days since they met.
  • One day to get a test.
  • Three days for a result.
  • Two days for tracers to speak to the positive test and contact you (though about 50/50 to be longer than that)

All told you are looking at eight days from that point of contact before the contact tracers can get to you. By that point you are nearly at the end of the 10 day isolation period you would have to do anyway. And this is if you are lucky with getting a test, having it come back etc.

So is TTP no longer working?

Well the first thing to stress is that this is not a criticism of the workers within the TTP system.

They are up against an absolute avalanche of work with limited resources. They can only react as fast as the testing allows. And even then they are totally reliant on people actually picking up the phone and providing reliable and timely contact details.

But the question of whether TTP is fufilling its purpose of reducing cases depends on how you look at things. It would be fair to argue that, given we are all in a level four lockdown with the virus still growing in parts of Wales, that TTP is not working at all.

However, we need to consider what a working TTP system looks like.

In a powerful article in Nature the countries with the most effective contact tracing systems were identified including South Korea, Vietnam, Japan and Taiwan.

There are a wide range of differences in how these countries have operated compared to the struggling systems in the UK including:

  • More tracers
  • Better of use of tech
  • Different parameters for what constitutes a contact (Taiwan has an average of 17 per case whereas the UK average is two)
  • Behaviour of citizens

But perhaps one of the biggest differences is the decisions of these countries to lockdown hard and lockdown early. At the first smell of a rise in cases countries where tracing has worked will lockdown early. This means that they never get to the totally unmanageable position that Wales’ contact tracers are in now.

Politicians regularly praise the virtues of TTP. But while acknowledging that staff are working as hard as they can, there are inherent limitations in what TTP can possibly do in Wales, given the time scales they are working to. The World Health Organisation defines a successful contact-tracing system as one where a country can trace and quarantine 80% of close contacts within three days.

Saying “90% of contacts reached” means very little from a virus containment point of view if it is nine days after they have met.



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