Publications by authors named "Jason Mwenda"

The emergence of SARS-CoV-2 variants has heightened concerns about vaccine efficacy, posing challenges in controlling the spread of COVID-19. As part of the COVID-19 Vaccine Effectiveness and Variants (COVVAR) study in Uganda, this study aimed to genotype and characterize SARS-CoV-2 variants in patients with COVID-19-like symptoms who tested positive on a real-time PCR. Amplicon deep sequencing was performed on 163 oropharyngeal/nasopharyngeal swabs collected from symptomatic patients.

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Post rotavirus vaccine introduction in Mozambique (September 2015), we documented a decline in rotavirus-associated diarrhoea and genotypes changes in our diarrhoeal surveillance spanning 2008-2021. This study aimed to perform whole-genome sequencing of rotavirus strains from 2009 to 2012 (pre-vaccine) and 2017-2018 (post-vaccine). Rotavirus strains previously detected by conventional PCR as G2P[4], G2P[6], G3P[4], G8P[4], G8P[6], and G9P[6] from children with moderate-to-severe and less-severe diarrhoea and without diarrhoea (healthy community controls) were sequenced using Illumina MiSeq platform and analysed using bioinformatics tools.

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  • The text discusses the impact of pneumococcal conjugate vaccines (PCVs), specifically PCV10 and PCV13, on invasive pneumococcal disease (IPD) globally, highlighting how these vaccines have reduced the prevalence of disease caused by vaccine-type serotypes after extensive use.
  • It describes the methodology of data collection from various surveillance sites, which aimed to evaluate IPD cases that occurred five years after the vaccines were implemented, focusing on different age groups for analysis.
  • Findings indicate significant differences in serotype distribution between PCV10 and PCV13 sites; notably, certain serotypes, such as 19A and serotype 3, were prevalent in specific age groups, signaling ongoing challenges in controlling
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Background: Rotavirus vaccines are moderately protective against illness in high mortality settings compared with low mortality settings. Vaccine effectiveness (VE) evaluations may clarify our understanding of these disparities, but estimates among key subpopulations and against rare outcomes are not available in many analyses due to sample size. We combined 25 datasets from test-negative design case-control evaluations in 24 countries that enrolled children with medically-attended diarrhea, laboratory-confirmed rotavirus stool testing, and documented vaccination status.

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Universal access to childhood vaccination is important to child health and sustainable development. Here we identify, at a fine spatial scale, under-immunized children and zero-dose children. Using Chad, as an example, the most recent nationally representative household survey that included recommended vaccine antigens was assembled.

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  • Ghana switched from the 2-dose Rotarix to the 3-dose Rotavac rotavirus vaccine in 2020 to improve cost-efficiency and reduce cold chain requirements in childhood immunization programs.
  • A study analyzed vaccination and diarrhea data from 2018 to 2022, finding that the uptake of rotavirus vaccines remained stable and there were no significant differences in vaccination coverage or outpatient department visits for diarrhea before and after the switch.
  • The transition to Rotavac provided expected benefits without negative impact, suggesting that such vaccine switches can be beneficial for other immunizations to lower costs and maintain health outcomes.
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Background: Monovalent rotavirus vaccine substantially reduced rotavirus disease burden after introduction (May 2014) in Madagascar. We examined the effectiveness and long-term impact on acute watery diarrhea and rotavirus-related hospitalizations among children <5 years old at two hospitals in Antananarivo, Madagascar (2010-2022).

Methods: We used a test-negative case-control design to estimate monovalent rotavirus vaccine effectiveness (VE) against laboratory-confirmed rotavirus hospitalizations among children age 6-23 months with documented vaccination status adjusted for year of symptom onset, rotavirus season, age group, nutritional status, and clinical severity.

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  • Enteric viruses are the main cause of diarrhea in children under 5, with rotavirus being a well-researched culprit in Mozambique, though other viruses lack data post-vaccine.
  • The study investigated the prevalence of norovirus GI and GII, adenovirus 40/41, astrovirus, and sapovirus in children with varying severity of diarrhea before and after the introduction of the rotavirus vaccine.
  • Results showed that all viruses, except norovirus GI, were detected more frequently after the vaccine's introduction, highlighting the importance of ongoing monitoring for these viruses to improve disease prevention strategies.
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Background: Mozambique was one of many African countries with limited testing capacity for SARS-CoV-2. Serosurveys, an alternative to estimate the real exposure to understand the epidemiology and transmission dynamics, have been scarce in Mozambique. Herein, we aimed to estimate the age-specific seroprevalence of SARS-CoV-2 in the general population of the Manhiça District, at four time points, for evaluating dynamics of exposure and the impact of vaccination.

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Introduction: Botswana had a resurgent diarrhea outbreak in 2018, mainly affecting children under five years old. Botswana introduced rotavirus vaccine (RotarixTM) into the national immunization programme in July 2012. Official rotavirus vaccine coverage estimates averaged 77.

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Although the introduction of rotavirus vaccines has substantially contributed to the reduction in rotavirus morbidity and mortality, concerns persist about the re-emergence of variant strains that might alter vaccine effectiveness in the long term. The G9 strains re-emerged in Africa during the mid-1990s and have more recently become predominant in some countries, such as Ghana and Zambia. In Rwanda, during the 2011 to 2015 routine surveillance period, G9P[8] persisted during both the pre- and post-vaccine periods.

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Rotavirus is the most common pathogen causing pediatric diarrhea and an important cause of morbidity and mortality in low- and middle-income countries. Previous evidence suggests that the introduction of rotavirus vaccines in national immunization schedules resulted in dramatic declines in disease burden but may also be changing the rotavirus genetic landscape and driving the emergence of new genotypes. We report genotype data of more than 16,000 rotavirus isolates from 40 countries participating in the Global Rotavirus Surveillance Network.

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  • Laboratories in the IB-VPD network must effectively identify the causes of pediatric bacterial meningitis through Gram stains and phenotypic methods, with data from the WHO's external quality assessments analyzed from 2014 to 2019.
  • Results showed that only 63% of sentinel site and national labs correctly identified pathogens in 2019, with earlier assessments indicating challenges in Gram staining and culture identification.
  • A strong quality management system is necessary to address performance gaps and to implement corrective measures for accurate pathogen detection.
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Background: A low-level risk of intussusception following rotavirus vaccination has been observed in some settings and may vary by vaccine type. We examined the association between RotaTeq vaccination and intussusception in low-income settings in a pooled analysis from 5 African countries that introduced RotaTeq into their national immunization program.

Methods: Active surveillance was conducted at 20 hospitals to identify intussusception cases.

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Mozambique introduced the rotavirus vaccine (Rotarix®; GlaxoSmithKline Biologicals, Rixensart, Belgium) in 2015, and since then, the Centro de Investigação em Saúde de Manhiça has been monitoring its impact on rotavirus-associated diarrhea and the trend of circulating strains, where G3P[8] was reported as the predominant strain after the vaccine introduction. Genotype G3 is among the most commonly detected Rotavirus strains in humans and animals, and herein, we report on the whole genome constellation of G3P[8] detected in two children (aged 18 months old) hospitalized with moderate-to-severe diarrhea at the Manhiça District Hospital. The two strains had a typical Wa-like genome constellation (I1-R1-C1-M1-A1-N1-T1-E1-H1) and shared 100% nucleotide (nt) and amino acid (aa) identities in 10 gene segments, except for VP6.

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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 G8P[4]. This study aimed to elucidate the entire genome and evolution of Rwandan G8P[4] strains.

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Background: Following the World Health Organization (WHO) recommendation, 38/47 countries have introduced rotavirus vaccines into the program of immunization in the WHO Regional Office for Africa (WHO/AFRO). Initially, two vaccines (Rotarix and Rotateq) were recommended and recently two additional vaccines (Rotavac and Rotasiil) have become available. However, the global supply challenges have increasingly forced some countries in Africa to switch vaccine products.

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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.

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Background: As of the end of 2021, twenty-four countries in the African meningitis belt have rolled out mass campaigns of MenAfriVac®, a meningococcal A conjugate vaccine (MACV) first introduced in 2010. Twelve have completed introduction of MACV into routine immunisation (RI) schedules. Although select post-campaign coverage data are published, no study currently comprehensively estimates MACV coverage from both routine and campaign sources in the meningitis belt across age, country, and time.

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The G2P[4] genotype is among the rotavirus strains that circulate commonly in humans. Several countries have reported its immediate upsurge after the introduction of rotavirus vaccination, raising concern about sub-optimal vaccine effectiveness against this genotype in the long term. This study aimed to gain insight into the evolution of post-vaccine Zambian G2P[4] group A rotavirus (RVA) strains and their overall genetic make-up by analysis of sequence alignments at the amino acid (AA) level.

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In 2009, the World Health Organization (WHO) established the Global Invasive Bacterial Vaccine Preventable Disease (IB-VPD) Surveillance Network (GISN) to monitor the global burden and aetiology of bacterial meningitis, pneumonia and sepsis caused by (Hi), (Nm) and (Sp).. The GISN established an external quality assessment (EQA) programme for the characterization of Hi, Nm and Sp by culture and diagnostic PCR.

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Côte d'Ivoire introduced rotavirus vaccine in March 2017. Rotavirus surveillance is conducted at Centre Hospitalier Universitaire de Yopougon in Abidjan, the capital city. Children <5 years of age are enrolled in rotavirus surveillance if admitted to the hospital with acute gastroenteritis.

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Introduction: Diarrhoea remains a leading cause of child morbidity and mortality. Systematically collected and analysed data on the aetiology of hospitalised diarrhoea in low-income and middle-income countries are needed to prioritise interventions.

Methods: We established the Global Pediatric Diarrhea Surveillance network, in which children under 5 years hospitalised with diarrhoea were enrolled at 33 sentinel surveillance hospitals in 28 low-income and middle-income countries.

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Background: Rotavirus infection is a significant cause of gastroenteritis in developing countries and, in severe cases even leads to death. The impact of rotavirus vaccine introduction in reducing the rotavirus disease burden in children was well known. The study was aimed to determine the prevalence and clinical characteristics of rotavirus gastroenteritis before the introduction of rotavirus vaccine into Nigeria's routine immunization program.

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Article Synopsis
  • The study assessed the impact of the Rotarix® rotavirus vaccine in Mozambique, focusing on its effect on hospitalizations due to childhood gastroenteritis after its introduction in September 2015.
  • Findings showed a significant decrease in the prevalence of acute gastroenteritis from 19% pre-vaccine to 10% post-vaccine, preventing 40% of expected cases overall and 84% of lab-confirmed rotavirus cases in infants.
  • The incidence of rotavirus was also drastically lower post-vaccination, with an 11.8-fold decrease, most notably in infants, highlighting the vaccine's important role in protecting vulnerable populations from severe diarrhea and related hospitalizations.
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