England prop Mako Vunipola is in self-isolation as a precaution due to coronavirus fears after flying back from Tonga via Hong Kong.
He was set to link up with Eddie Jones' squad on Monday for a training camp, with a view to featuring in Saturday's Six Nations match against Wales.
But the 29-year-old did not join the rest of the group and will miss the fixture after being advised to self-isolate under current NHS guidelines, according to the PA news agency .
"Mako is not in camp on medical grounds. He is not sick, but it is a precaution," a Rugby Football Union spokesperson said.
Vunipola is not expected to play again in the tournament and had originally been expected to miss the clash with the Grand Slam champions after travelling to Tonga recently for unspecified personal reasons.
There have been 51 coronavirus cases in the UK, while the first confirmed case of the virus in Hong Kong occurred on January 23.
It has since risen to 100 cases in the Chinese city, and Vunipola is now expected to spend the next 14 days in self-isolation despite showing no symptoms.
Ireland's game against Italy has been postponed because of coronavirus, but Six Nations organisers said on Monday that the rest of the weekend's fixtures were set to go ahead.
There had been fears that the games on March 14 between Italy and England in Rome and France and Ireland in Paris would be called off.
But representatives of the Six Unions and championship officials met in Paris on Monday and agreed that the two matches and the other games in England, Scotland and Wales over the final two rounds of the competition would take place.
"As it stands today, based on the latest information, all Six Nations matches currently scheduled are set to go ahead," organisers said.
"Six Nations is in contact with FIR [Italy's Rugby Federation] and RFU [England's Rugby Football Union] regarding the possibility of relocating the Women's and U20 Italy vs England matches to another Italian location and we will make a further announcement on this in due course.
"However, the Italy vs England senior men's match in Rome is planned to go ahead as scheduled."
The organisers said they intended to complete all 15 games across the three championships but would not commit to rescheduling fixtures while the situation was being assessed.