Thousands fewer people in MK have taken a Covid test since the easing of restrictions, a Citizen study has revealed.
Government figures for the seven days leading up to July 16 show 13,007 PCR tests were taken in the borough and there were 1,244 positive cases that week.
But in the following seven days, leading up July 23, only 10,263 people took PCR tests, a reduction of 21.1%.
Analysis of both PCR and lateral flow test results show there were 806 positives - a drop of 2,744 (28%) compared to the previous week.
The World Health Organisation (WHO) has previously set 5% as a threshold after which point a pandemic can't be considered to be under control. At the peak of the second wave in January, Milton Keynes recorded a positivity rate of 23.5%.
The figures come as a drop in cases across England in recent days prompted hope that the current wave of infection has peaked – a trend that ended on yesterday and today.
Of those tested in Milton Keynes in the most recent week, 8.9% had at least one positive result, with duplicate positives for the same people removed.
That is down from 9.4% the week before, and currently places MK with the 198th highest positivity rate out of 315 councils in England.
When there are fluctuations in the number of cases it is always useful to look at the positivity rate. A decrease or increase in testing could heavily impact the number of overall cases - but it should not affect the positivity rate as more tests would also return more negatives unless the infection is genuinely spreading.
However, if the number of tests has fallen we can't definitively say that's what has caused a drop in cases. It could be the other way round and fewer people have symptoms, therefore fewer people are taking tests.
England’s positivity rate has climbed rapidly throughout June and July. In the seven days to 25 June it stood at 4%, rising to 6.1% in the week to July 2 and 7.8% in the week to 9 July. By July 23 it stood at 10.2%.
Figures released yesterday (Wednesday) show the number of UK cases reported in the last 24 hours – regardless of when the test was taken – rose to 27,734, up from 23,511 on Tuesday, and the first daily increase for seven days.
Today the figures rose further - to 31,117 new cases. In Mk, there have been 130 positives over the past 24 hours.
WHO set out its 5% positivity rate threshold in May last year, long before effective vaccines had been developed and rolled out. The threshold should be used to supplement estimates of the R-number – the rate of the virus’s transmission in communities – to assess whether the epidemic is under control, it said.
In England, 88.2% of adults had received at least one vaccine dose as of 27 July.
WHO has been asked if successful vaccination programmes would affect its guidance on test positivity. It has not yet responded.
Last year WHO recommended that governments should ensure the proportion of coronavirus tests coming back positive remains below 5% for at least two weeks before regions reopen.
The threshold is the maximum limit at which point a pandemic would be considered out of control, although positivity rates would ideally be far lower.