The Irish Blood Transfusion Service has accepted the advice of an independent advisory group led by a Tralee professor.
The Social Behaviours Review Group, which is chaired by Professor Mary Horgan, recommended that the IBTS make changes to its eligibility criteria.
This project, which includes changes to criteria related to gay and bisexual men, will be divided into two phases.
Phase one, which begins today, involves shortening the current deferral of gay and bisexual men from 12 months to four months.
This means that a man whose last sexual contact with another man was more than 4 months ago will be eligible to donate if he meets the other donor selection criteria.
The deferral of anyone who takes pre or post-exposure prophylaxis (PrEP or PEP), which are taken to reduce the risk of contracting HIV, has also been reduced from 12 to four months.
This is an interim measure and will be followed later in the year in Phase 2 by an individualised risk assessment of donors.
A spokesperson for the IBTS said the organisation will closely monitor the effects of these changes to ensure blood safety is maintained.
