Immunocompromised persons have significantly impaired immune system. This includes persons with the following conditions: a) Transplant patients on medications that suppress the immune system, including solid organ and allogenic stem cell transplants b) Cancer patients on active treatment with chemotherapy or on other therapies that suppress the immune system c) Haematological cancers d) Treatments for non-cancer conditions that suppress the immune system e) End-stage kidney disease f) Advanced or untreated HIV. Persons with the above conditions are recommended to receive the COVID-19 vaccine. For immunocompromised persons who are unvaccinated: They should receive three initial doses of an mRNA vaccine. This comprises a second dose eight weeks after the first dose and a third dose eight weeks after the second dose, as part of an enhanced three-dose primary series. For immunocompromised persons who are vaccinated: They should receive an additional dose of the updated vaccine at an interval of around one year (and at least five months) from their last dose. For better protection and in consultation with their treating physician, they can be considered to receive the additional dose from five months after their last dose.