Helicobacter pylori

June 15, 2023

NCCID Disease Debriefs provide Canadian public health practitioners and clinicians with up-to-date reviews of essential information on prominent infectious diseases for Canadian public health practice. While not a formal literature review, information is gathered from key sources including the Public Health Agency of Canada (PHAC), the USA Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO) and peer reviewed literature.

This disease debrief was prepared by Signy Baragar. Questions, comments, and suggestions regarding this disease brief are most welcome and can be sent to nccid@manitoba.ca.

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Questions Addressed in this debrief:

  1. What are important characteristics of H. pylori?
  2. What is the current risk for Canadians from H. pylori?
  3. What is the prevalence of H. pylori in Canada?
  4. What measures should be taken for a suspected H. pylori case or contact?

What are important characteristics of H. pylori?

Characteristics and Causes

Helicobacter pylori (H. pylori) is a gram-negative, microaerophilic curved or S-shaped bacterium that infects the inner lining of the stomach. H. pylori produces a urease enzyme which neutralizes stomach acids and produces chronic inflammation on the stomach lining.

H. pylori infection can last a lifetime in a host if not properly treated. Most people are unaware that they have H. pylori and show no signs of infection. Others can develop long-lasting inflammation in the stomach lining, called chronic gastritis.

H. pylori infection is one of the main causes of gastric (stomach) cancer and duodenal peptic ulcer disease (PUD). It can also lead to mucosa-associated lymphoid tissue (MALT) lymphoma.


Most people infected with H. pylori do not show any symptoms. However, some people will develop chronic gastritis because of an inflamed and damaged stomach lining. H. pylori can also lead to painful peptic ulcers in the stomach lining or duodenum.

The most common symptoms of H. pylori infection include an upset stomach, nausea, or vomiting. Other symptoms include:

  • loss of appetite
  • weight loss
  • burning sensation or a feeling of fullness in the stomach
  • belching or hiccups
  • blood in the vomit or melena (black or tarry stools) associated with PUD

The symptoms of H. pylori infection may be caused by other stomach problems, and provider confirmation is needed for diagnosis.

Severity and Complications

H. pylori is a major cause of gastric cancer and duodenal peptic ulcer disease. Nearly all gastric cancer cases and duodenal ulcers are related to H. pylori infection. However, the risk of developing severe complications from H. pylori is low. About 1 in 10 people infected with H. pylori will develop an ulcer, while less than 3% of people will develop stomach cancer.

H. pylori infection can also increase the risk of developing MALT lymphoma. MALT (mucosa associated lymphoid tissue) lymphoma is a cancer of the lymphatic system that starts in the inner lining (mucosa) of the organs and body cavities. Most people with MALT lymphoma have previously been infected with H. pylori. However, the risk of developing MALT lymphoma for people infected with H. pylori is very low (less than 1%).


The exact way H. pylori spreads is unknown. H. pylori is believed to be transmitted mainly through the fecal-oral route, but also possibly by direct contact with saliva, vomit, or through contaminated food or water. This usually happens during childhood.

Prevention and Control

Practicing good hand hygiene can reduce the risk of acquiring an H. pylori infection, especially when preparing food. Good hand hygiene involves washing hands with soap and water for at least 20 seconds or using a hand sanitizer. Other ways to reduce the risk of H. pylori infection include drinking clean water and ensuring that food is properly prepared.


There is currently no licensed vaccine to prevent infection with H. pylori. Several organizations and academic institutions have recently initiated developing an H. pylori vaccine. However, all vaccines remain in the early development stage.

A 2010 Government of Canada Safety Data Sheet for H. pylori states that a combination of recombinant urease (rUrease), a parenteral vaccine containing H. pylori antigens (CagA, VacA, NAP), and aluminum hydroxide as an adjuvant may be effective against infection.


Most people do not need to be tested for H. pylori if they do not show signs of infection. A healthcare provider can determine whether H. pylori testing is required.

There are invasive and non-invasive tests to diagnose an H. pylori infection. Invasive testing usually involves performing an endoscopy procedure to look inside the body.

Non-invasive testing can be done in 3 ways:

  1. Stool antigen test – checks for antigens to H. pylori
  2. Urea breath test – checks for H. pylori in the stomach
  3. Blood test – checks for antibodies to H. pylori

Stool antigen and urea breath tests are the preferred non-invasive tests for H. pylori infection due to having higher testing accuracies.


Treatment for H. pylori infection involves taking a combination of antibiotics and a proton pump inhibitor (PPI) to reduce the amount of acid in the stomach (acid suppression). This involves administering either a CLAMET-PPI (Clarithromycin, Amoxicillin, Metronidazole, PPI) or BMT-PPI treatment regime (Bismuth subsalicylate, Metronidazole, Tetracycline, PPI) for 14 days.

Other lines of treatment exist in case of initial treatment failure or in cases ofpenicillin/amoxicillin allergies. More information on H. pylori treatment regimens is available at the following links:

Treatment in Pregnancy

There is limited clinical data to guide H. pylori treatment in pregnant and breastfeeding individuals. Some studies suggest delaying H. pylori treatment in asymptomatic pregnant patients until after pregnancy and after cessation of breastfeeding. For symptomatic pregnant patients in the first trimester, a triple therapy regime involving a proton pump inhibitor, amoxicillin, and metronidazole may be used safely. Clarithromycin triple therapy with amoxicillin may be used safely in the second and third trimesters.

H. pylori is associated with an increased risk of severe nausea and vomiting during pregnancy (hyperemesis gravidarum). For pregnant patients with hyperemesis gravidarum, treatment decisions should be balanced with careful consideration regarding fetal risks alongside symptom relief from select drug therapies.



H. pylori infection is one of the most common chronic bacterial infections – just over half of the world’s population (4.4 billion people) is infected. In Canada, the overall prevalence of H. pylori is between 20-30%. However, certain groups in Canada have higher rates of infection. This includes Indigenous communities as well as individuals that have immigrated from high prevalence areas in South America, Africa, and Asia.

            Incubation Period

The incubation period for H. pylori infection is unknown. This is because symptoms may not be present or may not develop until adulthood.

What is the current risk for Canadians from H. pylori?

Certain factors can increase the risk of acquiring H. pylori. The most-cited risk factors in the literature include:

  • lower socioeconomic status
  • crowded living conditions
  • lack of adequate sanitation

Other risk factors include smoking, a lower consumption of fruits, consumption of uncooked or under cooked contaminated food or water, and a family history of gastric cancer or peptic ulcer disease.

What is the prevalence of H. pylori in Canada?

Surveillance data for H. pylori outbreaks are not publicly available across the regions of Canada. In general, the prevalence of H. pylori in Canada is considered to be 20-30%. However, a 2019 study estimated the prevalence in Indigenous communities across the circumpolar north to be over 60%. This contrast reflects substantial inequity in the disease burden of H. pylori for Indigenous communities in Canada.

What measures should be taken for a suspected H. pylori case or contact?

Case Definition

There is no standard case definition for Helicobacter pylori in Canada.

Identifying and Reporting

No information is available for national, provincial, and territorial surveillance as H. pylori is not a reportable disease in Canada.