select search filters
roundups & rapid reactions
before the headlines
Fiona fox's blog

expert reaction to latest data from the ONS Infection Survey

The Office for National Statistics (ONS) have released the latest data from their COVID-19 Infection Survey.


Prof James Naismith, Director of the Rosalind Franklin Institute, and University of Oxford, said:

“Today’s ONS data show that in Scotland and England more than 1 person in every 100 has covid19.  Wales and Northern Ireland have less, around 4 in 1000.

“These data show that up to last Saturday, the delta wave has continued to grow, as expected.  This is the last ONS update we will get before the quasi end of restrictions on Monday.  It is a reasonable assumption that the wave has continued to grow this week and will accelerate after Monday.  We are doubling cases every 12 to 18 days.  Vaccination will act as a drag on the rate of spread thankfully.

“The vaccine roll out across US, EU, UK, China and other developed countries is encouraging.  Tragically, delta will cause a catastrophe in less developed countries where vaccination coverage is low.

“New cases of Delta will lead to long covid, hospital admissions and deaths.  The ratios between these have been massively changed by the safe and effective vaccines we are administering but the link is not eliminated.

“As a rough guide, on the 21st June 15, 955 positive cases were recorded, 8 days later, 29th June 366 people admitted to hospital with covid19, 9 days later, (8th July) 33 people died with covid19.  These ratios vary by day chosen, need more in depth counting and of course Delta may behave differently than previous waves (time to hospital and time to death).  Nonetheless they should help shape expectations of the range of outcomes from our experiment in the UK.

“The ONS data are generally regarded as the gold standard, this is because it’s method of sampling consistently tests a cross section of the population.  The ONS data show a steady increase in cases.  This is contrast to the daily totals of positive cases reported by the testing system, these appeared to show a plateau last week; this was not the case.  The Zoe app showed the same thing and claimed cases peaked at 33000.  With 48000 cases yesterday, this claim has been proven wrong.  Similarly the statement that new cases in Scotland halved is not borne out by ONS data which indicate prevalence increasing, with perhaps some evidence of slow down in the rate increase.

“Both Zoe and daily test data are valuable.  However, my concern based on the data, is that they are not accurately capturing the evolution of this wave of Delta at this point in time.  As we anticipate an acceleration in viral spread, policy prescriptions based on these data run the risk of starting from the wrong point.  It will be two to three weeks until we see in ONS data the outcome of the experiment.  Other consequences may manifest prior to that.”



All our previous output on this subject can be seen at this weblink:



Declared interests

None received.

in this section

filter RoundUps by year

search by tag