The African Rotavirus Network organised the 12th African Rotavirus Symposium (ARS) from 30 July to 1 August 2019 in Johannesburg, South Africa. The symposium theme “A decade of rotavirus vaccination ...in Africa - Saving lives and changing the face of diarrhoeal diseases”, included sessions aimed at sharing ideas and expertise on prevention and control of diarrhoeal disease in Africa. Inter alia, the delegates reviewed global and regional epidemiological trends on rotavirus diarrhoea, progress and experiences on rotavirus vaccine introduction, including vaccine safety monitoring and impact in Africa, scientific advances in developing newer rotavirus vaccines, surveillance and research on other diarrhoeal pathogens, and providing an enabling environment for networking. Importantly, the 12th ARS served to commemorate the 20th anniversary of the African Rotavirus Network (AfrRN) coinciding with the 50th anniversary of the South African Medical Research Council.
Four oral, live-attenuated rotavirus vaccines are currently prequalified by the WHO (Rotarix, RotaTeq, Rotavac and RotaSiil). African countries utilising rotavirus vaccines in routine national immunisation programmes are realising their effectiveness and impact on diarrhoeal disease morbidity. An ~40% reduction in hospitalisations of <5-year-olds with acute gastroenteritis following rotavirus vaccine introduction, was reported between 2006 and 2018 in 92,000 children from the WHO-coordinated African Rotavirus Surveillance Network (AfrRSN) comprising 33 Member States. This was corroborated by a meta-analysis of published data, sourced from January 2000 to August 2018 that reported substantial reductions in rotavirus hospitalisations in countries using rotavirus vaccines. However, it was highlighted that the transition of some countries from Gavi-eligibility and vaccine supply shortfalls present significant challenges to achieving the full impact of rotavirus immunization in Africa. The wide diversity of rotavirus genotypes continues in Africa, with variation observed both geographically and temporally. There is currently no evidence to suggest that the emergence of rotavirus strains not included in the current vaccines do escape vaccine-induced immunity.
•10th African Rotavirus Symposium, Bamako, Mali, 1–2 June 2016.•Reaching every child in Africa with rotavirus vaccines.•Global gathering of rotavirus researchers, scientists, and policy-makers.
The ...Center for Vaccine Development – Mali (CVD – Mali), the World Health Organization’s regional office in Africa (WHO/AFRO), and the CVD at the University of Maryland School of Medicine hosted the 10th African Rotavirus Symposium in Bamako, Mali on 1–2 June 2016. The symposium is coordinated by WHO/AFRO, the Regional Rotavirus Reference Laboratories, and the African Rotavirus Network (ARN), with support from the Bill & Melinda Gates Foundation. The event brings together leading rotavirus researchers, scientists, and policy-makers from across Africa and the world. Over 150 participants, from 31 countries, including 27 in Africa, joined forces to address the theme “Reaching Every Child in Africa with Rotavirus Vaccines.” This symposium, the first in francophone Africa, occurred at an unprecedented time when 33 African countries had introduced rotavirus vaccines into their national immunization programs. The symposium concluded with a Call to Action to introduce rotavirus vaccines in the 21 remaining African countries, to increase access in countries with existing vaccination programs, and to continue surveillance and research on rotavirus and other diarrheal diseases.
Highlights ► We have conducted a systematic review of rotavirus strain diversity in India over three decades. ► Strain diversity in South east Asia is high with novel strains, newly emerging strains ...and zoonotic strains in circulation. ► Strains differ across time intervals, but also regionally across the region during the same time period.
Rotavirus A (RVA) exhibits a wide genotype diversity globally. Little is known about the genetic composition of genotype P6 from Africa. This study investigated possible evolutionary mechanisms ...leading to genetic diversity of genotype P6 VP4 sequences.
Phylogenetic analyses on 167 P6 VP4 full-length sequences were conducted, which included six porcine-origin sequences. Of the 167 sequences, 57 were newly acquired through whole genome sequencing as part of this study. The other 110 sequences were all publicly-available global P6 VP4 full-length sequences downloaded from GenBank. The strength of association between the phenotypic features and the phylogeny was also determined.
A number of reassortment and mixed infections of RVA genotype P6 strains were observed in this study. Phylogenetic analyses demostrated the extensive genetic diversity that exists among human P6 strains, porcine-like strains, their concomitant clades/subclades and estimated that P6 VP4 gene has a higher substitution rate with the mean of 1.05E-3 substitutions/site/year. Further, the phylogenetic analyses indicated that genotype P6 strains were endemic in Africa, characterised by an extensive genetic diversity and long-time local evolution of the viruses. This was also supported by phylogeographic clustering and G-genotype clustering of the P6 strains when Bayesian Tip-association Significance testing (BaTS) was applied, clearly supporting that the viruses evolved locally in Africa instead of spatial mixing among different regions.
Overall, the results demonstrated that multiple mechanisms such as reassortment events, various mutations and possibly interspecies transmission account for the enormous diversity of genotype P6 strains in Africa. These findings highlight the need for continued global surveillance of rotavirus diversity.
•Mechanisms leading to genetic diversity of the African rotavirus P6 strains were investigated.•Phylogenetic analysis provided evidence that P6 is endemic in Africa.•The extensive genetic diversity that exists among P6 strains was highlighted.•The need for continued surveillance of rotavirus diversity was highlighted.•The potential negative impact on the effectiveness of current rotavirus vaccines was highlighted.
Objective
Modified texture food (MTF), especially pureed is associated with a high prevalence of under-nutrition and weight loss among older adults in long term care (LTC); however, this may be ...confounded by other factors such as dependence in eating. This study examined if the prescription of MTF as compared to regular texture food is associated with malnutrition risk in residents of LTC homes when diverse relevant resident and home-level covariates are considered.
Design
Making the Most of Mealtimes (M3) is a cross-sectional multi-site study.
Setting
32 LTC homes in four Canadian provinces.
Participants
Regular (n= 337) and modified texture food consumers (minced n= 139; pureed n= 68).
Measurements
Malnutrition risk was determined using the Mini Nutritional Assessment short-form (MNA-SF) score. The use of MTFs, and resident and site characteristics were identified from health records, observations, and standardized assessments. Hierarchical linear regression analyses, accounting for clustering, were performed to determine if the prescription of MTFs is associated with malnutrition risk while controlling for important covariates, such as eating assistance.
Results
Prescription of minced food F(1, 382)=5.01, p=0.03, as well as pureed food F(1, 279)=4.95, p=0.03, were both significantly associated with malnutrition risk among residents. After adjusting for age and sex, other significant covariates were: use of oral nutritional supplements, eating challenges (e.g., spitting food out of mouth), poor oral health, and cognitive impairment.
Conclusions
Prescription of minced or pureed foods was significantly associated with the risk of malnutrition among residents living in LTC facilities while adjusting for other covariates. Further work needs to consider improving the nutrient density and sensory appeal of MTFs and target modifiable covariates.
Africa has a high level of genetic diversity of rotavirus strains, which is suggested to be a possible reason contributing to the suboptimal effectiveness of rotavirus vaccines in this region. One ...strain that contributes to this rotavirus diversity in Africa is the G8P4. This study aimed to elucidate the entire genome and evolution of Rwandan G8P4 strains. Illumina sequencing was performed for twenty-one Rwandan G8P4 rotavirus strains. Twenty of the Rwandan G8P4 strains had a pure DS-1-like genotype constellation, and one strain had a reassortant genotype constellation. Notable radical amino acid differences were observed at the neutralization sites when compared with cognate regions in vaccine strains potentially playing a role in neutralization escape. Phylogenetic analysis revealed that the closest relationship was with East African human group A rotavirus (RVA) strains for five of the genome segments. Two genome sequences of the NSP4 genome segment were closely related to bovine members of the DS-1-like family. Fourteen VP1 and eleven VP3 sequences had the closest relationships with the RotaTeq™ vaccine WC3 bovine genes. These findings suggest that the evolution of VP1 and VP3 might have resulted from reassortment events with RotaTeq™ vaccine WC3 bovine genes. The close phylogenetic relationship with East African G8P4 strains from Kenya and Uganda suggests co-circulation in these countries. These findings highlight the need for continued whole-genomic surveillance to elucidate the evolution of G8P4 strains, especially after the introduction of rotavirus vaccination.
Abstract
Typhoid fever and other invasive salmonelloses remain a major public health concern, primarily in low- and middle-income countries in Asia and Africa, where transmission occurs through ...contaminated food or water. However, recent developments in research, policy, and implementation offer newfound optimism for prevention and control. Now, more than ever, a coordinated and multisectoral global response is needed. To chart the course to meet the challenges ahead, the Coalition against Typhoid, housed at the Sabin Vaccine Institute, virtually organized the 12th International Conference on Typhoid and Other Invasive Salmonelloses from December 7 to 9, 2021. This commentary provides an overview of the conference's significant findings, highlighting barriers and opportunities for prevention and control. Topics covered include diagnostics advancements, improved data methodologies for a better understanding of the disease burden, the incorporation of environmental surveillance and genomics, the threat of drug resistance, and the use of typhoid conjugate vaccines alongside other integrated solutions.
To strengthen the collective response against typhoid, the Coalition against Typhoid organized the 12th International Conference on Typhoid and Other Invasive Salmonelloses in 2021. This conference brought together researchers, advocates and policymakers aiming to enhance the fight against typhoid. This article describes the topics and research featured at the conference.
Highlights ► We characterized rotaviruses detected in a trial of a rotavirus vaccine in Malawi. ► We used nucleotide sequencing, RNA–RNA hybridization and phylogenetic analyses. ► The rotaviruses in ...Malawi were genetically similar to rotaviruses from elsewhere. ► Lower vaccine efficacy in Malawi is unlikely caused by rotavirus strain diversity.
An estimated 215,000 children died of rotavirus infections in 2013, accounting for 37% of diarrhea-related deaths worldwide, 92% of which occurred in low and lower-middle income countries. Since 2009 ...the World Health Organization (WHO) recommends the use of rotavirus vaccines in all national immunization programs. This review compares rotavirus vaccine (RV) introductions and vaccine coverage by region, country income status and Gavi-eligibility from 2006-2016. Gross National Income data from the World Bank and surviving infant population from United Nations Population Division was obtained for 2016. Data from WHO were collected on rotavirus vaccine coverage, national immunization schedules, and new vaccine introductions for 2016 while estimated rotavirus deaths were collected for 2013, the last year of available WHO data. As of December 2016, the majority of countries (57%, 110/194) had not introduced universal rotavirus vaccine despite WHO's 2009 recommendation to do so. Countries in the WHO African region had the greatest proportion of introductions (37%, 31/84) by December 2016 and a great majority of these (77%, 24/31) were supported by new vaccine introduction (NVI) grants from Gavi. Almost half (48%) of global introductions were in low and lower-middle income Gavi-eligible and Gavi-graduating countries. Conversely, countries in the Southeast Asia WHO region and those not eligible for Gavi NVI support have been slow to introduce rotavirus vaccine. High-income countries, on average, had poorer rotavirus vaccine coverage compared to low and lower-middle income countries. The over-representation of African countries within the Gavi subset and high estimated rotavirus deaths in these African countries, likely explains why introduction efforts have been focused in this region. While much progress has been made with the integration and implementation of rotavirus vaccine into national immunization programs, 110 countries representing 69% of the global birth cohort had yet to introduce the vaccine by December 2016.
Background. The recommended schedule for receipt of 2-dose human rotavirus vaccine (HRV) coincides with receipt of the first and second doses of diphtheria, pertussis, and tetanus vaccine (ie, 6 and ...10 weeks of age, respectively). Alternative schedules and additional doses of HRV have been proposed and may improve vaccine performance in low-income countries. Methods. In this randomized trial in rural Ghana, HRV was administered at ages 6 and 10 weeks (group 1), 10 and 14 weeks (group 2), or 6, 10, and 14 weeks (group 3). We compared serum antirotavirus immunoglobulin A (IgA) seroconversion (≥20 U/mL) and geometric mean concentrations (GMCs) between group 1 and groups 2 and 3. Results. Ninety-three percent of participants (424 of 456) completed the study per protocol. In groups 1, 2, and 3, the IgA seroconversion frequencies among participants with IgA levels of <20 U/mL at baseline were 28.9%, 37.4%, and 43.4%, respectively (group 1 vs group 3, P = .014; group 1 vs group 2, P = .163). Postvaccination IgA GMCs were 22.1 U/mL, 26.5 U/mL, and 32.6 U/mL in groups 1, 2, and 3, respectively (group 1 vs group 3, P = .038; group 1 vs group 2, P = .304). Conclusions. A third dose of HRV resulted in increased seroconversion frequencies and GMCs, compared with 2 doses administered at 6 and 10 weeks of age. Since there is no correlate of protection, a postmarketing effectiveness study is required to determine whether the improvement in immune response translates into a public health benefit in low-income countries. Clinical Trials Registration. NCT015751.
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