Refugee status is designed to protect people who are personally at a high risk to their life or safety if they were returned. For example if you were a prominent political, labour or women’s rights activist and the state actively wishes to kill or imprison you. Refugee status is a permanent offer; you will be allowed to remain in Ireland permanently and become an Irish citizen.
Subsidiary protection is for people who are not personally at a high risk to their life, freedom or safety. For example, you are not personally sought by the police but the general conditions in your country, such as war or widespread civil unrest, make it unsafe to return anyone there. Subsidiary protection is granted for a specific period of time, usually three years. If the situation in your home country improves in this period then it may be revised.
Subsidiary protection does not allow for family reunification while refugee status does. Carefully consider whether this is an important issue to you.