Abstract
Coronavirus disease 2019 (COVID-19), is a pandemic that resulted in extreme human and economic losses. A higher incidence of morbidity and mortality to COVID-19 was demonstrated in a special population. Factors that impact the disease severity include old age, obesity, pregnancy, diabetes mellitus, cancer, and immunosuppressive drugs. Fortunately, several COVID-19 vaccines were developed such as Pfizer-BioNTech, Moderna, Oxford-AstraZeneca, and Johnson & Johnson among others. These vaccines have shown good efficacy and safety profiles in the general population, but serious rare adverse effects were reported related to specific vaccines. Several studies are undergoing to test the efficacy in special populations. Reduced efficacy or delayed immunological response to COVID-19 vaccines were suggested for patients with autoimmune disorders or organ transplant patients, especially those receiving certain medications such as rituximab. There is a concern about organ rejection in organ transplant patients. Despite these facts, there is an agreement among health care providers to consider prioritization of the above-mentioned groups for receiving vaccinations with the same precautions followed for the general population. It is recommended to ongoing studies determine the efficacy and safety of COVID-19 vaccines in patients with comorbidities based on clinical data.