Mourning is a coping-with-loss stage that prevents grief from becoming pathologic, i.e., complicated grief (CG) syndrome and persistent complex bereavement disorder (PCBD), recently included in international classification systems. During the COVID-19 pandemic, to contain virus spread, several countries adopted/adopt the prohibition of mourning rituals (funeral ceremonies/visiting to cemeteries), so that people were/are unable to give their hospitalized relatives the latest goodbye. Such measures can lead vulnerable individuals to develop CG and PCBD. We critically discuss literature-based risk factors for and protective resources against the onset of these conditions since the start of the pandemic and analyze prevention strategies to inform public health programs.