He called on the government to correct the mistake, which left many people confused and fearful.
Greater Manchester, parts of Lancashire and West Yorkshire have been subject to targeted lockdowns, following a spike in Covid-19 cases.
The infection rate has increased in nine of the ten boroughs – some dramatically – over the past week.
Despite this, the guidelines have been relaxed so that clinically extremely vulnerable people are no longer asked to protect themselves.
From August 1, the government suspended armor plating unless transmission of Covid-19 in the community begins to increase significantly.
Shielding will continue in areas like Blackburn and Leicestershire due to local lockdown measures, but not in Greater Manchester.
A woman, whose sister-in-law has provided protection throughout the pandemic, wondered if it is safe to return to work.
In a message on Twitter, the woman said: “Can someone please explain to me how safe it is for my sister-in-law, who is now protecting, to go back to work at a hospital in Salford?
“AKA Greater Manchester where was there another local lockdown?” “
Andy Burnham replied, “I can’t. The protection policy should have been extended to areas subject to the new restrictions.
” It’s as simple as that. Ending it the day after the changes left a lot of people confused and fearful.
“The government was completely wrong and should correct it today. ”
Many people living in Greater Manchester said they were shocked to receive a message from the government on Friday evening telling them to stop protecting themselves.
Clinically vulnerable people include transplant recipients, people with specific cancers, conditions such as severe asthma, cystic fibrosis and chronic obstructive pulmonary disease, and heart disease.
Deputy Chief Medical Officer Dr Jenny Harries said last month: “The shield was introduced to protect those who, at the start of the UK epidemic, were considered clinically most vulnerable in our communities.
“We know how difficult this time has been and the impact of protecting the mental health of many people.
“The prevalence of the virus in the community is now lower and the chances of getting infected are reduced, so we think it’s a good time to relax some of the advice so people can start to return to some level of normalcy. in their daily life. . ”
The government has written to everyone on the protected patient list with up-to-date information on protective advice and the ongoing support that will be available to them.