1 June 2020

Facts about Covid19 data for the city – setting the record straight

We have very serious concerns about a recent local news article about the R number for Brighton & Hove.

Calculating the R rate is very complex. It involves data from lots of different sources.

The calculations include information relating to such things as confirmed cases, hospital admissions, deaths, patient surveys and testing.

When these are all put together and interpreted by experts they give regional and national R numbers.

Robust calculations of the R number come from a joint study from Public Health England and the University of Cambridge and also from the London School of Hygiene and Tropical Medicine.

It is not possible to calculate meaningful R values at a very local level, such as one specific for Brighton & Hove. 

This is because some of the data involves such low figures that even a small change in them can, in statistical terms, make a disproportionately big relative difference.

For example, the increase from 1,000 and 1,009 is less than 1%. But the difference between 10 and 19 is still only 9 cases, but is a 90% increase.

Locally we are reviewing early warning indicators on a daily basis. They include:  

To date, the rate of diagnosed cases has been relatively low compared to the national picture. The number of 111 and 999 calls and hospital admissions for Covid all currently remain low.

However, there has been a small increase recently in the number of cases. We and our NHS colleagues are monitoring this situation very closely.

We also know that data on tests at commercial laboratories, so for example those being tested at the Amex site, are not within the data made available and once this is included we will see an increase in cases due to more people being tested.

In addition, in the coming weeks data from the national Test and Trace system will start to feed into these calculations. This system will start to pick up cases that aren’t currently being tested for.

It is very likely that because of this there will be a rise in both local and national figures when these data start coming through.

I’d also like to reassure you that we're doing everything we can as a council to support residents and continue to deliver excellent services through the pandemic.

We would urge all our residents to continue to take responsibility and respect the restrictions around social distancing. This is the best way for everyone to protect themselves and their loved ones.

Alistair Hill, Director of Public Health for Brighton & Hove City Council