Adam Briggs Profile picture
16 Oct, 21 tweets, 13 min read
Wk 19 Test & Trace. 01/10/20 – 07/10/20.

Cases up.
Positivity up.
More cases reached but fewer contacts.
And it's taking longer.

Plus this week has 11k extra cases because of the delayed transfer of 15.8k cases…

Summary in pics, detail in thread 👇

Particularly pillar 2 (community)
Cases⬆️69% from 47,656 to 80,485; positivity⬆️to 7.7% from 5.3%

For Pillar 1 (hospitals/outbreaks)
Cases⬆️32% from 7,119 to 9,389. Positivity now 2.5% from 1.9%

And new for TT, number of individuals tested each week rising wk on wk.
By age – as with last week, cases in 10-29 y/o STILL rising fast without big changes in numbers of tests done. This is reflected in the PHE surveillance positivity data by age.

But ONS breaks this down into much more useful age categories, showing cases now starting to rise in 11-16y/os, so not just 17y/o+

(and a brief aside on testing, good to see positivity rate now being published by TT, but would be even more helpful if this distinguished between symptomatic and asymptompatic/routine testing as frequently argued by @fascinatorfun)
In terms of T&T performance, it’s remains disappointing.

First, a whopping 87,918 cases transferred – includes 11k from the 15.8k cases that were missed between 25/9 & 02/10, transferred in bulk on 3/10.

Despite this, the percentage of cases reached was up from 75% to 77%.
And the number providing details of close contacts, also at another all time high of 85%
This mean a lot of contacts. 216,627, to be exact.

And this is where we see problems.
The time taken to reach these cases has fallen for four consecutive weeks and is now just 56% compared with 77% in the first week of Sept.
This has massive implications for local contact tracing systems, now operating in around half of local councils across the country.

They generally take cases that haven’t been reached within 24 hrs.
This means that this drop in TT performance means not only are local gov receiving more cases to manage (without more ££) due to rising case rates, but also because a smaller proportion are being reaching by TT in a reasonable time.

More detail here:
It also begs the question, what proportion of the 77% reached are by TT & what are local gov systems?

This would be so useful to understand the impact of local systems, especially given talk of the widening role/responsibilities of local gov in TT as local case rates increase.
Of the 216,627 close contacts, there are big drops in the numbers of contacts identified per case.
Down to 2.9 per case for non-complex cases (3.4 wk before)

And 14.8 per case for complex cases (outbreaks/high risk settings) down from 21.7 last wk.
Could be 11k delayed cases not remembering their contacts, or it may be a sign of the impact of growing social restrictions.
Or may be something else (like people not wanting to report contacts - but I think unlikely given proportion of cases reporting contacts is increasing).

The rising proportion of close contacts that are same household may support the possibilities it reflects social restrictions.
Unfortunately the percentage of contacts reached has also dropped again, now at just 58% down from 64% two week ago.
And the proportion of close contacts reached within 24 hours of either the contact or the case first being identified is now at an all-time low of 61% and 39% respectively.
Finally – a functional TT system is so so important.

And if our current one can be improved by working more closely with local gov then that's great & we should do it. But this has to be supported by the necessary resources for already madly stretched local teams.
And finally two - we've started a new TT tracker summarising a few key points each week/every other week. Do let us know what you think.…

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More from @ADMBriggs

16 Oct
Short thread on today's latest @ONS COVID Survey release for 02/10 to 08/10

The number of community cases is really rocketing - now estimated at 27,900 cases/day in England.…
This is about double what's coming through on Test and Trace data for the same time. And note that ONS doesn't include care homes, hospitals OR INSTITUTIONS - this means Uni halls of residences and colleges where we know there are significant outbreaks.
As with national testing data (as reported in PHE surveillance report), huge geographic variation with NE, NW, Yorkshire/Humber still massively more cases than elsewhere.

BUT cases may be plateauing in the north, although not in midlands/London.
Read 7 tweets
15 Oct
National Flu and COVID surveillance report now out, reporting 5-11th Oct.

Short(ish) summary…
Cases and positivity (to 7.8% in pillar 2 and 2.7% in pillar 1).

Although not rising as quickly this week as in previous weeks, it remains hard to interpret what it means for community prevalence because it's still unclear what testing access issues remain across the country.
Case numbers and rates still dominated by 10-29y/o age gp, but worth looking at rising case rates in all age gps, including 0-4 and 5-9y/o
Read 16 tweets
12 Oct
Local contact tracing is where local authorities set up local teams to contact cases that the national team is unable to reach within 24hrs.

They're seen as part of the solution to rising case numbers in England.
And with good reason. Early data from places like Blackburn with Darwen @BWDDPH suggest that they're able to reach up to 9 out of 10 cases that couldn't be contacted by the national team.…
Some of the cases that that national team miss don't want to be reached and won't ever engage.

Some just missed the call or didn't recognise the number.

And others are likely to be more vulnerable, socially isolated, digitally deprived, transient, or economically worse off.
Read 22 tweets
8 Oct
Week 18 Test & Trace data summary. 24/09/20 – 30/09/20.
And some of today's PHE surveillance rpt as well.

Not so good.

Cases, admissions, deaths up.

TT performance continues to worsen, not to mention Excelgate.

Summary in picture, detail in thread 👇…
Cases in pillar 1 up 13% from 5,171 to 5,855 (NHS/PHE labs – outbreaks/hospital)
Cases in pillar 2 up 64% from 27,761 to 45,620 (community)

Number of new people tested – no change. This seems to have plateaued (see later in thread about this and positivity rates)
By age – rises in all age groups but note BIG jump in cases among 10-19yr olds.

This is alongside no change in number of new people age 10-19 tested.
Read 32 tweets
1 Oct
Week 17 Test & Trace data summary. 17/09/20 – 23/09/20.

Not a pretty picture.

Cases ⬆️61%.
Tests ↔️
Test positivity rate ++⬆️from 3.3% to 5.3% (+ some useful detail by age)

Test and Trace performance worse.…

Summary in picture, detail in thread 👇
Despite no change in number of tests,

- cases in pillar 1 ⬆️34% from 3,653 to 4,898 (NHS/PHE labs – outbreaks/hospital)
- cases in pillar 2 ⬆️67% from 15,853 to 26,475 (community)

Means positivity for pillar 2 ⬆️from 3.3% to 6.7%
And pillar 1 ⬆️from 1.8% to 2.5%
And like @PHE_uk surveillance, they now give data by age

Case numbers still dominated by 20-29/yr olds, but growth in cases across all ages (except 90+)

And there are big differences by age, steep rises across all age gps b/w 20-70yrs
0-19yrs much less change in positivity rate
Read 24 tweets
1 Oct
REACT-1 study results - data to 26th Sept. Some context.

1 in 200 in Eng infected (far more than ONS survey to 19th Sept, which estimates 1 in 500)

R number lower-now 1.1, doubling time longer-now 10.6 days, BUT rise in number infected is substantial.…
Prevalence highest in 18-24y/o (same as ONS)
BUT 7 fold increase in rate over 65y/o.

And BIG regional variation.

This is similar to ONS survey results.
So encouraging that R number falling, BUT this will be different in different parts of the country.

Rise in infection rates in older people.

Rates 2x as high in Black & Asian ethnicity vs White

And now 0.55% of population infected=approx 411,000 people (ONS estimate 104,000).
Read 5 tweets

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