If a person washed his hands for Netilat Yadayim, in order to eat bread, and before he dried his hands he heard a Beracha, Kaddish or Kedusha, is he allowed to answer "Amen" or respond to the Kaddish or Kedusha? Does such a response constitute a "Hefsek" (interruption) in between the washing and drying of the hands, or does the importance of responding to the Beracha override this concern?
Hacham Ovadia Yosef addresses this question in his work Yabia Omer (vol. 8, Orah Haim 20) and writes that the Halacha in such a case depends on whether or not the individual had recited the Beracha over the hand-washing ("Al Netilat Yadayim"). Once a person recites this Beracha, he must immediately dry his hands, and he may not make any interruption – even to respond to a Beracha or Kaddish – before drying his hands. If, however, one washed his hands and heard the Beracha before he recited the Beracha, then he should answer "Amen" and then recite the Beracha over the hand-washing. Of course, this would also apply to Kaddish and Kedusha. One may answer with the appropriate response only if he has yet to recite the Beracha of "Al Netilat Yadayim"; once he recited this Beracha, he may not say anything until he dries his hands.
