Attacker Marco Reus (ankle) has been ruled out of Brazil 2014, while there have been worries over goalkeeper Manuel Neuer, captain Philipp Lahm and midfielders Bastian Schweinsteiger and Sami Khedira.
Speaking ahead of his team's opener against Portugal on Monday, Low said the injuries were behind them.
"I think we are well prepared for this tournament," Low said.
"During the World Cup preparation, we had some injured players but that is done now.
"Manuel Neuer, Philipp Lahm, Bastian Schweinsteiger and Sami Khedira have all been able to train, they did well.
"I can assure you that all players are 100 per cent fit for tomorrow."
Low said his squad were 'highly concentrated and focused' ahead of the key encounter at the Arena Fonte Nova in Salvador.
Neuer said Germany were treating every game as a final.
"Ahead of the first match you are always in the situation that you don't really know where you are. After the match you obviously know more," Neuer said.
"I think all teams playing at the World Cup are very well prepared. We gave our very best to be prepared and tomorrow there will be our first match. We are looking forward for it.
"We know we are playing against a tough opponent who have played really well in recent years. So we start with a final, and that will continue in our group. Tomorrow we will know how good we really are."
