Helicobacter pylori (H. pylori) is a bacterium that can live in the lining of the human stomach.
According to research, H. pylori is one of the most common chronic bacterial infections worldwide. In many countries, a significant proportion of the adult population is infected, yet most people are completely unaware of it.
Thanks to its unique survival mechanisms, the bacterium can persist in the stomach for decades if left untreated.
Once it colonizes the stomach, H. pylori causes inflammation of the stomach lining. Virtually everyone who is infected develops chronic gastritis, although the severity of inflammation varies considerably. In some people, the inflammation remains mild and causes no symptoms, while in others it may eventually lead to complications such as peptic ulcer disease or precancerous and cancerous changes in the stomach lining.
The prevalence of H. pylori depends on geographic region, age, and socioeconomic conditions. Infection most commonly occurs during childhood. Countries with lower sanitation standards tend to have higher infection rates, whereas prevalence has gradually declined in developed countries due to improved living conditions and better access to diagnostic testing.
It is important to understand that detecting H. pylori does not automatically mean that a person has a disease or will develop symptoms.
Most infected individuals:
- do not experience abdominal pain or heartburn;
- never develop stomach ulcers;
- never develop stomach cancer.
This is why two people with the same infection may have completely different outcomes: one may never experience any symptoms, while the other may eventually develop peptic ulcer disease.
Why Do Doctors Pay So Much Attention to H. pylori?
The International Agency for Research on Cancer (IARC) classifies Helicobacter pylori as a Group I carcinogen, meaning there is sufficient scientific evidence that it increases the risk of gastric cancer.
However, it is important to understand that having the infection does not mean cancer is inevitable.
The vast majority of infected individuals will never develop stomach cancer.
For this reason, modern medicine considers H. pylori not simply a feature of the stomach microbiome but an infection that, in certain situations, should be identified and treated to help prevent serious diseases in the future.
How Is Helicobacter pylori Transmitted?
The exact mechanism of transmission has not been fully understood.
However, current scientific evidence has identified several likely routes of transmission.
Humans are considered the only significant reservoir of the infection. This means that H. pylori is transmitted from one infected person to another.
Unlike many gastrointestinal infections, H. pylori is not easily spread through casual contact. In most cases, transmission requires prolonged close household contact, particularly among family members.
Main Routes of Transmission
Oral-to-Oral Transmission
The bacterium may spread through saliva and oral secretions, for example by:
- sharing dishes;
- sharing eating utensils;
- tasting food with the same spoon.
However, finding H. pylori in saliva does not mean that every such contact results in infection.
Fecal-to-Oral Transmission
This is considered the most likely route of transmission in regions with poor sanitation.
The bacterium may be shed in the stool of an infected person and subsequently spread through:
- contaminated drinking water;
- unwashed hands;
- contaminated food.
This explains why infection rates are closely associated with sanitation, access to clean water, and hygiene standards.
Gastric-to-Oral Transmission
This route may occur through exposure to the vomit of an infected individual.
During vomiting, the bacterium may enter the environment and potentially infect others. Although this route is considered less common, it has been supported by several scientific studies.
Can You Catch H. pylori Through Kissing?
This is one of the questions patients ask most frequently.
Theoretically, transmission through kissing is possible because H. pylori has been detected in saliva and dental plaque.
In practice, however, adults rarely become infected through kissing alone. Most research suggests that transmission primarily occurs during childhood, rather than between adult partners.
Therefore, if one spouse has H. pylori, it does not necessarily mean that the other partner is infected or will become infected.
Can You Catch H. pylori from Sharing Dishes?
This route cannot be completely ruled out.
However, the risk of becoming infected simply from occasionally sharing a cup or plate is considered low.
More important risk factors include:
- living in the same household;
- prolonged close contact among family members;
- close contact between parents and young children.
Should Family Members Be Tested?
According to current international guidelines, testing first-degree relatives may be considered only in selected situations.
These include:
- gastric cancer diagnosed in the patient;
- atrophic gastritis;
- multiple cases of gastric cancer within the family;
- residence in regions with a high incidence of gastric cancer.
If H. pylori is diagnosed in one spouse, routine testing of the other spouse is generally not required.
However, testing may be discussed with a physician if:
- the partner has upper gastrointestinal symptoms;
- there is a family history of gastric cancer;
- one partner is undergoing eradication therapy and infection in the other partner needs to be excluded.
Should Children Be Tested?
If parents are infected with H. pylori, routine testing of all children is not recommended.
Testing is considered only when there are clear medical indications, such as:
- chronic abdominal pain with suspected organic disease;
- peptic ulcer disease;
- unexplained iron deficiency anemia.
Current pediatric guidelines do not support a "test-and-treat" strategy for all children.
Can You Become Infected Again After Treatment?
Yes. Reinfection is possible.
However, after successful eradication therapy, reinfection in adults is uncommon—occurring in less than 1–3% of patients per year. More often, a positive follow-up test reflects failed initial eradication rather than true reinfection, meaning that some bacteria survived the original course of treatment.
For this reason, confirming successful eradication is essential.
Follow-up testing should be performed:
- at least four weeks after completing antibiotic therapy;
- at least two weeks after stopping proton pump inhibitors (PPIs).
Current international guidelines recommend using non-invasive tests to confirm successful eradication.
Key Takeaways
Helicobacter pylori is an extremely common infection that causes no symptoms in most people.
However, in appropriate clinical situations, identifying and treating the infection can:
- help prevent peptic ulcer disease;
- eliminate one potential cause of iron deficiency anemia;
- reduce the risk of developing gastric cancer.
If you experience upper abdominal pain or discomfort, unexplained iron deficiency, have a history of peptic ulcer disease or atrophic gastritis, or have close relatives with gastric cancer, it is worth discussing H. pylori testing with your physician.
The choice of diagnostic test and the need for treatment always depend on the individual clinical situation.
If you would like to determine whether testing is appropriate in your case, choose the most informative diagnostic method, or interpret your existing test results, schedule a consultation.
During your appointment, we will carefully review your medical history, assess your individual risks, and develop a personalized diagnostic and treatment plan if necessary.