Helicobacter pylori-associated diseases, such as peptic ulcer and gastric cancer, are common in Vietnam, but the prevalence of the infection is largely unknown. A validated enzyme-linked immunosorbent assay was used for seroepidemiology with 971 samples from the general population, ages 0 to 88 years, with 546 samples from an urban population (Hanoi), and with 425 samples from a poor, rural province (Hatay). The overall seroprevalence of the infection was 746 per 1,000, with a prevalence of 788 per 1,000 in Hanoi and 692 per 1,000 in Hatay (P ‫؍‬ 0.0007). The risk for infection in the rural area of Hatay was 40% lower than in the urban population of Hanoi, with the odds ratio being 0.59 (95% confidence interval, 0.43 to 0.81). The study shows that the prevalence of H. pylori infection is high in Vietnam and especially high in a large urban area, such as the city of Hanoi.Helicobacter pylori infection causes gastritis and peptic ulcer disease and is a cofactor in the development of gastric cancer (16). The prevalence of H. pylori infection is decreasing in developed countries but remains high in many developing countries (11). Data on the epidemiology of H. pylori infection in Vietnam are scarce, but peptic ulcer disease and gastric cancer represent major health problems. In a large survey, conducted at the Hanoi Military Hospital from 1963 to 1983, peptic ulcer was found by endoscopy in 7.8% of 300,000 volunteers, ages 18 to 60 years (19). Official statistics for the year 2001 indicate an age-standardized incidence of 77.26 per 100,000 person-years for gastric and duodenal ulcer disease (4). Gastric cancer is the second-most-common cancer form in men and the third most common in women, with an agestandardized incidence of 23.7 and 10.8 per 100,000 personyears in the year 2000, respectively (12) Seroepidemiological investigations represent the most rapid and convenient way of obtaining a picture of the prevalence of H. pylori infection in a population, but the assays used need to be validated in the population studied (6,10,14). Enzymelinked immunosorbent assay (ELISA) for immunoglobulin G (IgG) detection can be based either on whole-cell sonicate antigen or on one or several purified components of the bacterium as the antigen. A majority of serological studies are now conducted with commercial kits that have been evaluated in developed countries. These commercial kits are often too expensive for developing countries, and use of a validated inhouse ELISA assay based on sonicate antigens would seem preferable.We have previously evaluated with both Swedish and Vietnamese populations an in-house ELISA based on sonicated H. pylori antigen, supplemented with an absorption step with sonicated Campylobacter jejuni antigen to remove cross-reacting antibodies (2, 6, 15, 17). The studies showed that the local strains used for the H. pylori antigen give a better diagnostic performance and also that the cutoff level used for serodiagnosis in the general population needs to be adjusted (6, 17). The aim of the present study wa...

Helicobacter pylori infection and peptic ulcer disease are common in developing countries, e.g., Vietnam. An enzyme-linked immunosorbent assay (ELISA) for screening of patients and for seroepidemiology is a useful tool but needs to be validated in the population studied. We used in-house ELISA with sonicated Swedish and Vietnamese strains as antigens to measure immunoglobulin G antibodies after absorption with sonicated Campylobacter jejuni in sera from 270 H. pylori culture-confirmed peptic ulcer patients, 128 Swedish ureabreath test and immunoblot-positive healthy controls, and 432 Vietnamese immunoblot-positive population controls. Sonicated whole-cell antigen based on the local strains showed a significantly better performance. Immunoblot-positive peptic ulcer patients had significantly higher antibody concentrations than immunoblotpositive population controls, necessitating a lower cutoff level if serology is used for screening or epidemiological purposes. The study shows that the parameters of ELISA for H. pylori need to be adjusted for the population being investigated.

Background. Maternal vaccination with an acellular pertussis (aP)–containing vaccine is a recommended strategy in a growing number of industrialized countries, to protect young infants from disease. Little is known on the effect of this strategy in low- and middle-income countries. Following a previous report on the effect of adding a pertussis and diphtheria component to the tetanus vaccination program in pregnant women in Vietnam, we report on infant immune responses to a booster aP vaccine dose in this randomized controlled clinical trial.Methods. Thirty infants of Tdap (tetanus, diphtheria, and acellular pertussis)–vaccinated pregnant women and 37 infants of women vaccinated with a tetanus-only vaccine received a fourth aP-containing vaccine dose in the second year of life. Blood was taken 1 month after the fourth infant dose. Immunoglobulin G (IgG) antibodies against pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (Prn), tetanus toxoid (TT), and diphtheria toxoid (DT) were measured using commercially available enzyme-linked immunosorbent assays (ELISA).Results. One month after the booster dose, significantly lower antibody titers were measured in the Tdap group for anti-TT IgG (P < .001) only. Anti-DT IgG, anti-PT IgG, anti-Prn IgG, and anti-FHA IgG antibody titers were comparable for both groups. A rise in antibody concentrations was elicited for all (except DT) antigens after boosting.Conclusions. The present results indicate that the blunting of infant pertussis responses induced by maternal immunization, measured after a primary series of aP vaccines, was resolved with the booster aP vaccine dose. These results add to the evidence for national and international decision makers on maternal immunization as a vaccination strategy for protection of young infants against infectious diseases.

The two treatments gave similar eradication rates. Significant differences for both treatments were found by weight, which could be the result of the once-daily proton pump inhibitor and clarithromycin and/or more antibiotic resistant strains in younger children.