Research has shown that humans do develop an antibody response to infection with H. pylori, however, this natural
immune response is insufficient to either clear an infection or to prevent re-infection.1, 2
Rates of re-infection with H. pylori vary widely throughout the world. In people who have had eradication treatment,
re-infection rates range from 1% or less in developed countries to 11.5% or more in developing countries, reflecting
the underlying prevalence rate within those countries and therefore a varying risk of re-exposure.3, 4 Factors
associated with a higher risk of re-infection are similar to those that are reported to increase the initial prevalence
of H. pylori and include lower socioeconomic status, overcrowding and poor sanitation, ethnicity, age and gender. Re-infection
rates, for example, appear to be higher in children aged < 10 years and in adult males.5, 6 Presumably
the risk factors that increase re-infection within a high prevalence country will be similar to those that are at work
within a high prevalence community.
There is limited data on re-infection rates in New Zealand, however, a small Auckland based study from 1998 reported
a rate of 4% per year of follow up in patients treated for H. pylori.7 The rate referred to in the study
is the recrudescence rate (see below) because follow up of patients began at six months after eradication treatment.
The authors acknowledge that in other studies if patients who are followed up less than one year since treatment are
excluded, the rate decreases significantly and is likely to be due to re-infection rather than recrudescence.
Many studies looking at recurrence rates of H. pylori make a distinction, largely based on the time since initial
eradication, between two distinct mechanisms – recrudescence and re-infection. Recrudescence refers to a reappearance
of the original strain of H. pylori, usually within one year of initial eradication treatment.3, 4 This
generally reflects a failure of the eradication treatment* (estimated to be successful in approximately 80% of patients),2 due
to factors such as antibiotic resistance and poor patient compliance with the initial treatment regimen.3, 4 Re-infection
with H. pylori, at least one year after successful eradication, is regarded as the presence of a new infection usually
with a new strain of H. pylori or with a true re-infection with the original strain (as determined by DNA analysis).3,
If a patient has a recurrence of symptoms within one year of eradication treatment, it is likely that this will reflect
a relapse with the original strain of H. pylori and therefore an alternative treatment regimen should be considered,
e.g. bismuth-based quadruple treatment. Ensure that the patient understands the importance of completing the course
of treatment and that they are able to adhere to the dosing regimen. A further option is to refer the patient for endoscopy.
There is limited advice on what treatment should be offered to patients who present again after more than one year since
eradication and, depending on the individual circumstances, discussion with a Gastroenterologist is recommended.
For more information on H. pylori testing, see: “The
changing face of Helicobacter pylori testing” Best Tests, May, 2014.
* New Zealand guidelines do not recommend routine confirmation of eradication after triple treatment,
however, if patients have a recurrence of symptoms, important co-morbidities or complications such as peptic ulceration,
confirmation of cure with faecal antigen testing can be requested.
Thank you to Dr John Wyeth, Gastroenterologist, Clinical Leader, Capital & Coast DHB, Medical Director
PHARMAC and Dr Rosemary Ikram, Clinical Microbiologist, Christchurch, for expert review of this answer.
- Gorrell R, Wijburg O, Pedersen J, et al. Contribution of secretory antibodies to intestinal mucosal immunity against
Helicobacter pylori. Infect Immun 2013;81:3880–93.
- Moyat M, Velin D. Immune responses to Helicobacter pylori infection. World J Gastroenterol 2014;20:5583–93.
- Ryu K, Yi S, Na Y, et al. Rinfection rate and endoscopic changes after successful eradication of Helicobacter
pylori. World J Gastroenterol 2010;16:251–5.
- Calvet X, Lazaro M, Lehours P, et al. Diagnosis and epidemiology of Helicobacter pylori infection. Helicobacter
- Sivapalasingam S, Rajasingham A, Macy J. Recurrence of Helicobacter pylori infection in Bolivian children and
adults after a population-based ‘screen and treat’ strategy. Helicobacter 2014;[ePub ahead of print].
- Kim M, Kim N, Kim S, et al. Long-term follow-up Helicobacter pylori reinfection rate and its associated factors
in Korea. Helicobacter 2013;18:135–42.
- Fraser A, Schreuder V, Chua L, et al. Follow up afer successful eradication of Helicobacter pylori: symptoms and
reinfection. J Gastroenterol Hepatol 1998;13:555–9.