NHS England data reveals that 5,445 people in the area were set to receive letters urging them to avoid leaving their home except for in certain circumstances, such as to exercise or attend health appointments, as of February 22.
It took the total number of people advised to shield in the area to 22,230 – a 32% increase.
The initial shielding list included people with single risk factors such as those with various cancers, people on drugs which suppress the immune system or those with severe respiratory conditions.
It has been expanded after scientists developed a new system to assess whether someone is at risk – taking in factors including age, ethnicity, body mass index, other health conditions and also postcode, which is indicative of levels of deprivation.
Those newly identified will get priority access for vaccines if they have not yet received a jab due to their age.
Nationally, an extra 1.7 million people have been identified as clinically extremely vulnerable – up from 2.2 million previously.
Dr Jenny Harries, deputy chief medical officer for England, said: “All of these people are those who have not had an individual clinical condition that we’ve previously been able to identify through the clinically extremely vulnerable group, but they are people who have multiple personal risk factors and underlying health conditions which move them into a higher risk group.”
Current advice states that shielding should continue until at least March 31.