Boris Johnson had to self-isolate after coming into contact with a MP who tested positive for Covid-19.
On Thursday, the prime minister held a 35-minute meeting with a group of MPs, including Lee Anderson, who later tested positive for the virus.
Mr Johnson has no symptoms of Covid-19 and will continue to work on Downing Street, his official spokesman said.
The prime minister nearly died earlier this year while battling the coronavirus.
Critical care medics at St. Thomas' Hospital in central London supplied "liters and liters" of oxygen to Mr Johnson as his chances of survival were up to date.
The news of Mr Johnson's second stay in isolation comes the day before the major government relaunch after the last few days brought political chaos to Downing Street.
Events culminated in Prime Minister Svengali Dominic Cummings dramatically storing his belongings in a box out the doorstep of No. 10 carried employees.
Boris Johnson (left) had to self-isolate after coming into contact with MP Lee Anderson (right) who tested positive for Covid-19
On Thursday, the prime minister held a 35-minute meeting with a group of MPs, including Lee Anderson, who later tested positive for the virus. Pictured: The Prime Minister and Mr Anderson meeting on Thursday
Ashfield MP, Mr Anderson (pictured with Mr Johnson in a file picture) – part of Mr Johnson's Red Wall that helped him win the 2019 general election – posted on Facebook that he was isolating
Ashfield MP, Mr Anderson, who was part of Mr Johnson's Red Wall and helped him win the 2019 general election, shared a picture of himself and Mr Johnson on Facebook after the meeting.
The couple stood at a safe distance from each other in the picture with the caption: “Breakfast with the Prime Minister. I met the Prime Minister at number 10 this morning.
I went there with my wish-list for Ashfield and Eastwood. The investment is coming, you have my word on it. & # 39;
wrote on Facebook tonight: & # 39; Isolate.
I lost my sense of taste on Friday when my wife had a severe headache. I had no cough, no fever and felt fine. We both had a test on Saturday and the result came on Sunday morning.
& # 39; My wife and I both tested positive. I'm absolutely fine and my biggest concern is my wife, who is in the screened group. But we both feel good. & # 39;
According to government guidelines, those who come in contact with people who test positive are required to isolate for 14 days.
Boris Johnson speaks of self-isolation on April 3rd, just days before he was rushed to the hospital
St. Thomas & # 39; s Hospital where Prime Minister Boris Johnson was held overnight
Boris Johnson looks at a get well soon card sent by children when he contracted coronavirus
The Prime Minister was informed that he had come into contact with an infected person through the NHS Test and Trace app.
A Prime Minister's spokesman said: "The Prime Minister was informed today by NHS Test and Trace that he must self-isolate as a contact from someone who has tested positive for Covid-19.
& # 39; The Prime Minister will obey the rules and is self-isolating.
He will continue to work on Downing Street leading the government's response to the coronavirus pandemic.
"The PM is good and has no symptoms of Covid-19."
During an interview in May, the Prime Minister revealed how serious his condition became after his positive diagnosis in April.
Doctors were ready to announce his death if he lost his coronavirus battle, the prime minister said, admitting he was "a lucky man".
Mr Johnson acknowledged that he was "not in great shape" fighting the disease at St. Thomas' Hospital in central London, and was given "liters and liters" of oxygen when medics fought to keep it up to keep the intensive care unit alive.
He recalled his frustration at not being able to shake off the virus and how the sobering experience enabled him to see the "fantastic" care the NHS provided.
"I realized that it was getting pretty serious," he told the sun on Sunday.
"And I remember saying to myself," How do I get out of there? "
He added, “To be honest, the doctors had all sorts of plans about what to do if something went wrong.
“I wasn't in great shape because the oxygen levels in my blood continued to drop.
“But it was thanks to wonderful, wonderful care that I made it. You really did it and made a huge difference. & # 39;
The Prime Minister said that nurse Luis Pitarma, 29, and sister Jenny McGee, 35) watched over him for 48 hours and gave him the necessary care.
In a video recorded shortly after he was released, Mr. Johnson thanked the "absolutely brilliant" doctors and praised the nurses for their "amazing" care.
Nurse Jenny McGee (left) and nurse Luis Pitarma (right) were recognized by Prime Minister Boris Johnson for their praise after treating him during his stay in intensive care
He said, “I want to thank the many nurses, men and women, whose care has been so amazing. I'm going to forget some names so forgive me, but I want to thank Po Ling and Shannon and Emily and Angel and Connie and Becky and Rachael and Nicky and Ann. & # 39;
Mr. Johnson reserved special recognition for two other people whom he referred to as "Jenny from New Zealand, Invercargill in the South Island and Luis from Portugal near Porto".
He continued, "The reason my body ended up getting enough oxygen was because for every second of the night they watched and thought and took care of the interventions I needed."
Ms. McGee has been in the UK for eight years after studying here and then moving to St. Thomas in central London.
Before that, she worked for six years at the Royal Melbourne Hospital, where she completed her intensive training.
29-year-old Pitarma was born in Aveiro, just 30 miles from Porto, and is believed to have moved to London in 2014 after completing his medical training in Lisbon.
The paramedic was thanked by Portuguese President Marcelo Rebelo de Sousa in a phone call on Sunday.
A statement from the Portuguese President's Office said: “Marcelo Rebelo de Sousa would like to highlight the special recognition that British Prime Minister Boris Johnson has given Portuguese nurse Luis Pitarma for his work and care during his time in intensive care.
& # 39; The President of the Republic has already personally thanked the nurse Luis Pitarma. On his behalf, he also thanks the commitment of all Portuguese health professionals who are providing crucial assistance in the fight against the pandemic in Portugal and around the world.
"A word of encouragement, also addressed to professionals of other nationalities who are doing an invaluable service to Portugal in strengthening the National Health Service."
(tagsToTranslate) Dailymail (t) Nachrichten (t) Boris Johnson (t) Coronavirus