PUBLIC health director for Blackburn with Darwen Dominic Harrison writes each week for the Lancashire Telegraph on the coronavirus crisis and response locally...

As of August 11, Blackburn with Darwen has a confirmed Covid-19 case rate of 77.9 per 100,000 and a positivity rate of 4.2 per cent. The positivity rate is the percentage of all those getting tested who test positive.

We are testing at a rate of 267 per 100,000 – the national average is about 94 per 100,000.

The Blackburn with Darwen case rate is thankfully coming down slowly from a peak two weeks ago of 92 per 100,000. We now have the third highest rate of confirmed cases in the national league table and are behind Pendle and Oldham.

One of the reasons Pendle’s rate has risen is that they have got their testing rate up to over 300 per 100,000. They are to be congratulated for this. Testing and subsequent self-isolation when confirmed positive is the best way to control spread of the virus.

We can only do this effectively though if we manage to trace all the contacts of confirmed cases. On Tuesday August 10 the government announced a change to the design of the national test and trace system which will shift to a more locally focussed way of working. I really welcome this.

The evidence we have from the national test and trace systems operation so far has been that it has only been able to complete contact tracing for about 54 per cent of our local cases and that the number of contacts per case it has recorded is low (about three per case).

This low rate of contact tracing completion has been a challenge to our capacity to control the community spread of Covid-19 in Blackburn with Darwen.

In the seven days to the August 4, Blackburn with Darwen had 121 confirmed cases. With only 54 per cent of the contacts being traced – even at a rate of three per case - this suggests a large number of residents will have a higher and un-notified risk of being positive for Covid-19 in the Borough. They will not have been directly contacted, may not therefore have got tested and are subsequently not self-isolating if positive.

For this reason, if you suspect you or anyone in your family has been a close contact of a confirmed case but have not been contacted by the national test and trace system – please can I urge you to get a test immediately.

Blackburn with Darwen Council has been working with the national system and has already taken on ‘case tracing’- i.e. contacting the confirmed cases that the national system could not contact in 48 hours. We are now managing to make contact with nine out of 10 of these cases and pass on their contacts to the national system for tracing. We want to take on contact tracing locally too.

On the evidence we have, Blackburn with Darwen Council believes we can radically improve the numbers traced and so boost our capacity to close down community transmission. We will do this by working closely with the national team as they make the changes now proposed.

We all need to work closely together to beat the virus.