Vunipola was named in a 34-man squad on Monday but the Rugby Football Union (RFU) said he did not come into camp after travelling through Hong Kong on his return from Tonga over the weekend.

"Mako is not in camp on medical grounds," said an RFU spokesperson.

"He is not sick but it is a precaution."

Vunipola missed England's victory over Ireland on 23 February after flying to Tonga for family reasons.

But his return flight took him through virus-hit Hong Kong, and he has now gone into an isolation period.

It is believed Vunipola has shown no symptoms of the illness, with his absence from the England set-up a precaution.

Travellers returning from areas where the virus is prevalent are being asked to self-isolate if they have symptoms. Those in self-isolation should stay at home for 14 days.

He is therefore unlikely to be available for England's Six Nations finale against Italy in Rome, which is due to go ahead as planned on Saturday, 14 March.

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 currently set to go ahead.