The Full Impact of Rotavirus Vaccines in Africa Has Yet to Be Realized.

Africa bears the brunt of diarrheal mortality globally. Rotavirus vaccination rates are high across the continent and demonstrate impact on diarrheal disease reduction. Nevertheless, there is room for significant improvement in managing rotavirus vaccine coverage, in access to recognized public services such as appropriate medical care, including oral rehydration therapy and improved water and sanitation.

Maintaining Momentum for Rotavirus Immunization in Africa during the COVID-19 Era: Report of the 13th African Rotavirus Symposium.

The 13th African Rotavirus Symposium was held as a virtual event hosted by the University of Nairobi, Kenya and The Kenya Paediatric Association on 3rd and 4th November 2021. This biennial event organized under the auspices of the African Rotavirus Network shapes the agenda for rotavirus research and prevention on the continent, attracting key international and regional opinion leaders, researchers, and public health scientists. The African Rotavirus Network is a regional network of institutions initially established in 1999, and now encompassing much of the diarrheal disease and rotavirus related research in Africa, in collaboration with the World Health Organization African Regional Office (WHO-AFRO), Ministries of Health, and other partners. Surges in SARS-CoV2 variants and concomitant travel restrictions limited the meeting to a webinar platform with invited scientific presentations and scientific presentations from selected abstracts. The scientific program covered updates on burden of diarrheal diseases including rotavirus, the genomic characterization of rotavirus strains pre- and post-rotavirus vaccine introduction, and data from clinical evaluation of new rotavirus vaccines in Africa. Finally, 42 of the 54 African countries have fully introduced rotavirus vaccination at the time of the meeting, including the two recently WHO pre-qualified vaccines from India. Nonetheless, the full benefit of rotavirus vaccination is yet to be realized in Africa where approximately 80% of the global burden of rotavirus mortality exists.

Estimating the cost of COVID-19 vaccine deployment and introduction in Ghana using the CVIC tool.

BACKGROUND: This study estimated cost of COVID-19 vaccine introduction and deployment in Ghana. METHODS: Using the WHO-UNICEF COVID-19 Vaccine Introduction and deployment Costing (CVIC) tool Ghana's Ministry of Health Technical Working Group for Health Technology Assessment (TWG-HTA) in collaboration with School of Public Health, University of Ghana, organized an initial two-day workshop that brought together partners to deliberate and agree on input parameters to populate the CVIC tool. A further 2-3 days validation with the Expanded Program of Immunization (EPI) and other partners to finalize the analysis was done. Three scenarios, with different combinations of vaccine products and delivery modalities, as well as time period were analyzed. The scenarios included AstraZeneca (40%), Johnson & Johnson (J&J) (30%), Moderna, Pfizer, and Sputnik V at 10% each; with primary schedule completed by second half of 2021 (Scenario 1); AstraZeneca (30%), J&J (40%), Moderna, Pfizer, and Sputnik V at 10% each with primary schedule completed by first half of 2022 (Scenario 2); and equal distribution (20%) among AstraZeneca, J&J, Moderna, Pfizer, and Sputnik V with primary schedule completed by second half of 2022 (Scenario 3). RESULTS: The estimated total cost of COVID-19 vaccination ranges between $348.7 and $436.1 million for the target population of 17.5 million. These translate into per person completed primary schedule cost of $20.9-$26.2 and per dose (including vaccine cost) of $10.5-$13.1. Again, per person completed primary schedule excluding vaccine cost was $4.5 and $4.6, thus per dose excluding vaccine also ranged from $2.2 - $2.3. The main cost driver was vaccine doses, including shipping, which accounts for between 78% and 83% of total cost. Further, an estimated 8,437-10,247 vaccinators (non-FTEs) would be required during 2021-2022 to vaccinate using a mix of delivery strategies, accounting for 8-10% of total cost. CONCLUSION: These findings provide the estimates to inform resource mobilization efforts by government and other partners.

Detection of Enterotoxigenic Escherichia coli in Rotavirus-Infected Ghanaian Children Diagnosed with Acute Gastroenteritis.

Diarrhea is a notable global health problem in several developing countries, especially in children. Prior to the introduction of the rotavirus vaccination program in Ghana, a surveillance study was conducted to investigate the prevalence of the disease caused by rotavirus in children. In this report, we re-used archival stool samples from the pre-vaccine surveillance study to provide information on prevalence of enterotoxigenic Escherichia coli in Ghanaian children. Re-analysis of the stool samples revealed co-infection of enterotoxigenic E. coli and rotavirus in 2% of the children whose samples were selected for this study. As Ghana is approaching 10 years post-implementation of the rotavirus vaccination program, the preliminary data presented in this report are a vital reference for subsequent studies aimed at ascertaining the effect of the vaccine on both rotavirus and enterotoxigenic E. coli.

Understanding Pediatric Norovirus Epidemiology: A Decade of Study among Ghanaian Children.

Understanding the epidemiology of human norovirus infection in children within Ghana and the entire sub-Saharan African region, where future norovirus vaccines would have the greatest impact, is essential. We analyzed 1337 diarrheic stool samples collected from children <5 years from January 2008 to December 2017 and found 485 (36.2%) shedding the virus. GII.4 (54.1%), GII.3 (7.7%), GII.6 (5.3%), GII.17 (4.7%), and GII.5 (4.7%) were the most common norovirus genotypes. Although norovirus GII.4 remained the predominant capsid genotype throughout the study period, an increase in GII.6 and GII.3 capsid genotypes was observed in 2013 and 2014, respectively. The severity of clinical illness in children infected with GII.4 norovirus strains was similar to illness caused by non-GII.4 strains. Since the epidemiology of norovirus changes rapidly, establishment of systematic surveillance within sentinel sites across the country would enhance the monitoring of circulating norovirus strains and allow continuous understanding of norovirus infection in Ghana.

Modeling of rotavirus transmission dynamics and impact of vaccination in Ghana.

BACKGROUND: Rotavirus incidence remains relatively high in low-income countries (LICs) compared to high-income countries (HICs) after vaccine introduction. Ghana introduced monovalent rotavirus vaccine in April 2012 and despite the high coverage, vaccine performance has been modest compared to developed countries. The predictors of low vaccine effectiveness in LICs are poorly understood, and the drivers of subnational heterogeneity in rotavirus vaccine impact are unknown. METHODS: We used mathematical models to investigate variations in rotavirus incidence in children <5 years old in Ghana. We fit models to surveillance and case-control data from three different hospitals: Korle-Bu Teaching Hospital in Accra, Komfo Anokye Teaching Hospital in Kumasi, and War Memorial Hospital in Navrongo. The models were fitted to both pre- and post-vaccine data to estimate parameters describing the transmission rate, waning of maternal immunity, and vaccine response rate. RESULTS: The seasonal pattern and age distribution of rotavirus cases varied among the three study sites in Ghana. Our model was able to capture the spatio-temporal variations in rotavirus incidence across the three sites and showed good agreement with the age distribution of observed cases. The rotavirus transmission rate was highest in Accra and lowest in Navrongo, while the estimated duration of maternal immunity was longer (~5 months) in Accra and Kumasi and shorter (~3 months) in Navrongo. The proportion of infants who responded to the vaccine was estimated to be high in Accra and Kumasi and low in Navrongo. CONCLUSIONS: Rotavirus vaccine impact varies within Ghana. A low vaccine response rate was estimated for Navrongo, where rotavirus is highly seasonal and incidence limited to a few months of the year. Our findings highlight the need to further explore the relationship between rotavirus seasonality, maternal immunity, and vaccine response rate to determine how they influence vaccine effectiveness and to develop strategies to improve vaccine impact.

Distribution of rotavirus genotypes in the postvaccine introduction era in Ashaiman, Greater Accra Region, Ghana, 2014-2016.

Group A Rotaviruses (RVAs) are the most important etiological agents of acute gastroenteritis (AGE) in children less than 5 years of age. Mortality resulting from RVA gastroenteritis is higher in developing countries than in developed ones, causing a huge public health burden in global regions like Africa and South-East Asia. This study reports RVA genotypes detected in Ashaiman, Greater Accra Region, Ghana, in the postvaccine introduction era for the period 2014-2016. Stool samples were collected from children less than 5 years of age who visited Ashaiman Polyclinic with AGE from November 2014 to May 2015 and from December 2015 to June 2016. The samples were tested by enzyme immunoassay (EIA), and one-step multiplex reverse transcription polymerase chain reaction was performed on the EIA positive samples for gel-based binomial genotyping. Of the 369 stool samples collected from children with AGE, 145 (39%) tested positive by EIA. Five VP7 (G1, G3, G9, G10, and G12) and three VP4 (P[4], P[6] and P[8]) genotypes were detected. Eight G/P combinations were identified of which, G3P[6], G12P[8], G1P[8], and G9P[4] were the most prevalent and responsible for 93 (68%) of the AGE cases, and seven mixed-types were detected which represented 8% of the RVA cases. High prevalence, diversity, and mixed-types of RVAs were detected from Ashaiman with the emergence of unusual genotypes.

Rotavirus Vaccine Take in Infants Is Associated With Secretor Status.

Rotaviruses bind to enterocytes in a genotype-specific manner via histo-blood group antigens (HBGAs), which are also detectable in saliva. We evaluated antirotavirus immunoglobulin A seroconversion ('vaccine take") among 166 Ghanaian infants after 2-3 doses of G1P[8] rotavirus vaccine during a vaccine trial, by HBGA status from saliva collected at age 4.1 years. Only secretor status was associated with seroconversion: 41% seroconversion for secretors vs 13% for nonsecretors; relative risk, 3.2 (95% confidence interval, 1.2-8.1; P = .016). Neither Lewis antigen nor salivary antigen blood type was associated with seroconversion. Likelihood of "take" for any particular rotavirus vaccine may differ across populations based on HBGAs.

Identification of Amino Acid Substitutions Within the VP7 Genes of G2 Rotavirus Strains in Ghana.

We used the dideoxynucleotide chain termination method to determine the strains of nine non-typeable rotavirus enzyme immunoassay-positive samples, which were identified as G2. We detected nucleotide changes in the primer-binding region and amino acid substitutions within the VP7 protein of the G2 rotavirus strains. Genotyping primers need to be updated regularly.

Detection of Dengue Virus among Children with Suspected Malaria, Accra, Ghana.

We report new molecular evidence of locally acquired dengue virus infections in Ghana. We detected dengue viral RNA among children with suspected malaria by using a multipathogen real-time PCR. Subsequent sequence analysis revealed a close relationship with dengue virus serotype 2, which was implicated in a 2016 outbreak in Burkina Faso.

Urban sanitation coverage and environmental fecal contamination: Links between the household and public environments of Accra, Ghana.

Exposure to fecal contamination in public areas, especially in dense, urban environments, may significantly contribute to enteric infection risk. This study examined associations between sanitation and fecal contamination in public environments in four low-income neighborhoods in Accra, Ghana. Soil (n = 72) and open drain (n = 90) samples were tested for E. coli, adenovirus, and norovirus. Sanitation facilities in surveyed households (n = 793) were categorized by onsite fecal sludge containment ("contained" vs. "uncontained") using previous Joint Monitoring Program infrastructure guidelines. Most sanitation facilities were shared by multiple households. Associations between spatial clustering of household sanitation coverage and fecal contamination were examined, controlling for neighborhood and population density (measured as enumeration areas in the 2010 census and spatially matched to sample locations). E. coli concentrations in drains within 50m of clusters of contained household sanitation were more than 3 log-units lower than those outside of clusters. Further, although results were not always statistically significant, E. coli concentrations in drains showed consistent trends with household sanitation coverage clusters: concentrations were lower in or near clusters of high coverage of household sanitation facilities-especially contained facilities-and vice versa. Virus detection in drains and E. coli concentrations in soil were not significantly associated with clustering of any type of household sanitation and did not exhibit consistent trends. Population density alone was not significantly associated with any of the fecal contamination outcomes by itself and was a significant, yet inconsistent, effect modifier of the association between sanitation clusters and E. coli concentrations. These findings suggest clustering of contained household sanitation, even when shared, may be associated with lower levels of fecal contamination within drains in the immediate public domain. Further research is needed to better quantify these relationships and examine impacts on health.

Rotavirus strain distribution in Ghana pre- and post- rotavirus vaccine introduction.

BACKGROUND: Ghana introduced the monovalent rotavirus vaccine (Rotarix) into its national paediatric vaccination programme in May2012. Vaccine introduction was initiated nationwide and achieved >85% coverage within a few months. Rotavirus strain distribution pre- and post-RV vaccine introduction is reported. METHODS: Stool samples were collected from diarrhoeic children <5 years of age hospitalized between 2009 and 2016 at sentinel sites across Ghana and analyzed for the presence of group A rotavirus by enzyme immunoassay. Rotavirus strains were characterized by RT-PCR and sequencing. RESULTS: A total of 1363 rotavirus EIA-positive samples were subjected to molecular characterization. These were made up of 823 (60.4%) and 540 (39.6%) samples from the pre- and post-vaccine periods respectively. Rotavirus VP7 genotypes G1, G2 and G3, and VP4 genotypes P[6] and P[8] constituted more than 65% of circulating G and P types in the pre-vaccine period. The common strains detected were G1P[8] (20%), G3P[6] (9.2%) and G2P[6] (4.9%). During the post-vaccine period, G12, G1 and G10 genotypes, constituted more than 65% of the VP7 genotypes whilst P[6] and P[8] made up more than 75% of the VP4 genotypes. The predominant circulating strains were G12P[8] (26%), G10P[6] (10%) G3P[6] (8.1%) and G1P[8] (8.0%). We also observed the emergence of the unusual rotavirus strain G9P[4] during this period. CONCLUSION: Rotavirus G1P[8], the major strain in circulation during the pre-vaccination era, was replaced by G12P[8] as the most predominant strain after vaccine introduction. This strain replacement could be temporary and unrelated to vaccine introduction since an increase in G12 was observed in countries yet to introduce the rotavirus vaccine in West Africa. A continuous surveillance programme in the post-vaccine era is necessary for the monitoring of circulating rotavirus strains and the detection of unusual/emerging genotypes.

Reaching every child with rotavirus vaccine: Report from the 10th African rotavirus symposium held in Bamako, Mali.

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.

Detection of the first G6P[14] human rotavirus strain in an infant with diarrhoea in Ghana.

BACKGROUND: Rotaviruses with G6P[14] specificity are mostly isolated in cattle and have been established as a rare cause of gastroenteritis in humans. This study reports the first detection of G6P[14] rotavirus strain in Ghana from the stool of an infant during a hospital-based rotavirus surveillance study in 2010. METHODS: Viral RNA was extracted and rotavirus VP7 and VP4 genes amplified by one step RT-PCR using gene-specific primers. The DNA was purified, sequenced and genotypes determined using BLAST and RotaC v2.0. Phylogenetic tree was constructed using maximum likelihood method in MEGA v6.06 software and statistically supported by bootstrapping with 1000 replicates. Phylogenetic distances were calculated using the Kimura-2 parameter model. RESULTS: The study strain, GHA-M0084/2010 was characterised as G6P[14]. The VP7 gene of the Ghanaian strain clustered in G6 lineage-III together with artiodactyl and human rotavirus (HRV) strains. It exhibited the highest nucleotide (88.1 %) and amino acid (86.9 %) sequence identity with Belgian HRV strain, B10925. The VP8* fragment of the VP4 gene was closely related to HRV strains detected in France, Italy, Spain and Belgium. It exhibited the strongest nucleotide sequence identity (87.9 %) with HRV strains, PA169 and PR/1300 (Italy) and the strongest amino acid sequence identity (89.3 %) with HRV strain R2775/FRA/07 (France). CONCLUSION: The study reports the first detection of G6P[14] HRV strain in an infant in Ghana. The detection of G6P[14], an unusual strain pre-vaccine introduction in Ghana, suggests a potential compromise of vaccine effectiveness and indicates the necessity for continuous surveillance in the post vaccine era.

Genomic constellation and evolution of Ghanaian G2P[4] rotavirus strains from a global perspective.

Understanding of the genetic diversity and evolution of Rotavirus A (RVA) strains, a common cause of severe diarrhoea in children, needs to be based on the analysis at the whole genome level in the vaccine era. This study sequenced the whole genomes of six representative G2P[4] strains detected in Ghana from 2008 to 2013, and analysed them phylogenetically with a global collection of G2P[4] strains and African non-G2P[4] DS-1-like strains. The genotype constellation of the study strains was G2-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2. Strains from the same season were highly identical across the whole genome while strains from different seasons were more divergent from each other. The VP7, VP4, VP2, NSP1, and NSP5 genes belonged to lineage IVa; the VP6, VP1, NSP2, and NSP3 genes belonged to lineage V, and all these genes evolved in the same fashion as the global strains. In the NSP4 gene, lineages V (2008) and X (2009) were replaced by VI (2012/2013) whereas in the VP3 gene, lineage V (2008/2009) was replaced by VII (2012/2013) and these replacements coincided with the vaccine introduction period (2012). The evolutionary rate of the NSP4 gene was 1.2×10-3 substitutions/site/year and was rather comparable to that of the remaining 10 genes. The multiple NSP4 lineages were explained by intra-genotype reassortment with co-circulating African human DS-1-like strains bearing G2[6], G3P[6], G6[6] and G8. There was no explicit evidence of the contribution of animal RVA strains to the genome of the Ghanaian G2P[4] strains. In summary, this study revealed the dynamic evolution of the G2P[4] strains through intra-genotype reassortment events leading to African specific lineages such IX and X in the NSP4 gene. So far, there was no evidence of a recent direct involvement of animal RVA genes in the genome diversity of African G2P[4] strains.

Norovirus Epidemiology in Africa: A Review.

Norovirus (NoV) is recognised as a leading cause of gastroenteritis worldwide across all age groups. The prevalence and diversity of NoVs in many African countries is still unknown, although early sero-prevalence studies indicated widespread early infection. Reports on NoVs in Africa vary widely in terms of study duration, population groups and size, inclusion of asymptomatic controls, as well as genotyping information. This review provides an estimate of NoV prevalence and distribution of genotypes of NoVs in Africa. Inclusion criteria for the review were study duration of at least 6 months, population size of >50 and diagnosis by RT-PCR. As regions used for genotyping varied, or genotyping was not always performed, this was not considered as an inclusion criteria. A literature search containing the terms norovirus+Africa yielded 74 publications. Of these 19 studies from 14 out of the 54 countries in Africa met the inclusion criteria. Data from studies not meeting the inclusion criteria, based on sample size or short duration, were included as discussion points. The majority of studies published focused on children, under five years of age, hospitalised with acute gastroenteritis. The mean overall prevalence was 13.5% (range 0.8-25.5%) in children with gastroenteritis and 9.7% (range 7-31%) in asymptomatic controls, where tested. NoV GII.4 was the predominant genotype identified in most of the studies that presented genotyping data. Other prevalent genotypes detected included GII.3 and GII.6. In conclusion, NoV is a common pathogen in children with diarrhoea in Africa, with considerable carriage in asymptomatic children. There is however, a paucity of data on NoV infection in adults.

Identification of OP354-like human rotavirus strains with subtype P[8]b in Ghanaian children with diarrhoea.

BACKGROUND: Rotaviruses with the P[8] genotype have been associated with majority of infections. Recent improvements in molecular diagnostics have delineated the P[8] genotype into P[8]a and P[8]b subtypes. P[8]a is the previously known P[8] genotype which is common whilst P[8]b subtype also known as OP354-like strain is genetically distinct, rarely detected and reported from a few countries. In a previous study, the P-types could not be determined for 80 RVA-positive samples by conventional RT-PCR genotyping methods with the recommended pool of P-genotype specific primers used in the WHO Regional Rotavirus Reference Laboratory in Ghana. The present study employed sequence-dependent cDNA amplification method to genotype previously non-typeable P-types. METHODS: Viral RNAs were extracted and rotavirus VP4 genes amplified by one step RT-PCR using gene specific primers. PCR amplicons were purified, sequenced and sequences aligned with cognate gene sequences available in GenBank using the ClustalW algorithm. Phylogenetic analysis was performed using the Neighbour-Joining method in MEGA v6.06 software. Phylogenetic tree was statistically supported by bootstrapping with 1000 replicates, and distances calculated using the Kimura-2 parameter model. RESULTS: Of the 80 RVA-positive samples, 57 were successfully sequenced and characterized. Forty-eight of these were identified as P[8] strains of which 5 were characterized as the rare P[8]b subtype. Phylogenetic analysis of the VP8* fragment of the VP4 genes of these P[8]b strains revealed a close relationship with prototype OP354-like P[8]b strain and P[8]b strains of Russian and South African P[8]b origin. CONCLUSION: The study highlights the importance of regularly updating the primers employed for molecular typing of rotaviruses.

Rotavirus Infection in Children with Diarrhea at Korle-Bu Teaching Hospital, Ghana.

Human rotavirus infection was studied over a 13-month period (January 2004 to January 2005) in children <5 years of age admitted with severe diarrhea at the Korle-Bu Teaching Hospital in Accra, Ghana. During this period, 206 hospitalizations for diarrhea were recorded, with 34.0% (70/206) being positive for rotavirus infection. Infection occurred throughout the year, with peak rotavirus infection occurring during the month of March. Hospitalization associated with rotaviruses was most common in the 6-8 month age group. The case fatality rate of rotavirus infection was 2.9% (2/70) and occurred in children <12 months of age. Four rotavirus VP7 genotypes (G1, G2, G3, and G9) were detected. The predominant genotypes were G2 (22.9%), G1 (17.1%), G9 (17.1%) and G3 (12.9%). Mixed G types were also detected. The predominant VP4 genotypes (P types) were P[6] (38.6%), P[8] (21.4%), P[4] (4.3%) and P[9] (1.4%). The predominant rotavirus strains infecting children in Accra were G9P[6] (10.0%) and G1P[8] (8.6%). Strains with unusual genotypes such as G2P[8] and G(2/3)P[6] were also detected.

Immunolocalization of the 29 kDa Schistosoma haematobium species-specific antigen: a potential diagnostic marker for urinary schistosomiasis.

BACKGROUND: The 29 kDa Schistosoma haematobium species-specific antigen (ShSSA) is of remarkable interest in the diagnosis of urinary schistosomiasis although it had not been fully characterized. METHOD: To determine the biological importance of ShSSA in S. haematobium and pathogenesis of the disease, we immunolocalized ShSSA in schistosome eggshells, miracidia and adult worm sections using indirect fluorescent antibody test (IFAT). RESULTS: ShSSA was strongly immunolocalized in the schistosome eggshells, selective regions of the miracidia body and walls of internal organs such as oviduct, ovary, vitelline duct and gut of the adult worm. CONCLUSION: The strong immunolocalization of ShSSA in schistosome eggshells and adult worm internal organs suggests that the antigens involved in the pathogenesis of urinary schistosomiasis could have originated from the eggs and adult worms of the parasite. The findings also indicate that ShSSA may play a mechanical protective role in the survival of the parasite.