Rotavirus vaccination within the South African Expanded Programme on Immunisation
ABSTRACT Diarrhoeal diseases are ranked the third major cause of childhood mortality in South African children less than 5years, where the majority of deaths are among black children. Acute severe dehydrating rotavirus diarrhoea remains an important contributor towards childhood mortality and morbidity and has been well documented in South Africa. As the preventive strategy to control rotavirus diarrhoea, South Africa became the first country in the WHO African Region to adopt the rotavirus vaccine in the national childhood immunisation programme in August 2009. The rotavirus vaccine in use, Rotarix(®), GSK Biologicals, is given at 6 and 14weeks of age, along with other vaccines as part of Expanded Programme on Immunisation (EPI). Studies which facilitated the introduction of rotavirus vaccine in South Africa included the burden of rotavirus disease and strain surveillance, economic burden of rotavirus infection and clinical trials to assess the safety and efficacy of vaccine candidates. This paper reviews the epidemiology of rotavirus in South Africa, outlines some of the steps followed to introduce rotavirus vaccine in the EPI, and highlights the early positive impact of vaccination in reducing the rotavirus burden of disease based on the post-marketing surveillance studies at Dr George Mukhari hospital, a sentinel site at University of Limpopo teaching hospital in Pretoria, South Africa, which has conducted rotavirus surveillance for >20years.
- SourceAvailable from: Rashi Gautam
[Show abstract] [Hide abstract]
- ", United States ) , have been licensed in more than 100 6 countries and are being introduced into routine immunization programs in the United States and other 7 countries in Latin America , Europe , Africa and Asia ( Armah et al . , 2010 ; Benhafid et al . , 2012 ; Cunliffe 8 et al . , 2012 ; Madhi et al . , 2012 ; Ruiz - Palacios et al . , 2006 ; Seheri et al . , 2012 ; Vesikari et al . , 2007a ; 9 Vesikari et al . , 2007b ) . Countries considering using these vaccines to reduce RVA disease have 10 introduced strain surveillance programs to provide strain prevalence data in the pre - vaccine era and to 11 judge the impact of the vaccine after introduction . When these new vaccines become widely used "
ABSTRACT: The current two-step VP7 and VP4 genotyping RT-PCR assays for rotaviruses have been linked consistently to genotyping failure in an estimated 30% of RVA positive samples worldwide. We have developed a VP7 and VP4 multiplexed one-step genotyping assays using updated primers generated from contemporary VP7 and VP4 sequences. To determine assay specificity and sensitivity, 17 reference virus strains, 6 non-target gastroenteritis viruses and 725 clinical samples carrying the most common VP7 (G1, G2, G3, G4, G9, and G12) and VP4 (P, P, P, P and P) genotypes were tested in this study. All reference RVA strain targets yielded amplicons of the expected sizes and non-target genotypes and gastroenteritis viruses were not detected by either assay. Out of the 725 clinical samples tested, the VP7 and VP4 assays were able to assigned specific genotypes to 711 (98.1%) and 714 (98.5%), respectively. The remaining unassigned samples were re-tested for RVA antigen using EIA and qRT-PCR assays and all were found to be negative. The overall specificity, sensitivity and limit of detection of the VP7 assay were in the ranges of 99.0-100%, 94.0-100% and 8.6×10(1) - 8.6×10(2) copies of RNA/reaction, respectively. For the VP4 assay, the overall specificity, sensitivity and limit of detection assay were in the ranges of 100%, 94.0-100% and ≤ 1 - 8.6×10(2) copies of RNA/reaction, respectively. Here we report two highly robust, accurate, efficient, affordable and documentable gel-based genotyping systems which are capable of genotyping 97.8% of the six common VP7 and 98.3% of the five common VP4 genotypes of RVA strains which are responsible for approximately 88.2% of all RVA infections worldwide. Copyright © 2015. Published by Elsevier B.V.Journal of virological methods 07/2015; DOI:10.1016/j.jviromet.2015.07.012 · 1.88 Impact Factor
[Show abstract] [Hide abstract]
- "With the effective implementation of these two RV vaccines in both developed and developing countries, the morbidity and mortality rates associated with RV disease have dramatically declined (Fernandes et al., 2014; Msimang et al., 2013; Seheri et al., 2012; Vesikari et al., 2013; Walker et al., 2013). In Africa, data from South Africa showed a significant delay in the RV season by up to 8 weeks when comparing pre-and post-vaccination parameters in some settings (Seheri et al., 2012). "
ABSTRACT: Group A rotaviruses (RVA) are among the main global causes of severe diarrhea in children under the age of 5years. Strain diversity, mixed infections and untypeable RVA strains are frequently reported in Africa. We analysed rotavirus-positive human stool samples (n=13) obtained from hospitalised children under the age of 5years who presented with acute gastroenteritis at sentinel hospital sites in six African countries, as well as bovine and porcine stool samples (n=1 each), to gain insights into rotavirus diversity and evolution. Polyacrylamide gel electrophoresis (PAGE) analysis and genotyping with G-(VP7) and P-specific (VP4) typing primers suggested that 13 of the 15 samples contained more than 11 segments and/or mixed G/P genotypes. Full-length amplicons for each segment were generated using RVA-specific primers and sequenced using the Ion Torrent and/or Illumina MiSeq next-generation sequencing platforms. Sequencing detected at least one segment in each sample for which duplicate sequences, often having distinct genotypes, existed. This supported and extended the PAGE and RT-PCR genotyping findings that suggested these samples were collected from individuals that had mixed rotavirus infections. The study reports the first porcine (MRC-DPRU1567) and bovine (MRC-DPRU3010) mixed infections. We also report a unique genome segment 9 (VP7), whose G9 genotype belongs to lineage VI and clusters with porcine reference strains. Previously, African G9 strains have all been in lineage III. Furthermore, additional RVA segments isolated from humans have a clear evolutionary relationship with porcine, bovine and ovine rotavirus sequences, indicating relatively recent interspecies transmission and reassortment. Thus, multiple RVA strains from sub-Saharan Africa are infecting mammalian hosts with unpredictable variations in their gene segment combinations. Whole-genome sequence analyses of mixed RVA strains underscore the considerable diversity of rotavirus sequences and genome segment combinations that result from a complex evolutionary history involving multiple host species. Copyright © 2015. Published by Elsevier B.V.Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases 02/2015; 31. DOI:10.1016/j.meegid.2015.02.011 · 3.26 Impact Factor
- Vaccine 09/2012; 30 Suppl 3:C1-2. DOI:10.1016/j.vaccine.2012.06.094 · 3.49 Impact Factor