There is no evidence from COVID-19 vaccine clinical trials or controlled follow-up data that links WHO-approved COVID-19 vaccines with increased risks of cancer or HIV/AIDS.

Most scientists have seen a decrease in cancer incidences. Estimates suggest that at least 20% of people have had to delay medical care and treatment during the pandemic, including testing for and diagnosis of cancer.

Several studies show that COVID-19 vaccines generate key immune-boosting white blood cells, called helper and killer T cells, specific to COVID-19. These help organize immune system responses and then kill cells that are infected with the COVID-19 virus. T cells play a large role in defending the body against viruses and bacteria, as well as diseases like cancer. COVID-19 vaccines have not been shown to suppress T cells and there is no evidence that shows coronavirus vaccines weaken the immune system, or make people more susceptible to cancer or other illnesses like autoimmune diseases.

There is also no possibility of HIV/AIDS transmission from the COVID-19 needle. A new needle is used every time, and there are  no data that show an increase in HIV cases among vaccinated individuals. In addition, among individuals living with HIV, clinical trials of WHO-approved COVID-19 vaccines have not shown any increase in the development of AIDS among individuals with HIV.

The United States Centers for Disease Control and Prevention recommend that people who are moderately to severely immunocompromised receive COVID-19 vaccines and, in some people with cancer, a booster shot as well. Many expert medical groups recommend that most people with cancer or a history of cancer get the COVID-19 vaccine once it’s available to them. Cancer patients tend to be more susceptible to severe disease due to the diseases' impact on the immune system and cancer treatments, in some cases, impacting the ability of the immune system to fight off additional infections.