Histo-Blood Group Antigen Null Phenotypes Associated With a Decreased Risk of Clinical Rotavirus Vaccine Failure Among Children <2 Years of Age Participating in the Vaccine Impact on Diarrhea in Africa (VIDA) Study in Kenya, Mali, and the Gambia

Background: Previously studied risk factors for rotavirus vaccine failure have not fully explained reduced rotavirus vaccine effectiveness in low-income settings. We assessed the relationship between histo-blood group antigen (HBGA) phenotypes and clinical rotavirus vaccine failure among children 4. Conclusions: Our study demonstrated a significant relationship between null HBGA phenotypes and decreased rotavirus vaccine failure in a population with P[8] as the most common infecting genotype. Further studies are needed in populations with a large burden of P[6] rotavirus diarrhea to understand the role of host genetics in reduced rotavirus vaccine effectiveness

Age-dependent association among Helicobacter pylori infection, serum pepsinogen levels and immune response of children to live oral cholera vaccine CVD 103-HgR.

Through its effects on gastric secretion, we hypothesized that Helicobacter pylori infection may influence oral immunization. Accordingly, we examined the association between H. pylori infection, serum pepsinogen (PG) (measures for H. pylori gastritis) and vibriocidal antibody (a correlate of protection) seroconversion following oral immunization with CVD 103-HgR live cholera vaccine among children of different ages.Sera from 422 Chilean children who were vaccinated with a single dose of CVD 103-HgR were tested by ELISA for serum IgG antibodies to H. pylori, PG I and PG II levels and antibodies to Shigella flexneri 2a lipopolysaccharide and hepatitis A virus (as markers of low socioeconomic status and exposure to enteric pathogens).The likelihood of vibriocidal antibody seroconversion following vaccination with CVD 103-HgR was significantly decreased in H. pylori-seropositive children age 6 months to 4 years with PG II>8 µg/L (adjusted OR 0.14 (95% CI 0.03-0.61; P = 0.009), and also in H. pylori seropositives with lower PG II level (adjusted OR 0.34, 95% CI 0.14-0.83; P = 0.017), compared to H. pylori-seronegatives. H. pylori-seropositive children aged 5-9 years with serum PG I>30 µg/L (indicating more severe gastritis) had higher odds of vibriocidal seroconversion than those with lower PG I levels (adjusted OR 4.41, 95%CI 1.26-15.38; P = 0.02). There was no significant association between exposures to S. flexneri 2a or hepatitis A virus and vibriocidal seroconversion.As H. pylori gastritis progresses with increasing pediatric age in developing country venues, changes in gastric secretion ensue that we believe explain the observed differences in age-related immune responses to immunization with live oral cholera vaccine. The effect of H. pylori and changes of gastric acid secretion on the immunogenicity of various oral vaccines should be studied in different developing, transitional and industrialized country settings

Logistic regression models of the association between <i>H. pylori</i> infection, serum pepsinogen levels and vibriocidal seroconversion after immunization with a single oral dose of CVD 103-HgR.

<p>Partially adjusted analysis, in addition to <i>H. pylori</i> serostatus/PG levels, age and sex were added to the analysis.</p><p>The following variables were entered: <i>H. pylori</i> infection, age (in years as a continuous variable), sex, PG I, PG II, PG I∶PG II ratio, baseline vibriocidal antibody titers (transformed into natural logarithm) <i>S. flexneri</i> 2a IgG and hepatitis A antibodies (as markers for environmental fecal contamination and low socioeconomic status). The final model of children aged <5 years included PG II and PG I∶PG II ratio but they were not significant, and gender (OR 0.42 95% CI 0.19–0.92, for Males vs. females). The final model of children aged 5–9 years included <i>S. flexneri</i> antibodies but it was not significantly associated with vibriocidal seroconversion.</p><p>In addition to <i>H. pylori</i>/PG II status, the following variables were entered to the analysis: age (in years as a continuous variable), gender, <i>S. flexneri</i> 2a IgG, hepatitis A antibodies and baseline vibriocidal antibody titers. The final model included the variables gender and hepatitis A, but they were not significantly associated with vibriocidal antibody seroconversion,</p

The association between <i>H. pylori</i> seropositivity, pepsinogen levels and vibriocidal seroconversion following vaccination with CVD 103-HgR.

<p>P for the difference between <i>H. pylori</i>-seropositive versus seronegative children.</p><p>P for trend.</p><p>PG analysis is based on 145 and 204 that belonged to children aged <5 years and 5–9 years, respectively.</p><p>163 and 200 samples were available for hepatitis A testing, and.</p><p>167 and 209 samples were available for testing <i>S. flexneri</i> IgG antibody for children aged <5 years and 5–9 years, respectively.</p

Mean serum pepsinogens levels in relation to the presence of IgG <i>H. pylori</i> antibodies and by age group.

<p>Data presented are mean levels and 95% CI. By ANOVA there was a significant difference between the age groups and according to serostatus (P<0.001 for PG I and PG II, and P = 0.002 for PG I∶PG II ratio).</p><p>Using the Bonferroni test that corrects for multiple comparisons a significant difference (P = 0.001) was noted in the serum PG II levels of <i>H. pylori</i>-seropositive vs. seronegative children aged <5 years.</p><p>Using the Bonferroni test, a significant difference (P<0.001) was also found for serum PG I levels in <i>H. pylori</i>-seropositive vs. seronegative children aged 5–9 years. Also, the mean serum PG I level among <i>H. pylori</i>-seropositive children aged 5–9 years was significantly higher than among <i>H. pylori</i>-seropositive children aged <5 years (P = 0.011). Other differences between the groups were not statistically significant.</p

The Prevalence (%) of <i>Helicobacter pylori</i> infection by age.

<p>The Prevalence (%) of <i>Helicobacter pylori</i> infection by age.</p

Immunization Coverage Surveys and Linked Biomarker Serosurveys in Three Regions in Ethiopia.

OBJECTIVE:Demographic and health surveys, immunization coverage surveys and administrative data often divergently estimate vaccination coverage, which hinders pinpointing districts where immunization services require strengthening. We assayed vaccination coverage in three regions in Ethiopia by coverage surveys and linked serosurveys. METHODS:Households with children aged 12-23 (N = 300) or 6-8 months (N = 100) in each of three districts (woredas) were randomly selected for immunization coverage surveys (inspection of vaccination cards and immunization clinic records and maternal recall) and linked serosurveys. IgG-ELISA serologic biomarkers included tetanus antitoxin ≥ 0.15 IU/ml in toddlers (receipt of tetanus toxoid) and Haemophilus influenzae type b (Hib) anti-capsular titers ≥ 1.0 mcg/ml in infants (timely receipt of Hib vaccine). FINDINGS:Coverage surveys enrolled 1,181 children across three woredas; 1,023 (87%) also enrolled in linked serosurveys. Administrative data over-estimated coverage compared to surveys, while maternal recall was unreliable. Serologic biomarkers documented a hierarchy among the districts. Biomarker measurement in infants provided insight on timeliness of vaccination not deducible from toddler results. CONCLUSION:Neither administrative projections, vaccination card or EPI register inspections, nor parental recall, substitute for objective serological biomarker measurement. Including infants in serosurveys informs on vaccination timeliness

Pentavalent Vaccine-3 Coverage in Serosurvey Participants by Each Coverage Estimation Method and Age Group (Toddlers 12–23 Months Old and Infants 6–8 Months Old).

<p>Pentavalent Vaccine-3 Coverage in Serosurvey Participants by Each Coverage Estimation Method and Age Group (Toddlers 12–23 Months Old and Infants 6–8 Months Old).</p