Faculty of Applied and Computer Science

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Browsing Faculty of Applied and Computer Science by Author "Adrian, P. V., Dr."

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    Correlation of saliva and serum antibody titre response to pneumococcal capsular polysaccharides
    (Vaal University of Technology, 2017-10) Madimabe, Metsekae Richard; Adrian, P. V., Dr.; Grobler, C. J., Dr.
    Background: Infants and young children under the age of 2 years are vulnerable to Streptococcus pneumoniae infections, especially those who are born in developing countries. Antibiotic therapy was an effective treatment until resistance to antibiotics emerged, and then vaccines were developed to assistant with the treatment. The first successful conjugate vaccine was the 7-valent pneumococcal conjugate which resulted in a decrease in vaccine serotype IPD in infants and children below the age of two years. Objectives: The main aim of this study was to assess the saliva and serum antibody concentration response to pneumococcal capsular polysaccharides in children vaccinated and unvaccinated. Design: This is a sub-study within a retrospective analysis of a prospective cohort study on the safety and immunogenicity of 7-valent pneumococcal polysaccharide-protein conjugate vaccine (PncCV) and the immunogenicity of a H. influenzae type b conjugate vaccine (HibCV). Setting and participation: Infants aged between ≥ 4 and ≤ 10 weeks were enrolled, who only received BCG and Polio vaccine following birth. Infants were enrolled according to HIV status during routine antenatal screening in the obstetrics wards of the two hospitals, in Johannesburg and Cape Town. Measurements: Saliva IgG and IgA concentrations against pneumococcal capsular polysaccharides serotype 4, 6B, 7F, 9V, 14, 18C, 19F and 23F were quantified a by multiplex bead-based assay using the Luminex technology. Serum IgG against polysaccharides serotype 4, 6B, 7F, 9V, 14, 18C, 19F and 23F were measured by a competitive Enzyme Linked Immuno-Sorbent Assay (ELISA). Results: Post three primary vaccine doses, both serum IgG and saliva IgG and IgA antibody concentrations to vaccine serotypes were protective in children who received the vaccine. The antibody concentration in children whom did not receive the vaccine was much lower in comparison to the vaccine group in both serum and saliva to vaccine serotypes (P = 0.0001). And also high positive correlation (>0.6) was observed of IgG in serum and in saliva following vaccination. Conclusion: Pneumococcal conjugate vaccines induce pneumococcal capsular polysaccharide specific antibodies in both serum and saliva. However, there are differences between the vaccines’ ability to induce mucosal immune response and there are also serotype specific differences in the antibody concentrations and in the proportion of positive samples after a series of vaccinations. The pneumococcal conjugate vaccine in this study was able to induce mucosal immune memory: the anti-pneumococcal IgA concentrations also increased with age in the saliva of unvaccinated children.
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    The evaluation of whole blood cytokine assay for diagnosis of M.tuberculosis infection in South African children with household tuberculosis contact
    (Vaal University of Technology, 2019-04) Masilo, J. M.; Adrian, P. V., Dr.; Grobler, C. J., Dr.
    Background: There are critical unmet needs for improved strategies in the detection and diagnosis of M.tuberculosis infection in children, and for prevention of tuberculosis disease in children. Bacillus Calmette-Guérin (BCG) vaccination has limited the utility of tuberculin skin testing (TST) in areas with high vaccine coverage. Objectives: The aim of this study was to estimate the prevalence of M.tuberculosis infection in children with household tuberculosis contacts, using QFT-GIT testing in comparison with TST. Methods: This study was a cross-sectional design to assess the performance of a new T-cell based blood test, namely QuantiFERON-TB Gold In Tube (QFT-GIT), for diagnosis of tuberculosis infection in the children (n=182) of adults (n=124) with pulmonary tuberculosis, additionally to determine the prevalence of M.tuberculosis infection in children with household tuberculosis contacts, using QFT-GIT testing in comparison with TST. The study was carried out at Chris Hani Hospital. For children involved in the study, tuberculosis exposure information was obtained, together with TST, QFT-GIT, and HIV testing. Data obtained from both experiments was statistically analysed using SPSS version 24 to determine whether there was a significant agreement between QFT-GIT and TST on the detection of M.tuberculosis prevalence in children with house hold contacts with confirmed M.tuberculosis infection. Results: This study examined the sensitivity and specificity of the QFT-GIT tests compared with the standard TST for diagnosing latent tuberculosis disease in paediatric contacts. Because of the lack of a latent tuberculosis "gold standard”, the specificity and sensitivity of QFT-GIT was calculated with a two-by-two table method. The specificity of the QFT-GIT was 84% and the sensitivity was 85%. There was a good correlation between QFT-GIT and TST (Cohen’s kappa of 0.705). Seventeen percent (17%) of the 182 children tested by QFT-GIT yielded indeterminate results. Age was associated with indeterminate QFT-GIT results in paediatric tuberculosis contacts. Point prevalence for QFT-GIT was recorded as 31% at baseline and 39.5% after six months indicating variability between QFT-GIT results at baseline and after six months. Conclusion: It was concluded that the prevalence of tuberculosis infection was common among South African children who live with an adult with active tuberculosis. The agreement between QFT-GIT assay and TST for the diagnosis of latent tuberculosis in children was high. Although TST and QFT-GIT assays appeared comparable, QFT-GIT showed higher positivity rate amongst those contacts with reported household tuberculosis exposure compared to TST. The QFTGIT assay was a better indicator of the risk of M.tuberculosis infection than TST in a BCG-vaccinated population.