Thread by @ADMBriggs

Week 11 NHS Test and Trace data summary. 06/8/20 to 12/08/20.

This week seems really important and raises lots of questions.

BIG increase in cases, and big drops in numbers of contacts traced.

Summary in picture, detail in thread 👇

gov.uk/government/pub…

KEY POINTS

27% INCREASE in cases compared to week 10

Includes:
34% ⬆️pillar 1 (hospital cases/care home outbreaks)
26% ⬆️pillar 2 (community cases)

AND
2% ⬇️testing (5% ⬇️pillar 1, 0.4% ⬇️pillar 2)

This may mean higher case rates in the community and in hospitals/care homes

The wk on wk ⬆️in cases last week was just 4%, potentially driven by more testing.

This doesn’t seem to be the case here. Pillar 1 %age positive⬆️from 0.41% to 0.58%, & pillar 2 from 1.55% to 1.95% (highest since wk4)

Epi curve seems back on track for a possible 2nd peak, BUT

This is not mirrored in @ONS COVID survey data which suggests that community infection rates are levelling off.

ons.gov.uk/peoplepopulati…

And looking at overall UK cases from gov.uk, it mirrors T&T through to 12/08/20 and then seems to be leveling off again. And as with last week, still no sign of increased hospital admissions or deaths.

coronavirus.data.gov.uk/healthcare

What’s going on?

First - why drop in testing after previous wk on wk increases
-Fewer non-COVID bugs causing similar symptoms?
-People on holiday?
-Chance?
-Something else?

Second – why increase in positive test rates and numbers of cases (esp pillar 1)?
-Higher community and care home case rates?
-More outbreaks?
-More unwell people? (not reflected in gov.uk data)
-More targeted testing? Possibly.

Third – why not reflected in hospital admissions/deaths?
-younger/less vulnerable people affected?
-Lag time between infection, hospitalisation & death (10-14 days)?

Need data on breakdown by age, setting, outbreak type to start getting to bottom of this.

And please read this thread on cases in Florida – it is so important to continue to track this in detail as cases rise and be prepared to act early. Young people can so easily infect those who are much more vulnerable.

https://twitter.com/firefoxx66/status/1296080742607355904?s=20

Back to T&T.
ONS still says around 3,800 cases per day (wk ending 9th August). Testing finding around 950/day. Smaller difference than last week but still a big gap, even if assume 2/3 cases are asymptomatic.

Basically, there are LOTS of unanswered questions here. Rising cases, falling test numbers, ONS/hospitalisations data suggesting things are static.

Now wait to see what’s happening with T&T (it’s a real eye-opener).

(here’s the graph with major policy details.)

First, the numbers transferred is 4,803 of 6,616 positive cases – difference=1,813. >25% of cases. This is HUGE. Since wk4 it’s never been >370.

Apparently 681 cases with tests b/w 6/8 & 12/8 didn’t get uploaded until 13/8
Remaining 1,213 apparently explained by reasons in pic

Something is clearly very off here. And that’s a lot of delayed contact tracing.

Proportion of people reached has dropped slightly from 80% to 79%.

And third wk in a row of slight falls in numbers of people providing details of contacts.

I find it hard to believe this is because fewer people have contacts, but could be wrong.

There was 3% fall in number of cases transferred to T&T from wk 10, but a 19% fall in the number of contacts identified. From 20,959 to 16,897 contacts.

Falls are across both complex and non complex cases

The fall in contacts is due to both fewer cases transferred to T&T, and fewer contacts per case.

Overall contacts/case dropped from 5.2 to 4.5.
Due to a small drop in contacts per case for non complex (3.5 to 3.2), & big drop for complex (27 to 19 contacts/case). This may be due to better isolation/infection control processes (but contacts/complex case varies a lot wk on wk)

And then more bad news, % contacts reached has dropped from 74% to 71% overall, driven by a fall from 61% to 59% for non complex contacts (complex remains same at 95%)

Plus big geographical variation in % contacts reached that may widen inequalities given what looks to be a N/S divide.
Is this due to problems with contact data, willingness to engage, structural barriers?

Seems to be less of a variation for contacting cases. Need detail on contacts/case by region to understand better what’s going on.

Test time from request to result has continued to fall (perhaps driven by the 681 cases not initially transferred), for T&T to reach case has stayed the same, and time then to reach contacts has lengthened. Again, it’s a disappointing pattern.

Last week I was quite positive about it all. I’m far less so now. Not only a large jump in cases (need to wait to see how that pans out), but also some disappointing T&T performance data.

And lots of unanswered questions that need teasing out.

All published in the week we hear about @PHE_uk being scrapped.

An alarming decision that's looking increasingly risky.

As ever, thoughts with PHE colleagues as they continue to work round the clock to keep us safe.

Wk 11 here. @felly500 @trishgreenhalgh @deb_cohen @martinmckee @carolecadwalla @mgtmccartney @ADPHUK @Jeanelleuk @hughalderwick @profchrisham @petermbenglish @HPIAndyCowper @Davewwest @ShaunLintern @HSJEditor @KateAlvanley @IndependentSage @Billy_Palmer_ @nedwards_1 @chrischirp

@PaulNuki, I’m sure you’ve seen but just in case, you might be interested in this week’s data too.