The three remaining matches in the Women's Six Nations have been called off after tournament organisers took "the difficult decision to cancel".
Scotland's games in Italy and Wales will not take place and France v Ireland is also off as European measures to tackle Covid-19 continue.
England had already been confirmed as Grand Slam winners.
Meanwhile, Ireland and Scotland's qualifiers for next year's World Cup have been postponed.
Ireland, Scotland, Italy and the winner of the postponed Rugby Europe Women's Championship are due to feature in the tournament, which was scheduled for three weekends in December.
New dates will be announced "in due course", said an RWC spokesperson.
Ireland finish the Women's Six Nations third with three wins from four matches, Italy fourth, Scotland fifth, and Wales bottom.
And Six Nations Rugby chief executive Ben Morel said: "This was an extremely tough decision that was only taken after we had explored every possible option to get these matches played.
"It is especially disappointing that these cancellations come at a time when there is such positive momentum around the women's game and for the Women's Six Nations in particular.
"We will now, with our unions, put our focus and energy toward the 2021 Championship."