Share research - Vaccines

Exploring the relationship between environmental enteric dysfunction and oral vaccine responses

shareadmin — Fri, 31 May 2019 14:39:53 +0000

This paper discusses the links between environmental enteric dysfunction and oral vaccine responses. It was conducted by Church et al. (2018) and published in Future Microbiology. This is a crucial area of research as underperformance of oral vaccines in low-income countries has been partly attributed to environmental enteric dysfunction (EED) – a subclinical disorder of small intestinal structure and function among children living in poverty. Church et al. review 8 studies exploring EED and oral vaccine responses. Four studies reported a negative association between EED and oral vaccine responses; two showed no significant association; and two described a positive correlation. The authors conclude that the current evidence is therefore insufficient to determine the nature of the relationship between EED and oral vaccine underperformance.

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Neonatal vitamin A supplementation and immune responses to oral polio vaccine in Zimbabwean infants

shareadmin — Fri, 31 May 2019 14:34:25 +0000

This research, conducted by Church et al. (2018), explores how micronutrient deficiencies might contribute to reduced oral vaccine immunogenicity in Zimbabwean infants and how vitamin A supplements may influence this process. The work was published in Transactions of The Royal Society of Tropical Medicine and Hygiene. A cross-sectional study of 181 infants recruited at birth to the Zimbabwe Vitamin A for Mothers and Babies (ZVITAMBO) trial in Zimbawe (1197 – 2001) was carried out and poliovirus-specific IgA to type 1–3 polio strains was measured. Their results showed no significant effect of neonatal vitamin A supplements augmenting oral polio vaccine responses in Zimbabwean infants.

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Immune responses to oral poliovirus vaccine in HIV-exposed uninfected Zimbabwean infants

shareadmin — Fri, 31 May 2019 14:25:02 +0000

Church et al. (2017) published this paper in Human Vaccines & Immunotherapeutics. The research attempts to clarify whether HIV-exposed uninfected (HEU) infants have impaired responses to oral vaccines. A cross-sectional study of infants recruited at birth to the Zimbabwe Vitamin A for Mothers and Babies (ZVITAMBO) trial in Zimbawe (1197 – 2001) was carried out. Poliovirus-specific IgA to type 1–3 polio strains was measured in 85 HEU and 101 HIV-unexposed infants at 6 months of age, one month after their last immunisation with trivalent oral poliovirus vaccine. Almost all of the infants were breastfed. The results suggested that vertical HIV exposure does not impact oral poliovirus vaccine immunogenicity.

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Aetiology of Diarrhoea in Children Under Five in Zambia Detected Using Luminex xTAG Gastrointestinal Pathogen Panel

shareadmin — Tue, 17 Jul 2018 14:43:04 +0000

This study, conducted by Chisenga et al. (2018) and published in Pediatric Infectious Disease, aimed to document viral, bacterial and protozoan enteric pathogens responsible for causing moderate-to-severe diarrhoea among children under five presenting at public health facilities in Zambia following the introduction of rotavirus vaccination. This was a cross-sectional study in which clinical data and stool samples were collected between July 2012 and October 2013 from children under five years presenting to outpatient clinics in Lusaka province with moderate-tosevere diarrhoea. The study was conducted during the early months post rotavirus vaccine introduction in Zambia. We used Luminex x-TAG® gastrointestinal pathogen panel to simultaneously detect enteric viruses, bacteria and protozoa from the stool samples. We applied the population attributable fraction to estimate pathogen-specific burden of moderate-to-severe diarrhoea. We analysed 1,135 unique stool samples with clinical data, of which 56% had received one or full dose rotavirus vaccination. The median age was 14 months (IQR=8, 22). The prevalence of moderate-to-severe diarrhoea was estimated as 18.9% (95%CI=16.7, 21.2). The most attributable cases of moderate-to-severe diarrhoea were due to rotavirus {attributable fraction=24.5%; 95%CI=(5.4, 39.7)} followed by Shigella spp. {attributable fraction=6.7%; 95%CI=(0.1, 15.5)}. The top 5 enteric pathogens detected among children were rotavirus (67.6%), Adenovirus (41.5%), ETEC (40.7%), Salmonella (38.4%) and Giardia (37.0%). We found that about one-third of moderate-tosevere diarrhoea among children were attributable to rotavirus and Shigella spp.

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Effect of innate antiviral glycoproteins in breast milk on seroconversion to rotavirus vaccine (Rotarix) in children in Lusaka, Zambia

shareadmin — Tue, 20 Feb 2018 07:04:26 +0000

Rotavirus vaccines have been introduced into national immunization programmes to mitigate morbidity and mortality associated rotavirus diarrhoea. Lower vaccine effectiveness has however been noted in low-middle income countries, but little is known about the role of maternal components found in breast milk. This study assessed the effect of lactoferrin, lactadherin, and tenascin-c on rotavirus vaccine seroconversion.

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Immunogenicity of rotavirus vaccine (RotarixTM) in infants with environmental enteric dysfunction

shareadmin — Fri, 05 Jan 2018 11:10:54 +0000

Deployment of rotavirus vaccines has contributed to significant declines in diarrheal morbidity and mortality globally. Unfortunately, vaccine performance in low-middle income countries (LMICs) is generally lower than in developed countries. The cause for this has been associated with several host and maternal factors including poor WASH status, which are predominant in LMICs. More recently, environmental enteric dysfunction (EED) has specifically been hypothesized to contribute to poor vaccine uptake and response. The aim of this study was to examine the association between serological biomarkers of EED and seroconversion to rotavirus vaccine in Zambian infants.

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WASH and Vaccines - Progress Report

shareadmin — Tue, 20 Jun 2017 15:48:47 +0000

This progress report highlights updates to the WASH and vaccines research project up to May 2017. The summary report includes an overview of the project's aims and objectives, progress on key milestones, in addition to challenges and successes.

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Infographic - WASH and Vaccines: A Comprehensive Evaluation of Diarrhoea Among Rotavirus Immunized Child Populations in Zambia

shareadmin — Fri, 16 Jun 2017 09:15:56 +0000

This infographic provides an overview of rotavirus vaccine research being conducted by CIDRZ as part of SHARE Phase II. The project aims to find out the prevalence of markers of environmental enteric dysfunction and how they affect rotavirus vaccine immonogenicity, as well as the common causes of diarrhoea in Zambia after rotavirus vaccines were introduced.

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Contribution of Maternal Immunity to Decreased Rotavirus Vaccine Performance in Low- and Middle-Income Countries

shareadmin — Mon, 20 Feb 2017 07:12:23 +0000

The role of maternal immunity, received by infants either transplacentally or orally from breast milk, in rotavirus vaccine (RV) performance is evaluated here. Breastfeeding withholding has no effect on vaccine responses, but higher levels of transplacental rotavirus-specific IgG antibody contribute to reduced vaccine seroconversion. The gaps in knowledge on the factors associated with low RV efficacy in low- and middle-income countries remain, and further research is needed to shed more light on these issues.

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WASH and Vaccines

shareadmin — Tue, 13 Dec 2016 10:23:43 +0000

Diarrhoea is the second leading cause of death in children under five worldwide (Liu L, 2012), and rotavirus is well documented as the principal cause of severe and moderate diarrhoea. Under SHARE Phase II, the Centre for Infectious Disease Research in Zambia (CIDRZ) - uniquely situated at the forefront of diarrhoeal surveillance efforts in Zambia – is conducting research to better understand the role of pathogens on oral vaccine failure, which may help to explain why the rotavirus vaccine has low levels of effectiveness in high burden settings.

This study aims to simultaneously evaluate the viral, bacterial and protozoal aetiologies of moderate-to-severe diarrhoea in Zambian children under the age of five. Researchers will evaluate of the presence of these pathogens among those with diarrhoea who have been immunized with the rotavirus vaccine and those who have not, as well as among a control group of children without diarrhoea.

Vaccines Zambia

Dr Joseph Katema, former Minister of Community Development, Mother and Child Health, giving the first Rotavirus Vaccine to a child in Zambia.

Centre for Infectious Disease Research in Zambia Design Roma.Chilengi@cidrz.org 2016 to 2018