Is Cancer Contagious? What the Science Says

This page is for anyone who worries about catching cancer, including people living with or caring for someone who has it. It explains which infections are linked to cancer and why cancer itself does not spread between people.

Cancer itself is not contagious. You cannot catch cancer from another person, the way you catch a cold or the flu. Hugging, kissing, sharing food, or caring for someone with cancer will not give you cancer. But a few infections that spread between people are linked to a higher risk of certain cancers later on. That distinction matters. It is worth understanding clearly.

Some viruses, bacteria, and parasites raise the risk of specific cancers. These infections can spread from person to person. The cancer that sometimes follows, years later, does not spread that way at all. It is the infection that is transmissible. The cancer itself is not.

HPV (human papillomavirus) spreads through sexual contact. High-risk types of HPV cause nearly all cervical cancers. NCI says they also cause most anal cancers and many cancers of the throat and genital area. HPV vaccination and screening tests can prevent many of these cancers.

Hepatitis B and hepatitis C spread through blood and certain body fluids. Long-term infection with either virus can lead to liver cancer over time. Hepatitis B vaccination has been routine for U.S. infants since the 1980s. No hepatitis C vaccine exists, but newer treatments can cure hepatitis C.

Epstein-Barr virus (EBV) spreads mainly through saliva. It is linked to some lymphomas, and to nose and throat cancers.

H. pylori is a bacterium. It can spread through contaminated food or water and through mouth-to-mouth contact. Over many years, it can cause stomach cancer and a type of stomach lymphoma.

HIV weakens the immune system. NCI lists higher risks of Kaposi sarcoma, lymphomas, and cervical, anal, lung, liver, and throat cancers.

Vaccines exist for HPV and hepatitis B. Ask your care team about vaccination against these viruses. Ask too about testing for hepatitis B and C, and about routine cervical screening.

It is an understandable fear. Cancer is common and frightening. It sometimes clusters within families or communities, which can make it feel contagious even when it is not. Family clustering usually comes from shared genes, shared environment, or shared habits like smoking. It does not come from person-to-person spread of the cancer itself. If cancer runs in your family, that is worth discussing with your doctor. It is a genetic and environmental question, not a contagious one.

There is one rare, specific exception worth knowing about. In a small number of organ transplants, cancer cells from a donor's organ have been passed to the recipient, because the recipient's immune system is deliberately suppressed to prevent organ rejection. NCI puts that risk at about two cases of cancer per 10,000 organ transplants. This is not the same as catching cancer through ordinary contact. NCI notes that doctors avoid using organs from donors with a cancer history. This does not apply to everyday life.

If someone in your home has cancer, you do not need to change how you interact with them out of fear of catching it. NCI says cancer does not spread easily from person to person. Hugging, sharing meals, and helping with daily care do not pass on someone's cancer. If they are in treatment, ask their care team whether they need extra protection from germs.

• Have I ever been tested for hepatitis B or C? This matters most if you have never been vaccinated for hepatitis B.
• Does HPV vaccination make sense for me or my children, and up to what age is it recommended?
• What are my own risk factors if a cancer-linked infection runs in my family or community?

• National Cancer Institute — Infectious Agents and Cancer Risk
• National Cancer Institute — Common Cancer Myths and Misconceptions