Pope very popular in United States, but no 'Francis effect' - poll

Pope Francis blesses the altar during Ash Wednesday at Santa Sabina Basilica in Rome March 5, 2014. REUTERS/Max Rossi

(Reuters) - One year after his election, Pope Francis is "immensely popular among American Catholics," a survey said on Thursday, but there is no sign of a "Francis effect" inspiring more to attend Mass or do volunteer work.

The Washington-based Pew Research Center said 85 percent of Catholics in the United States viewed the Argentine-born pontiff favourably, with 51 percent reporting a "very favourable" view of him, while only 4 percent expressed a negative opinion.