The official website of the Vatican seems to be silent on this issue. Nevertheless it may be up to the local ordinary to make special norms for the diocese in question!
The following is taken from Redemptionis Sacramentum of the Vatican:
[160.] Let the diocesan Bishop give renewed consideration to the practice in recent years regarding this matter, and if circumstances call for it, let him correct it or define it more precisely. Where such extraordinary ministers are appointed in a widespread manner out of true necessity, the diocesan Bishop should issue special norms by which he determines the manner in which this function is to be carried out in accordance with the law, bearing in mind the tradition of the Church.