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A comment from Professor Sheila Bird on latest NHS Test and Trace stats and booster vaccine stats.
Prof Sheila Bird, Formerly Programme Leader, MRC Biostatistics Unit, University of Cambridge, said:
On latest NHS Test and Trace stats:
“The number of antigen lateral flow tests registered by NHS primary care staff was 119,389 in the week of 14 to 20 January 2021 when 3 per 1000 were LFT-positive (362) to a maximum of 169,977 in the week of 28 January to 3 February 2021 when 1.6 per 1000 tests were positive (277).
“By September 2021, the number of LFTs registered per week by NHS primary care staff had reduced to 95,340 (nearest 10) but the positive rate had increased to 3.9 per 1000 (1501/381,356); and in October 2021 was 4.1 per 1000 (1502/362,999). The monitoring statistics do not tell us how many LFTs should be registered per week by NHS primary care staff if compliance was, say, 80% with LFT-policy. Notice, however, more than 40% reduction from the maximum weekly number of tests registered; but 340 to 400 positive tests per week in each of the past 8 weeks.
“About three-quarters of self-report home-test LFT positives can be matched to PCR-adjudications. The table below covers the period before/after PCR-testing was suspended at a laboratory in Wolverhampton. On the basis around 40,000 PCR-confirmations per week and PCR-negative rate of 8%, standard error for comparing between two weeks would be roughly 0.2%. Even without the IMMENSA hiatus, the data appear to be more noisy so that there are other factors in play, not least changing prevalence of SARS-CoV-2.
“My third example from Test & Trace is to understand why, for all Amber and Red international arrivals, the number of Day 8 PCR tests processed and registered is about one-seventh of the number of Day 2 PCR tests processed and registered: 53,000 versus 384 thousand in the last week of September 2021; 55,000 versus 473 thousand in the last week of August 2021. The same table does not provide PCR results but positive-rate on Day 2 cannot possibly be the explanation for the Day 8 shortfall.”
On booster vaccine stats:
“By 3 May 2021, 15.6 million citizens in UK had received their second COVID-vaccine; a tremendous achievement. Other things being equal, around 15 million should have received their booster by 3 November 2021 but, seemingly, only 9 million have done so, see https://coronavirus.data.gov.uk/details/vaccinations.
“Having been unable to book one’s booster until one-week after its due-date was an unnecessary design-fault which created a 2-week lag in practice.
“By 20 April 2021, 10.8 million citizens had received their second COVID vaccination, against which 2-week-lagged target the 9 million boosted by 3 November 2021 is a pretty decent performance. Especially when flu jabs are also being delivered and – judging by my own croaky voice – other respiratory viruses are already menacing!”
https://coronavirus.data.gov.uk/details/vaccinations
All our previous output on this subject can be seen at this weblink:
www.sciencemediacentre.org/tag/covid-19
Declared interests
None received.