Health authorities in Blackburn with Darwen said they are extending the shielding guidance in the area until September 7.
NHS chiefs in the town said all residents who are on the Shielded Patient List are being sent letters and texts to advise them that the guidance has been extended for another three weeks.
Councillor Mohammed Khan, leader of the Blackburn with Darwen Council, said the measures "are there to protect our most vulnerable and save lives".
‘How a car crash saved my life’: Royal Preston patient recalls chance cancer diagnosis as hospital’s major trauma centre marks tenth anniversary
Lancashire dental crisis: Fulwood dental surgery Dentistry by Cure Clinics is offering free checkups this month
Cost of living crisis: Preston community centre hires mental health expert to help locals struggling with soaring food and energy prices
Freckleton care home where grandma, 91, was beaten to death is placed in special measures again after 'inadequate' CQC report
Preston great-grandmother who arrived in UK a penniless refugee gives £5k gift to renal unit at Royal Preston Hospital
The local NHS Clinical Commissioning Group said coronavirus levels in the area continue to remain higher than in the rest of the country and this is why shielding guidance in Blackburn with Darwen will not be relaxed.
Those patients who have been assessed as being clinically extremely vulnerable are strongly advised to continue to shield by staying at home as much as possible and keeping visits outside to a minimum.
The health authority has provided the following shielding advice for those who are being asked to reduce social contact for the next three weeks.
• you can meet in a group of up to 6 people outdoors, including people from different households, while maintaining strict social distancing (this excludes gardens);
• you no longer need to observe social distancing with other members of your household;
• If you are a single adult household (either an adult living alone or with dependent children under 18), you may from this date, if you wish, also form a ‘support bubble’ with one other household. All those in a support bubble will be able to spend time together inside each other’s homes, including overnight, without needing to socially distance.
Councillor Mohammed Khan, leader of the Blackburn with Darwen Council, said: "I want to again thank all our communities who are supporting our efforts to control the virus.
"The rates are still too high so the Government has announced that further easing measures are being postponed including the advice for people who have been shielding.
"I know this news will not be welcome for people who have already been shielding for such a long time but these measures are there to protect our most vulnerable and save lives."
Dr Qashuf Hussain, deputy medical director for Blackburn with Darwen and East Lancashire Clinical Commissioning Groups, said: "Clinically extremely vulnerable people are at high risk of suffering severe illness if they contract Coronavirus.
"The guidance is therefore for them to shield. I would strongly recommend that anyone in this category, that receives a text or a letter, should follow the guidance."
If you are currently in receipt of medicine deliveries or care through the national shielding service, you will continue to receive this support until September 7.
Priority supermarket delivery slots provided by seven supermarkets will also continue up until this date for those already signed up for support.
If a patient who needs to shield hasn’t received a letter but needs evidence for their employer, they can email [email protected]