Can H. pylori Be Transmitted?
Yes, H. pylori can be transmitted from person to person, making it a contagious infection that affects approximately 50% of the world's population. 1, 2
Primary Routes of Transmission
The most likely modes of transmission are person-to-person through:
- Oral-oral route (through vomitus or possibly saliva) 2, 3
- Fecal-oral route (through contaminated food, water, or poor hygiene) 2, 3
- Waterborne transmission via fecal contamination, particularly in areas with untreated water 2
The only definitively proven mode of transmission is iatrogenic spread through contaminated endoscopy equipment, though this represents a minor route compared to community transmission. 2, 3
Evidence Supporting Person-to-Person Transmission
Intrafamilial clustering is well-documented, with first-degree relatives of infected patients having a 2-3 times increased risk of infection. 1 If multiple first-degree relatives have gastric cancer (which is strongly associated with H. pylori), the risk increases 10-fold. 4
Additional evidence includes:
- Higher infection rates among institutionalized children and adults, supporting close-contact transmission 2
- Detection of H. pylori DNA in vomitus, saliva, dental plaque, gastric juice, and feces 2
- Childhood as the major period of acquisition, particularly in developing countries 2, 3
Risk Factors for Transmission
Poor sanitation and crowded living conditions facilitate transmission:
- Inadequate sanitation practices 2
- Low socioeconomic status 2
- Crowded or high-density living conditions 2
- Contaminated food prepared under suboptimal conditions 2
- Exposure to contaminated water or soil 2
Protective factors include:
- Improved sanitation and hygiene (recommended by the World Health Organization as primary preventive measures) 1
- Adequate nutritional status 2
- Frequent consumption of fruits, vegetables, and vitamin C 2
Clinical Implications for Healthcare Providers
The European Society of Gastrointestinal Endoscopy recommends testing and treating first-degree relatives of patients with gastric cancer if they test positive for H. pylori. 1 This reflects the recognized familial transmission pattern and the goal of preventing gastric cancer in high-risk individuals.
Given the contagious nature:
- Consider screening household contacts of infected patients, particularly in families with gastric cancer history 1
- Emphasize hygiene education as part of management 1, 2
- Recognize that most infections occur during childhood, making early intervention potentially important 2, 3
Future Prevention Strategies
Vaccination would be the ideal solution for eliminating H. pylori infection in populations, as recommended by the Centers for Disease Control and Prevention, though this remains under development. 1 The Maastricht IV/Florence Consensus Report emphasizes that "a major effort should be made to develop a vaccine against H. pylori in humans." 4
A recent large field trial in China showed >70% efficacy with an oral recombinant urease B vaccine in teenagers, providing optimism for future vaccine development. 4
Important Caveats
- Humans are the principal reservoir; while H. pylori has been found in some domestic cats and sheep, these are not considered major sources of human infection 2, 3
- The organism can exist in a coccoid form in the environment, though it remains unclear if this form can revert to cause infection 3
- Transmission via houseflies has been hypothesized but lacks definitive evidence 2