The strain, officially named AY.4.2, spreads more easily than other variants and now accounts for more than half of analysed cases in one part of the country: the Torridge area of Devon.
Officials designated the strain a ‘variant under investigation’ on October 20.
Scientists are still working out whether it is more transmissible or whether there are other factors helping it to spread.
Vaccines are proving as effective against Delta Plus as they are against other Delta variants, two separate studies have found.
And there is “no evidence of increased severity based on risk of hospitalisation or death”, the UK Health Security Agency (UKHSA) has said.
Here is the situation in every area of Derbyshire:
1. Amber Valley
In Amber Valley, of 116 samples analysed in the week up to November 13, 14.7 per cent were found to be of the Delta Plus strain. Image for illustration only. Photo: Brian Eyre
2. Bolsover
In Bolsover, of 30 samples analysed in the week up to November 13, 16.7 per cent were found to be of the Delta Plus strain. Image for illustration only. Photo: Marisa Cashill
3. Chesterfield
In Chesterfield, of 106 samples analysed in the week up to November 13, 14.2 per cent were found to be of the Delta Plus strain. Image for illustration only. Photo: Brian Eyre
4. Derbyshire Dales
In Derbyshire Dales, of 32 samples analysed in the week up to November 13, 6.2 per cent were found to be of the Delta Plus strain. Image for illustration only. Photo: Paul Robinson