England's Six Nations games against Italy on 14 and 15 March have been postponed because of the coronavirus outbreak.
The men's, women's and under-20s contests will be played at "a later date" say organisers.
"Six Nations fully intends to complete all 15 games in all three championships when time allows," they added.
Ireland's Six Nations games at home to Italy on 7 and 8 March were postponed last week.
Italy is the worst-hit European country with more than 3,000 cases.
Six Nations officials made the decision to reschedule the fixture on Thursday after the Italian government ordered all sporting fixtures in the country to be held behind closed doors until 3 April as part of measures to contain the outbreak.
The decree, announced by Italian Prime Minister Giuseppe Conte, affects all areas of the country, including those places were the virus has not been found.
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Playing the men's match behind closed doors would have meant the Italian Rugby Federation missing out on the ticket revenues from the 73,000-capacity Stadio Olimpico. The women's match was due to be played at the Stadio Plebiscito, a venue in Padua which holds about 10,000.
"We will refrain from making any rescheduling announcements while we keep assessing the situation," added organisers.
"Based on the information that is currently available, all other Six Nations matches are set to go ahead as scheduled."
|Remaining Six Nations fixtures|
|7-8 March||England v Wales|
|Scotland v France|
|Ireland v Italy||Postponed|
|14 -15 March||Wales v Scotland|
|Italy v England||Postponed|
|France v Ireland|
With their away match against Ireland this weekend already postponed, Italy's Six Nations campaign is now effectively over until their final two fixtures can be rearranged.
If France, who have three victories from three games so far in the championship, beat Scotland and Ireland in their final two games, they will clinch the men's title before Italy play their postponed games.
However any slip-up from the French could open the door for England and Ireland and mean the champions cannot be determined until Italy's rescheduled matches have been played.
Sergio Parisse, Italy's talismanic captain and winner of 142 caps, had planned to mark his international retirement with a farewell appearance against England.
The 36-year-old's previous plans to bow out of Test rugby in his country's final Rugby World Cup match against the All Blacks in October were wrecked by Typhoon Hagibis, which caused that pool game to be cancelled.
When could the match be replayed?
Space is scarce in the rugby calendar.
The first Saturday free of domestic and European action is 27 June, but playing Tests then would affect planned departures for summer tours with England heading to Japan and Italy due to play in the United States, Canada and Argentina.
When an outbreak of foot-and-mouth disease caused three of Ireland's games to be postponed during the 2001 Championship, the remaining fixtures were played in September and October, almost six months after the rest of the matches were completed.
Spectators who had been planning to head to Italy for this month's fixtures have three options if they booked through England's official travel company.
Fans are being offered the choice of rescheduling their booking for the revised date, an alternative fixture in the autumn or next year's Six Nations or a full refund.