Adam Briggs Profile picture
22 Apr, 18 tweets, 12 min read
Updated our T&T performance tracker, covers 8-14th April.

Key points
- lots of changes to LFD use, with differences across the country
- despite falling cases, end-to-end journey time from symptoms to reaching contacts increasing

Detail in 🧵…
After a dip over the Easter bank holiday w/e, number of people tested increased by 15% to 4.4m

although this is still some way off the peak of 6.2m four weeks earlier
The changes have been mainly due to variations in use of rapid lateral flow devices (LFDs).

These have been rolled out by the government for people without symptoms over recent months and are now available to everyone in England.
The drop in LFD use in the last week of March/first week of April (down from 7.1m tests a week to just 4.0m) was mainly from fewer tests from secondary schools and colleges.

The fall coincided with the shift to testing at home, and start of the Easter hols.
In the most recent week, LFD use was up by 750k.

Only around a fifth of this rise is explained by school testing, with the rest coming other government testing schemes – in particular LFDs being made available to everyone from 9 April 2021.
There are still important differences by region.

The highest LFD use is in the East of England with 12,500 tests per 100,000, compared to just 5,200 per 100,000 in London.
This will partly be explained by the different dates that schools returned across the country, but also due to differences in factors such as employment, access, and willingness to engage with the scheme.

Important to monitor moving forward now everyone has access to LFDs.
Despite the 15% increase in the number of people being tested, case numbers still fell by 9%.

Whilst overall T&T performance remains broadly unchanged, there is an increasing trend in the time taken to reach contacts from when a case is first passed to the system.
Perhaps surprisingly, week on week fall in the percentage of cases providing details of contacts, but overall contacts per case rising.

Now 4.2 contacts per case, up from just 2 in mid-Jan.
Big drops in the percentage of contacts from the same households.

The fall would be expected, but the extend of the drop is perhaps a little surprising.
It's this drop in % of contacts from the same household that explains the slight fall in success rates of reaching contacts overall.

In fact, success rates of reaching HH contacts is the same as previous wks (97%), and slightly improving for non HH contacts (now 78%).
As more contacts are identified per case, and more of these are from outside of the case’s household, the median time for contacts to be reached from when a case first developed symptoms is now 97 hours.

Up from just 79 hours two weeks previously.
Part of the issue seems to be with it taking longer to reach cases.

The % cases reached within 24hrs has dropped, whereas test turnaround time is generally unchanged, as has % of contacts reached within 24hrs of contacts identified.
As society continues to open up, any additional time gives more opportunity for the virus to spread, so it’s crucial this trend doesn’t continue.

And as ever, these numbers don’t tell us about who doesn’t get tested and who struggles to adhere to isolation.
As the number of cases in the community falls and social mixing increases, it becomes ever more important that any cases that do occur are identified and managed as quickly as possible before the virus has the chance to spread.
And here's the overall summary slide.

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More from @ADMBriggs

22 Apr
PHE's surveillance report for 12th to 18th April now out. 🧵

Second week of school holidays for most, but some schools will have gone back.

- case numbers down & vaccination up
- persistent inequalities by geography, ethnicity, & deprivation…
Case rates & positivity continue to fall across the age groups with no clear sign of pre-Easter rise in school-age cases leading to more infection in older ages.

Highest in 10-19y/o (42 per 100,000) and lowest among 70-79y/o at just 7.2/100,000.

A pattern matched by ONS survey
Case rates also falling across all the regions, with slightly higher rates in Yorkshire and Humber (45 cases per 100,000 compared with just 14/100,000 in the SW).

Again not dissimilar to ONS and good to see case rates come down (next ONS update due tomorrow)
Read 18 tweets
19 Apr
Having now worked it's way through the @Telegraph system: with @louisemarsha11, our take on the plans for replacing Public Health England. 🧵

tl,dr: we need a more, not less, joined up system if we're serious about health & inequalities

No £-wall🔓…
PHE is being split into the UK Health Security Agency (UKHSA which also includes Test&Trace) - focusing on external threats like pandemics

and the Office for Health Promotion - focusing on health improvement and inequalities, such as obesity and tobacco.…
As we wrote at the time, it's a risky business reorganising public health in the middle of a pandemic.…
Read 25 tweets
8 Apr
This week's Test & Trace data - for 25th to 31st March (around the last week of school before holidays)

- LFD tests down
- big variations in LFD use across the country
- and increase contacts per case.…
The number of people tested week on week has fallen for the past two weeks, down to 4.8m from a high of 6.2m.
The fall is due to reductions in LFD use - down 23% to 5.5m.
Read 25 tweets
8 Apr
This week's @PHE_uk COVID surveillance report, 29th March to 4th April (incl. start of the school hols). 🧵

⬇️ case rates, partly from fewer 10-19y/o LFDs with no clear sign yet of schools leading to ⬆️cases in older ages

+ important variation by region…
Further drop in cases in the most recent week following a bit of a flattening off in previous weeks - with some of this due to school holidays and fewer LFD tests.

Worth noting that for March, both REACT and ONS surveys suggest that case rates are generally static.
Big drop in LFD use, which is mainly due to a drop in test use by secondary schools (see T&T data).

The drop off has accelerated with the school holidays, but the move from testing in school to at home may have contributed over the past few weeks.
Read 19 tweets
8 Apr
Latest update from REACT-1.

Looks 11-30 March (schools fully reopened on 8th March).

- Suggests infection rates fell by around 60% between Feb and March to 0.2%
- Big differences by age, region, and deprivation
- R now estimated at approx 1.…
Falls across all regions but highest rates still in NE, NW, and Yorkshire and Humber (round 9 is swabs from 4th-23rd Feb, round 10 is 11th-30th March)

Includes 12% probability R>1 for Y&H between two rounds. <1% in all other regions.

This is consistent with ONS survey data.
Highest infection rates among 5-12y/o (as does ONS), but REACT suggests lower infection rates among school age children than ONS does.
Read 4 tweets
1 Apr
PHE latest COVID surveillance report now out, as is ONS.

Covers 22nd-28th March 🧵

-cases down all ages except 10-19yrs.
-Significant geographical variation.
-Vax still motoring.
Fall in case rates in all age gps (incl 5-9y/o) *except* for 10-19y/o where they've increased by 7% to 110 cases/100,000.

Lowest cases rates are among 70-79y/o at just 11/100,000, and generally there's a step decrease in case rates for ages 60yrs+ compared to those <60yrs.
And among 10-19y/o, case rates seem to be rising mainly among 10-16y/os.
Read 27 tweets

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