• In 2018, there were estimated 2.2 million cancer cases worldwide due to infections, representing 13% of all cancer cases. (Lancet Glob Health 2020;8:e180)
• Helicobacter pylori (HP) and human papillomavirus (HPV) are the top two carcinogenic infectious pathogens, each accounting for 35% and 32%, respectively.
• Hepatitis B virus (HBV), Epstein-Barr virus (EBV) and hepatitis C virus (HCV) together, contribute to approximately 30% of cancer cases caused by infectious pathogens.
• Other pathogens, including human herpesvirus type 8 (HHV8), Schistosoma haematobium, human T cell lymphotropic virus and liver flukes (namely Opisthorchis viverrine and Clonorchis sinensis), are responsible for approximately 2% of all infection attributable cancer.
• HIV is not a direct pathogen that causes cancer, but it contributes to the development of cancer via immunosuppression. When there is coinfection of HIV with EBV, or HHV8, or HPV, some cancers, such as lymphoma, Kaposi sarcoma or cervical and anal cancer, can arise in the infected patients. For this reason and to avoid miscounting, HIV was not included in the calculation.

Adapted from de Martel et al., Lancet Global Heath, 2020


Table 1. Estimation of infection population attributable fractions from cancer cases in 2018

Infectious agent	Cancer site	Global population attributable fraction* (%)
H. pylori	Noncardia gastric cancer	89
	Cardia gastric cancer	20
	Non Hodgkin lymphoma of gastric location	74
Human papillomavirus	Cervix uteri carcinoma	100
	Anus squamous cell carcinoma	100
	Vagina carcinoma	78
	Vulva carcinoma	27
	Penis carcinoma	51
	Oropharyngeal carcinoma	23
	Oral cavity cancer	1
	Larynx cancer	1
Hepatitis B virus	Hepatocellular carcinoma	76
Hepatitis C virus	Hepatocellular carcinoma	5
	Other non Hodgkin lymphoma	2
Epstein-Barr virus	Nasopharynx carcinoma	85
	Burkitt lymphoma	59
	Hodgkin lymphoma	51
Human herpesvirus type 8	Kaposi sarcoma	100
Human T cell lymphotropic virus	Adult T cell leukemia and lymphoma	100
Opisthorchis viverrini and Clonorchis sinensis	Cholangiocarcinoma	4
Schistosoma haematobium	Bladder squamous cell carcinoma	1

Adapted from de Martel et al., Lancet Global Heath, 2020

*Population attributable fraction (PAF) is calculated by dividing the number of new cases attributable to infectious pathogens by total number of new cases in 2018.

Helicobacter pylori (HP)

• 760,000 new cases
• Male:female = 1.81:1
• Causes gastric cancer mainly at noncardia subsites
• Highest incidence of HP related gastric cancer in Eastern Asia
• Eradication of HP with antibiotics is the most effective strategy to prevent gastric cancer.

Human papillomavirus (HPV)

• 694,500 new cases
• Male:female = 1.7:1 (incidence for nongenital cancer, including oropharyngeal, oral cavity, larynx and anal cancer)
• In female, cervix uteri has the highest number of carcinoma cases (80%) caused by HPV.
• In male, oropharyngeal carcinoma is the top cancer caused by this virus and is four times higher than that in female.
• Highest incidence of HPV related cancer in Sub-Saharan Africa and in low middle and upper middle income countries
• Attributable fractions: 100% for cervix uteri carcinoma and anus squamous cell carcinoma

Hepatitis B virus (HBV)

• 360,000 new cases
• Male:female = 3:1
• Causes hepatocellular carcinoma
• Highest incidence of HBV related cancer in Eastern Asia
• Attributable fraction: 76%

Hepatitis C virus (HCV)

• 148,070 new cases
• Male:female = 2.5:1 (hepatocellular carcinoma)
• Causes other non Hodgkin lymphoma equally in male and female
• Highest incidence of HCV related cancer in Western Asia and Northern Africa, followed by North America
• Attributable fractions: low (≤ 5%) for both hepatocellular carcinoma and non Hodgkin lymphoma

Epstein-Barr virus (EBV)

• 148,910 new cases
• Male:female = 2.6:2 (nasopharynx carcinoma) or 1.5:1 (Hodgkin lymphoma or Burkitt lymphoma)
• Highest incidence of EBV related cancer in Southeastern Asia
• Attributable fractions: 51 - 85% (varied by EBV related cancer types)
• EBV vaccines in development
  • National Institute of Heath (Immunity 2019;50:1305, Front Immunol 2021;12:734471)
  • mRNA vaccine developed by Moderna in Phase 1 trials (Eclipse Trial: An Epstein-Barr Virus (EBV) Vaccine Clinical Trial [Accessed 25 April 2022])

Human herpesvirus type 8 (HHV8)

• 42,000 new cases
• Male:female = 2:1
• Causes Kaposi sarcoma
• Highest incidence of HHV8 related cancer in Sub-Saharan Africa
• Attributable fraction: 100%

Schistosoma haematobium

• 5,900 new cases
• Male:female = 2:1
• Causes squamous cell carcinoma of the bladder
• Endemic areas in Africa and Middle East
• Attributable fraction: 1%

Human T cell lymphotropic virus

• 3,600 new cases
• Male:female = 1:1
• Causes adult T cell leukemia and lymphoma
• No endemic areas
• Attributable fraction: 100%

Opisthorchis viverrine and Clonorchis sinensis

• 3,400 new cases
• Male:female = 1.6:1
• Causes cholangiocarcinoma
• Attributable fraction: 4%

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