World Rugby insist the injury levels seen during England 2015 to date are not "extraordinary in any way" and are in line with previous World Cups.
The total number of withdrawals from the competition so far is 21, whereas in 2011 the figure for the entire event read 19. Both figures are considerably lower than eight years ago when 37 players were forced home early.
England's defeat to Wales and Ireland's victory over France were particularly attritional, but World Rugby chief executive Brett Gosper insists the attention on those games has led to the belief that the injury rate has increased.
"Our early indications are that England 2015 is not tracking any differently to any other tournament in the past," Gosper said.
"Visually it is looking more serious because of the size of two of the games where injuries have been happening, but our monitoring is not showing the number to be extraordinary in any particular way.
"Let's wait until the tournament is over before doing a full analysis. We want to make sure it's evidence based rather than emotionally based because player welfare is our number one priority."