A group of MPs say the Government's lack of planning created a postcode lottery – with different areas reporting unacceptable variations in the number of people protecting themselves from the virus.
The Government originally asked those most vulnerable to Covid-19 to isolate at home in March last year – and NHS Digital figures show 8,320 people in the area were on the shielding list by April 12.
But, after doctors were asked to review the data, the patient count climbed to 17,495 by May 15 – an increase of 110%.
The latest update shows the number on the shielding list in the area has risen to 22,100 as of April 14 this year – 13,780 more than a year previously.
Northumberland residents missing out on almost £32 million in unclaimed benefits
Drop in the number of Covid cases in Northumberland
GP patient survey 2022: The 36 best rated doctor’s surgeries in Northumberland
Northumbria Healthcare reflects on first year of key pledge
Warning issued after thousands of illegal vapes seized in Northumberland
Nationally, reviews led shielding numbers to increase by 73%, but this varied hugely regionally.
The Commons Public Accounts Committee said the "unacceptable" level of variation was evidence of a postcode lottery, as the list grew from 1.3 million to 2.2 million nationally.
MPs also found that a contact centre established to trace those who did not respond to an initial shielding letter was unable to reach 800,000 people – and it is still not known whether they had been contacted by local authorities.
British Medical Association chair Dr Chaand Nagpaul said: “The shielding lists could have been created more quickly and effectively rather than shifting criteria and suddenly increasing the number of people on the list.
"This led to a huge rise in workload having to contact large numbers of people within a short time frame without comprehensive guidance."
The Government said it delivered an urgent national scheme to contact people and provide them with vital food and medicine so they could shield – but many chose not to take up the offer.
A spokesperson added: “These report findings are disappointing and misjudged.
“We have learned more about the virus and adapted our approach, which has enabled us to protect those most vulnerable by providing them with shielding guidance and prioritising them for vaccination.”