Chemotherapy is a cancer treatment that destroys cancer cells. It causes a decrease in the number of white blood cells, causing the immune system to weaken.
White blood cells form part of the immune system that fights foreign cells, such as bacteria and viruses.
The researchers behind a 2021 review note that a weakened immune system may make people more prone to getting infections, including the virus that causes COVID-19. These may cause serious symptoms, and treatment may take a longer time to work.
Sometimes, people may face a life threatening situation and need immediate medical treatment.