No; cancer is not a contagious disease and is not easily passed from one person to another; caring for, hugging or living with a patient carries no risk of getting cancer [1]. The only situation in which cancer passes from one person to another is an organ or tissue transplant from a donor with a history of cancer, and this risk is very low (about 2 cases in every 10,000 transplants) [1]. Some viruses and bacteria, such as HPV, hepatitis B and C and Helicobacter pylori, can be passed on and raise the risk of cancer, but the cancer they cause is not contagious [1, 2].
Why is cancer not contagious?
Cancer is caused by harmful changes (mutations) in the genes of a person's own cells; about 90 to 95 per cent of cancers result from mutations that happen during life with ageing and exposure to environmental factors such as tobacco smoke and radiation [1]. One person's cancer cells cannot grow in another person's body through contact, kissing, sharing food or using shared items; the only known exception is an organ or tissue transplant, which is very rare thanks to donor screening [1].
Being close to, caring for and living with someone with cancer does not expose you to cancer [1]; external radiotherapy does not make the patient radioactive either, and being near them is safe, even for children and pregnant women [5]. On the other hand, a patient having chemotherapy may have low white blood cells and be vulnerable to infection; if you have a cold or an infectious illness, keep your distance and wash your hands regularly and well [6].
Infections that raise the risk of cancer
| Infectious agent | How it spreads | Related cancers | Prevention or treatment |
|---|---|---|---|
| High-risk human papillomavirus (HPV) | Sexual contact | Almost all cervical cancers; most anal cancers; many cancers of the oropharynx, vagina, vulva and penis | HPV vaccine and cervical screening |
| Hepatitis B virus | Blood, from mother to baby at birth, sexual contact | Liver cancer | Hepatitis B vaccine |
| Hepatitis C virus | Blood, from mother to baby at birth | Liver cancer | New treatments can cure the infection |
| Helicobacter pylori | Probably contaminated food and water, and mouth-to-mouth contact | Stomach cancer (non-cardia) and gastric MALT lymphoma | Diagnosis and treatment with antibiotics |
| Epstein-Barr virus (EBV) | Saliva, sexual contact, blood transfusion and organ transplant | Some lymphomas and nasopharyngeal cancers | Almost everyone in the world becomes infected, and most have no symptoms |
| HIV | Blood and sexual contact | Not cancer-causing itself, but by weakening the immune system it raises the risk of Kaposi sarcoma, lymphoma and cancers of the cervix, anus, lung, liver and throat | Highly effective antiviral treatment |
According to an analysis of GLOBOCAN data, about 2.2 million cancer cases worldwide in 2018 were attributed to infection; Helicobacter pylori with 810,000, HPV with 690,000, hepatitis B with 360,000 and hepatitis C with 160,000 cases were the main causes [3]. Preventing these infections has a real effect: in a study of more than 1.6 million Swedish girls and women, the incidence rate ratio of invasive cervical cancer was 0.12 in those vaccinated before age 17 and 0.47 in those vaccinated at age 17 to 30, compared with the unvaccinated [4].
Related questions
Is cervical cancer passed on through sex?
Does surgery or a biopsy make cancer spread in the body?
The chance is very low; surgeons use standard methods, such as separate instruments for each area, to prevent cancer cells from spreading [1].
Does exposing a tumour to air during surgery make cancer worse?
No. Contact with air does not make a tumour grow faster or cause cancer to spread [1].
Related cancer types
Related questions
References
6 referencesShow all references, 2 with a study cardClose the reference list
Numbers in the text, such as [1], refer to these sources. Sources with a “Study card” button are summarised in the site’s evidence library.
- 1
- 2
- 3Global burden of cancer attributable to infections in 2018: a worldwide incidence analysis
- 4HPV Vaccination and the Risk of Invasive Cervical Cancer
- 5External Beam Radiation Therapy for Cancer
- 6Infection and Neutropenia during Cancer Treatment
This page is based on reputable scientific sources and was last updated on 28 October 2026. The content of this website is for educational and informational purposes only and does not replace consultation, diagnosis or treatment by a specialist physician. Consult your treating physician about any treatment decision.
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