Pneumococcal Antibody Concentrations and Carriage of Pneumococci more than 3 Years after Infant Immunization with a Pneumococcal Conjugate Vaccine

BACKGROUND: A 9-valent pneumococcal conjugate vaccine (PCV-9), given in a 3-dose schedule, protected Gambian children against pneumococcal disease and reduced nasopharyngeal carriage of pneumococci of vaccine serotypes. We have studied the effect of a booster or delayed primary dose of 7-valent conjugate vaccine (PCV-7) on antibody and nasopharyngeal carriage of pneumococci 3-4 years after primary vaccination. METHODOLOGY/PRINCIPAL FINDINGS: We recruited a subsample of children who had received 3 doses of either PCV-9 or placebo (controls) into this follow-up study. Pre- and post- PCV-7 pneumococcal antibody concentrations to the 9 serotypes in PCV-9 and nasopharyngeal carriage of pneumococci were determined before and at intervals up to 18 months post-PCV-7. We enrolled 282 children at a median age of 45 months (range, 38-52 months); 138 had received 3 doses of PCV-9 in infancy and 144 were controls. Before receiving PCV-7, a high proportion of children had antibody concentrations >0.35 µg/mL to most of the serotypes in PCV-9 (average of 75% in the PCV-9 and 66% in the control group respectively). The geometric mean antibody concentrations in the vaccinated group were significantly higher compared to controls for serotypes 6B, 14, and 23F. Antibody concentrations were significantly increased to serotypes in the PCV-7 vaccine both 6-8 weeks and 16-18 months after PCV-7. Antibodies to serotypes 6B, 9V and 23F were higher in the PCV-9 group than in the control group 6-8 weeks after PCV-7, but only the 6B difference was sustained at 16-18 months. There was no significant difference in nasopharyngeal carriage between the two groups. CONCLUSIONS/SIGNIFICANCE: Pneumococcal antibody concentrations in Gambian children were high 34-48 months after a 3-dose primary infant vaccination series of PCV-9 for serotypes other than serotypes 1 and 18C, and were significantly higher than in control children for 3 of the 9 serotypes. Antibody concentrations increased after PCV-7 and remained raised for at least 18 months

Medical students’ achievement on the Bachelor of Medicine, Bachelor of Surgery/Chirurgery Final Part I and II licensing examination: a comparison of students in problem-based learning, community-based education and service, and conventional curricula in Ghana

Purpose: Problem-based learning is an established method of teaching and learning in medical education. However, its impact on students’ achievement on examinations is varied and inconsistent. We compared the levels of achievement on the Bachelor of Medicine, Bachelor of Surgery/Chirurgery (MB ChB) Part I and II licensing examination of students in problem-based learning, community-based education and service (PBL/COBES), and conventional curricula. Methods: In 2014, we analyzed the MB ChB Final Part I and II licensing examination results of students in three classes (2004, 2005, and 2006) of the School of Medicine and Health Sciences, University for Development Studies, Tamale, Ghana. Ninety-three students in the 2004 and 2005 cohorts followed a conventional curriculum, and 82 students in the 2006 cohort followed a PBL/COBES curriculum. Using appropriate statistical tools, the analysis compared individual discipline scores and the proportions of students who received distinction/credit/pass grades among the classes. Results: The PBL students had significantly higher mean and median scores than the conventional students in Obstetrics and Gynecology, Internal Medicine, Community Health and Family Medicine, Surgery, and Psychiatry, but not in Child Health and Pediatrics. Also, a significantly (P=0.0010) higher percentage, 95.1% (n=78), of the PBL students passed all the disciplines, compared to 79.6% (n=74) of the conventional students. Conclusion: The PBL students significantly performed better in all the disciplines except child health and pediatrics, where the conventional students scored higher. These findings demonstrate that the benefits of the PBL/COBES curriculum are tangible and should be fostered

Linking agricultural adaptation strategies, food security and vulnerability:evidence from West Africa

Adaptation strategies to reduce smallholder farmers' vulnerability to climate variability and seasonality are needed given the frequency of extreme weather events predicted to increase during the next decades in sub-Saharan Africa, particularly in West Africa. We explored the linkages between selected agricultural adaptation strategies (crop diversity, soil and water conservation, trees on farm, small ruminants, improved crop varieties, fertilizers), food security, farm household characteristics and farm productivity in three contrasting agro-ecological sites in West Africa (Burkina Faso, Ghana and Senegal). Differences in land area per capita and land productivity largely explained the variation in food security across sites. Based on land size and market orientation, four household types were distinguished (subsistence, diversified, extensive, intensified), with contrasting levels of food security and agricultural adaptation strategies. Income increased steadily with land size, and both income and land productivity increased with degree of market orientation. The adoption of agricultural adaptation strategies was widespread, although the intensity of practice varied across household types. Adaptation strategies improve the food security status of some households, but not all. Some strategies had a significant positive impact on land productivity, while others reduced vulnerability resulting in a more stable cash flow throughout the year. Our results show that for different household types, different adaptation strategies may be 'climate-smart'. The typology developed in this study gives a good entry point to analyse which practices should be targeted to which type of smallholder farmers, and quantifies the effect of adaptation options on household food security. Subsequently, it will be crucial to empower farmers to access, test and modify these adaptation options, if they were to achieve higher levels of food security

A consort diagram indicating number of study participants per study group and visit.

<p>A consort diagram indicating number of study participants per study group and visit.</p

Nasopharyngeal carriage of <i>Streptococcus pneumoniae</i> before and after vaccination with a single dose of PCV-7.

<p>NA = Not applicable.</p><p>*Number of children.</p><p>**Number of serotypes (some children had multiple serotypes on a single visit: they have been included in all those serotype groups).</p>†<p>P value = 0.057 before Holm's correction for multiple significance tests.</p>‡<p>P value = 0.037 before Holm's correction for multiple significance tests.</p