The second largest Catholic diocese in Ireland has suspended the sign of peace at Mass until the end of the flu season.
Down and Connor, which covers Belfast and takes in three counties, said its recommendations were based on medical advice.
Parishioners celebrating Mass at the weekend were informed that handshakes between worshippers had been halted.
It is the second time in a year that restrictions have been put in place.
In January, the 'sign of peace' was suspended in Down and Connor amid fears over the potential spread of the Australian flu virus.
In 2009, during the swine flu epidemic, Catholic churches across much of the UK also took similar steps.
A spokesperson for the diocese told BBC News NI that the suspension was expected to last into next year and it would be "reviewed upon further medical advice at the end of the flu season".
The Irish News reported the diocese has called on anyone suffering from flu to stay at home and parishioners attending to wash their hands before and after Mass.
It is also encouraging parishes to install hand sanitisers at the entrance to churches.