Are local lockdown measures in Wales working? We look at the data

The question as to whether local lockdowns are working is what many people across Wales are asking. Some areas, like Caerphilly, have been under local lockdown restrictions for more than a month - it was the first local authority to go into a second form of lockdown on September 8th.Tighter measures have meant people not being able to leave their local area without a reasonable excuse, restrictions on who you meet, and mask wearing is now mandatory in many places.

So is all this disruption to our lives sending the virus into retreat?

Let's start with what the Welsh Government has told us about the effectiveness of local lockdowns in places like Caerphilly.

On 9 October, the First Minister said in a briefing: "Where the restrictions have been in place for longest, and that's in parts of South East Wales, there is evidence that the rise in cases has slowed and that the virus is beginning to come under control."

He was referencing this slide:

Welsh Government slide showing covid case numbers Credit: Welsh Government

It is true to say that case numbers per 100,000 people have fallen, but this slide only tells part of the story.What is not included is the number of tests carried out in Caerphilly at the same time.

Below is what the Public Health Wales data shows us when you compare the number of cases per 100,000 (orange lines) with the number of tests carried out per 100,000 (grey line).

As the number of tests has dropped, so have the number of cases.

The number of tests carried out and the number of cases per 100,000 have fallen in tandem Credit: Public Health Wales data

What was also not detailed in the Welsh Government's briefing was the percentage of tests that were returning a positive result.The chart below shows that while cases fell soon after lockdown - as did tests carried out - in recent days the percentage of tests that are coming back positive is rising. As are case numbers.

The percentage of tests coming back positive in Caerphilly is rising Credit: Public Health Wales data

The rise in the percentage of positive tests is seen as an indicator of how much virus is in the community and that while test numbers have fallen since lockdown was imposed, the data suggests many cases might be going undetected.

The same sort of trends can also be seen in other areas, like Blaenau Gwent, where case numbers and tests per 100,000 people fell in tandem as lockdown measures were introduced.

Cases and tests per 100,000 people have also fallen in tandem in Blaenau Gwent Credit: Public Health Wales Data

Jamie Jenkins, a former head of health statistics at the Office for National Statistics agrees that the data pattern from Caerphilly is repeated across other parts of the country.

Mr Jenkins said, "the dramatic fall in cases came at the time of a dramatic fall in tests - if you test less people you get less cases.

"This issue is not unique to Caerphilly with other areas having fewer cases when tests falls. We have no information if fewer tests were because fewer people have symptoms so do not want a test, or fewer people want a test because of restrictions if they are found positive.

"What is clear from the data is across the whole of Wales, the percentage of tests coming back positive has increased from around 2% in the middle of September to around 8% now. But ultimately the best indicator of the impact of the virus is the number of admissions to hospital and we are seeing that rise in Wales, but thankfully not at the same rate we saw in the Spring."

Mr Jenkins added: "If the percentage of positive tests in an area is rising this suggests the virus is spreading."

A Welsh Government spokesperson has responded insisting “testing capacity in areas under local restrictions has not reduced."

The spokesperson continued: "There has been greater use of targeted testing and the deployment of rapid community testing."

Credit: PA

As it stands, Welsh Government is looking into whether a new national lockdown will be required. At the same time, in an interview with the Spectator, the World Health Organisation has said that lockdowns should not be used as a primary tool against Covid. The World Health Organisation's Special Envoy on Covid-19, Dr David Nabarro, said in the interview: "We in the World Health Organisation do not advocate lockdowns as the primary means of control of this virus.

"The only time we believe a lockdown is justified is to buy you time, to reorganise, regroup, rebalance your resources, protect your health workers who are exhausted, but by and large we'd rather not do it."

Wales may well have bought some time, but the virus has far from gone away.