Confusion Over Whether Cases Are Rising or Falling

According to MailOnline, daily Covid cases in the U.K. fell for the ninth consecutive day in a row today.

Britain’s daily covid cases fell again today for the ninth day in a row, amid mounting confusion over true state of the third wave.
Department of Health bosses posted 29,622 cases – down 18.6% on last week.
In another glimmer of hope, hospitalisations (927) and deaths (68) appear to be slowing down – with both measures up just 6% on last Friday.

However, it cannot be true that daily cases have fallen for the ninth day in a row since they stood at below 25,000 on July 26th and now stand at 29,622. It appears that MailOnline means that this is the ninth day in a row in which the daily toll is less than it was exactly one week before.

Meanwhile, yesterday’s Guardian reported that daily cases had gone up for the second day in a row:

The daily number of Covid cases reported in the U.K. has risen for the second day in a row, although experts have cautioned against drawing premature conclusions from the fluctuations.
On Thursday, 31,117 cases were reported in the UK, up from 27,734 the day before, which marked the first rise in cases since July 20th.

To further complicate matters, the ONS published its weekly infection survey today and reported that the percentage of the population testing positive has increased slightly in England, Wales and Northern Ireland compared to the previous week, although it’s fallen in Scotland:

In England, the percentage of people testing positive for coronavirus (COVID-19) continued to increase in the week ending 24 July 2021, though there are possible signs that the rate of increase may have slowed; we estimate that 856,200 people within the community population in England had COVID-19 (95% credible interval: 798,600 to 915,000), equating to around 1 in 65 people.
In Wales, the percentage of people testing positive continued to increase in the week ending 24 July 2021; we estimate that 18,800 people in Wales had COVID-19 (95% credible interval: 12,700 to 26,000), equating to around 1 in 160 people.
In Northern Ireland, the percentage of people testing positive continued to increase in the week ending 24 July 2021; we estimate that 27,200 people in Northern Ireland had COVID-19 (95% credible interval: 18,200 to 38,200), equating to around 1 in 65 people.
In Scotland, the percentage of people testing positive has decreased in the most recent week ending 24 July 2021; we estimate that 49,500 people in Scotland had COVID-19 (95% credible interval: 38,300 to 62,300) equating to around 1 in 110 people.

The ONS’s results are less likely to be confounded by a decline in the number of people taking tests since it tests random samples of the population in the U.K.’s four nations. However, it’s worth bearing in mind that this survey is for the week ending July 24th, which is six days ago. It also suffers from bias towards people willing to take part in these kinds of surveys. Furthermore, the age breakdown suggests that there was a decline in prevalence among the population above the age of 16 (and under 70), in line with the PHE daily reports – it was only in children under 16 that prevalence continued to increase significantly. Perhaps the end of term meant that PHE testing is no longer picking up these children, who are no longer being tested by parents, especially with summer holidays approaching.

If you look at the daily toll as measured by date reported – which is the figure the MailOnline and the Guardian is referring to – it looks as if it peaked at 54,674 on July 17th, declined on the 18th and continued to decline on the 19th, then went back up again on the 20th, then declined for seven days consecutively, reaching a low of 23,511 on the 27th, then began to creep up again on the next two days consecutively, reaching a high of 31,117 yesterday and then declining to 29,622 today.

Let’s see what the weekend and next week’s ONS infection survey bring, but the falling daily case figures do offer a reason to be cautiously optimistic. So far, we haven’t seen the spike in daily cases caused by ‘Freedom Day’ that most public health experts predicted and we’re still a long way from Neil Ferguson’s estimate of 100,000 a day, which he said was “almost inevitable” after the easing of restrictions on July 19th.