NRU :: Browsing by Author "Zirimenya, Ludoviko"

Browsing by Author "Zirimenya, Ludoviko"

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A systematic review and meta-analysis to assess the association between urogenital schistosomiasis and HIV/AIDS infection
(PLoS Neglected Tropical Diseases, 2020-06-15) Zirimenya, Ludoviko; Mahmud-Ajeigbe, Fatima; McQuillan, Ruth; Li, You
Urogenital schistosomiasis and HIV/AIDS infections are widespread in sub-Saharan Africa (SSA) leading to substantial morbidity and mortality. The co-occurrence of both diseases has led to the possible hypothesis that urogenital schistosomiasis leads to increased risk of acquiring HIV infection. However, the available evidence concerning this association is inconsistent. The aim of this study was to systematically review and quantitatively synthesize studies that investigated the association between urogenital schistosomiasis and HIV/AIDS infection.
Assessing community vulnerability to reduced vaccine impact in Uganda and Kenya: A spatial data analysis
(NIHR Open Research, 2025-03-17) Nalwanga, Robinah; Natukunda, Agnes; Zirimenya, Ludoviko; Kaleebu, Pontiano; Webb, Emily L.
Despite global efforts to improve on vaccine impact, many African countries have failed to achieve equitable vaccine benefits. Reduced vaccine impact may arise from interplay between structural, social, and biological factors, that hinder communities from achieving full benefits from vaccination programs. However, the combined influence of these factors to reduced vaccine impact and the spatial distribution of vulnerable communities remains poorly understood. In this work, we developed a Community Vaccine Impact Vulnerability Index (CVIVI) that integrates data on multiple risk factors associated with impaired vaccine impact. The index identifies communities are at risk of reduced vaccine impact, and key factors contributing to their vulnerability.
Effect of intensive treatment for schistosomiasis on immune responses to vaccines among rural Ugandan island adolescents: randomised controlled trial protocol A for the ‘POPulation differences in VACcine responses’ (POPVAC) programme
(BMJ open, 2021-02-16) Nkurunungi, Gyaviira; Zirimenya, Ludoviko; Nassuuna, Jacent; Niwagaba, Emmanuel; Amongi, Susan
Several licensed and investigational vaccines have lower efficacy, and induce impaired immune responses, in low-income versus high-income countries and in rural, versus urban, settings. Understanding these population differences is essential to optimising vaccine effectiveness in the tropics. We suggest that repeated exposure to and immunomodulation by chronic helminth infections partly explains population differences in vaccine response.
Helminth driven gut inflammation and microbial translocation associate with altered vaccine responses in rural Uganda
(npj Vaccines, 2025-03-26) Nassuuna, Jacent; Walusimbi, Bridgious; Natukunda, Agnes; Zirimenya, Ludoviko
Vaccine responses are sometimes impaired in rural, low-income settings. Helminth-associated gut barrier dysfunction and microbial translocation (MT) may be implicated. We used samples from a trial of praziquantel treatment-effects on vaccine responses in Schistosoma mansoni (Sm)-endemic Ugandan islands, measuring intestinal fatty acid-binding protein 2 (I-FABP2), lipopolysaccharide-binding protein, anti-endotoxin core antibodies (EndoCab), soluble CD14 (sCD14) in plasma, and faecal lipocalin-2, occult blood (FOB), and calprotectin (fCAL), and evaluating their associations with baseline helminth infection, praziquantel treatment, and responses to BCG, yellow fever, typhoid, HPV, and tetanus-diphtheria vaccines. Sm associated positively with fCAL and FOB, hookworm with I-FABP2, and any helminth with EndoCab IgM, fCAL and FOB. Sm associated inversely with sCD14. Praziquantel treatment reduced all marker concentrations, significantly fCAL and FOB, implying that Sm-associated gut inflammation and MT is reversible. Associations of assessed markers with vaccine-specific responses were predominantly inverse. Interventions to improve gut barrier function may enhance vaccine responsiveness.
NIHR Global Health Research Group on Vaccines for vulnerable people in Africa (VAnguard): Concept and Launch event report
(NIHR Open Research, 2023-06-27) Zirimenya, Ludoviko; Zalwango, Flavia; Karanja , Henry K.; Natukunda, Agnes; Kiwanuka, Achilles; Chibita, Monica
Vaccination is an important public health intervention, but not everyone benefits equally. Biological, social and structural factors render some communities vulnerable and unable to secure optimal health benefits from vaccination programmes. This drives health inequity and undermines wider vaccine impact by allowing the persistence of non-immune communities as foci for recurrent disease outbreaks. The NIHR Global Health Research Group on Vaccines for vulnerable people in Africa (VAnguard) aims to understand how biological, social, and structural factors interact to impair vaccine impact in vulnerable African communities.
Population differences in vaccine responses (POPVAC): scientific rationale and cross-cutting analyses for three linked, randomised controlled trials assessing the role, reversibility and mediators of immunomodulation by chronic infections in the tropics
(BMJ open, 2020-06-24) Nkurunungi, Gyaviira; Zirimenya, Ludoviko; Natukunda, Agnes; Ninsiima, Caroline; Akello, Mirriam
Vaccine-specific immune responses vary between populations and are often impaired in low income, rural settings. Drivers of these differences are not fully elucidated, hampering identification of strategies for optimising vaccine effectiveness. We hypothesise that urban–rural (and regional and international) differences in vaccine responses are mediated to an important extent by differential exposure to chronic infections, particularly parasitic infections. Three related trials sharing core elements of study design and procedures (allowing comparison of outcomes across the trials) will test the effects of (1) individually randomised intervention against schistosomiasis (trial A) and malaria (trial B), and (2) Bacillus Calmette-Guérin (BCG) revaccination (trial C), on a common set of vaccine responses. We will enrol adolescents from Ugandan schools in rural high-schistosomiasis (trial A) and rural high-malaria (trial B) settings and from an established urban birth cohort (trial C). All participants will receive BCG on day ‘0’; yellow fever, oral typhoid and human papilloma virus (HPV) vaccines at week 4; and HPV and tetanus/diphtheria booster vaccine at week 28. Primary outcomes are BCG-specific IFN-γ responses (8 weeks after BCG) and for other vaccines, antibody responses to key vaccine antigens at 4 weeks after immunisation. Secondary analyses will determine effects of interventions on correlates of protective immunity, vaccine response waning, priming versus boosting immunisations, and parasite infection status and intensity. Overarching analyses will compare outcomes between the three trial settings. Sample archives will offer opportunities for exploratory evaluation of the role of immunological and ‘trans-kingdom’ mediators in parasite modulation of vaccine-specific responses.
Symptom Prevalence and Burden in Cancer Patients with and without HIV/AIDS Reffered for Palliative Care
(Journal of Health Science, 2015-02-24) Zirimenya, Ludoviko; Musoke, Charles; Hutt, Evelyn
: The prevalence of cancer and that of HIV/AIDS is increasing in Uganda and throughout sub Saharan Africa. Unfortunately, little is known about the prevalence and burden of symptoms in patients with AIDS-Cancer and Cancer alone at first referral to a palliative care service. This study sets out to compare the prevalence and symptom burden between patients with AIDS-Cancer and those with Cancer only referred to a palliative care setting. Retrospective point prevalence survey of 150 randomly selected charts of patients referred to Hospice Africa Uganda (HAU) as per 2013. Of the 471 eligible patients’ charts, 168 were randomly selected and only 150 were included in the study. A chart review instrument was used to extract information from the charts. Data were entered into Epidata version 3.1, cleaned and analysed using Epidata Analysis and Excel. Of the 150 patients’ records: 78 (52%) had Cancer only diagnosis and 72 (48%) AIDS-Cancer diagnosis. Pain was most prevalent at 91.7% in the AIDS-Cancer group and 100% in the cancer only group. Three quarters reported pain as moderate to severe in both groups of patients. The five most prevalent symptoms in the AIDS-Cancer group were pain (91.7%), social distresses (38.9%), body swelling (27.8%), Anorexia (22.2%) and skin eruption (16.7%) while in the Cancer alone group were pain (100%), body swelling (25.6%), Anorexia (23.1%), social distresses (20.9%) and fatigue (17.9%). The average number of symptoms was 4.8 (2.3) in the Cancer group and 4.7 (2.3) in the AIDS-Cancer group Pain is highly prevalent in both Cancer only and AIDS-Cancer patients. The four most prevalent symptoms namely pain, social distresses, body swelling and anorexia are similar in both groups of patients. Social distresses occur highly in AIDS-Cancer patients.
The effect of BCG revaccination on the response to unrelated vaccines in urban Ugandan adolescents (POPVAC C): an open-label, randomised controlled trial
(The Lancet Global Health, 2024-11-24) Nassuuna, Jacent; Zirimenya, Ludoviko; Nkurunungi, Gyaviira; Ninsiima, Caroline; Amongi, Susan
Immune responses induced by several important vaccines differ between populations, with reduced responses in low-income and rural settings compared with high-income and urban settings. BCG immunisation boosts immune responses to some unrelated vaccines in high-income populations. We aimed to test the hypothesis that BCG revaccination can enhance responses to unrelated vaccines in Ugandan schoolchildren.
The effect of helminth infection on vaccine responses in humans and animal models: A systematic review and meta-analysis
(Parasite Immunology, 2022-06-17) Natukunda, Agnes; Zirimenya, Ludoviko; Nassuuna, Jacent; Nkurunungi, Gyaviira; Elliott, Alison M.; Webb, Emily L.
Vaccination has potential to eliminate infectious diseases. However, parasitic infections such as helminths may hinder vaccines from providing optimal protection. We reviewed existing literature on the effects of helminth infections and their treatment on vaccine responses in humans and animals. We searched literature until 31 January 2022 in Medline, EMBASE, Global health, Scopus, and Web of science; search terms included WHO licensed vaccines and human helminth types. Standardized mean differences (SMD) in vaccine responses between helminth infected and uninfected or anthelminthic treated and untreated individuals were obtained from each study with suitable data for meta-analysis, and combined using a random effects model. Analysis was stratified by whether helminth exposure was direct or prenatal and by vaccine type. This study is registered with PROSPERO (CRD42019123074). Of the 4402 articles identified, 37 were included in the review of human studies and 24 for animal experiments. For human studies, regardless of vaccine type, overall SMD for helminth uninfected/treated, compared to infected/untreated, was 0.56 (95% CI 0.04–1.07 and I2 = 93.5%) for direct helminth exposure and 0.01 (95% CI −0.04 to 0.07 and I2 = 85.9%) for prenatal helminth exposure. Effects of anthelminthic treatment were inconsistent, with no overall benefit shown. Results differed by vaccine type, with responses to live vaccines most affected by helminth exposure. For animal studies, the most affected vaccine was BCG. This result indicates that helminth-associated impairment of vaccine responses is more severe for direct, than for prenatal, helminth exposure. Further research is needed to ascertain whether deworming of individuals before vaccination may help improve responses.
The Effect of Malaria on Responses to Unrelated Vaccines in Animals and Humans: A Systematic Review and Meta-Analysis
(Parasite immunology, 2024-10-24) Zirimenya, Ludoviko; Natukunda, Agnes; Nassuuna, Jacent; Nkurunungi, Gyaviira; Kabagenyi, Joyce; Webb, Emily L.
Vaccine efficacy varies globally, often showing reduced immune responses in low- and middle-income countries, possibly due to the immunomodulatory effects of parasitic infections like malaria. This systematic review evaluates the impact of malaria on immune responses to unrelated vaccines in humans and animals. We systematically searched five databases—MEDLINE, Web of Science, Global Health, Scopus and Embase—up to 5th December 2023. Eligible studies compared immune responses to WHO-approved vaccines between malaria-infected and uninfected groups, or between antimalarial-treated and untreated groups. Meta-analysis was performed using random-effects models with standardised mean differences (SMDs) as summary statistics. The study is registered with PROSPERO (CRD42022298053). Twenty-four articles (17 human, 7 animal) met the inclusion criteria, with 13 human articles contributing data for the meta-analysis. Significant heterogeneity was observed. Vaccine responses were higher in malaria uninfected individuals (SMD 0.34, 95% CI 0.07 to 0.60, I2 = 87.15%) with weaker differences between antimalarial-treated and untreated groups (SMD 0.07, 95% CI −0.01 to 0.16, I2 = 85.01%). The overall SMD for malaria uninfected/treated vs. infected/untreated was 0.15, 95% CI 0.05–0.26, I2 = 90.91. Narrative analysis suggested malaria's adverse impact on vaccine responses in animals. Malaria infection may impair vaccines responses; with preventive treatment of malaria partially reversing these effects, highlighting the need for targeted public health interventions.

Browsing by Author "Zirimenya, Ludoviko"

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