School of Public Health (Journal Articles)

Permanent URI for this collectionhttps://hdl.handle.net/10539/37879

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Start date: 2020Has files: Yes

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    Impact of witnessing abuse of their mother and childhood trauma on men’s perpetration of intimate partner violence in the cross-sectional UN multi-country study on men and violence in Asia and the Pacific
    (Elsevier, 2025-01) Jewkes, Rachel; Shai, Nwabisa; Chirwa, Esnat; Naved, Ruchira Tabassum; Abrahams, Naeema; Ramsoomar, Leane; Dekel, Bianca; Gibbs, Andrew; Nothling, Jani; Willan, Samantha
    Trauma exposure and witnessing intimate partner violence (IPV) in childhood are recognised risk factors for IPV. Using the UN Multi-country Study on Men and Violence in Asia and the Pacific dataset, we describe the pathways through which they influence adult IPV perpetration. Methods: In nine sites, from six countries, data were collected in a two-stage, randomly-selected household survey, with one man aged 18–49 years interviewed per house. 8379 interviews were completed with ever partnered men in Bangladesh, Cambodia, China, Indonesia, Papua New Guinea (Bougainville) and Sri Lanka. We present a Structural Equation Model (SEM) to understand paths through which childhood trauma and witnessing IPV impacted perpetration of physical or sexual IPV in adulthood. Results: Among the men, 25.5% had witnessed IPV, 47.0% had perpetrated physical or sexual IPV. Both wit nessing IPV and childhood trauma elevated the likelihood of such perpetration. The SEM showed four paths from witnessing IPV and childhood trauma to the latent variable for physical/sexual IPV perpetration. One was direct and three indirect. Paths were mediated by food insecurity, depression, and a latent variable measuring gender inequitable and anti-social masculinities. The masculinity variable indicators were drug use, harmful alcohol use, bullying, gang membership, fighting with other men, having sex with a sex worker and having raped a non partner. The direct and indirect effects showed both childhood trauma and witnessing maternal IPV to be important, but childhood trauma the more so. Conclusions: Both childhood trauma and witnessing IPV were important in driving IPV perpetration, with in dependent effects, however, broader childhood trauma exposure was most strongly associated. The effects were mediated by food insecurity, depression and gender inequitable and anti-social masculinities, all recognised risk factors for IPV perpetration. Thus, gender transformative IPV prevention interventions that include mental health and economic elements can mitigate the influence of these key exposures.
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    Comparable safety and non‑inferior immunogenicity of the SARS‑CoV‑2 mRNA vaccine candidate PTX‑COVID19‑B and BNT162b2 in a phase 2 randomized, observer‑blinded study
    (Nature Research, 2024) Madhi, Shabir A.; Tran, Richard; Martin‑Orozco, Natalia; Panicker, Rajesh Krishnan Gopalakrishna; Pastrak, Aleksandra; Reiter, Lawrence; Grefrath, Johann; Zidel, Bian; Ostrowski, Mario; Gommerman, Jennifer; Cooper, Curtis
    In the aftermath of the COVID-19 pandemic, the evolution of the SARS-CoV-2 into a seasonal pathogen along with the emergence of new variants, underscores the need for dynamic and adaptable responses, emphasizing the importance of sustained vaccination strategies. This observer-blind, double-dummy, randomized immunobridging phase 2 study (NCT05175742) aimed to compare the immunogenicity induced by two doses of 40 μg PTX-COVID19-B vaccine candidate administered 28 days apart, with the response induced by two doses of 30 µg Pfzer-BioNTech COVID-19 vaccine (BNT162b2), administered 21 days apart, in Nucleocapsid-protein seronegative adults 18–64 years of age. Both vaccines were administrated via intramuscular injection in the deltoid muscle. Two weeks after the second dose, the neutralizing antibody (NAb) geometric mean titer ratio and seroconversion rate met the non-inferiority criteria, successfully achieving the primary immunogenicity endpoints of the study. PTX-COVID19-B demonstrated similar safety and tolerability profle to BNT162b2 vaccine. The lowest NAb response was observed in subjects with low-to-undetectable NAb at baseline or no reported breakthrough infection. Conversely, participants who experienced breakthrough infections during the study exhibited higher NAb titers. This study also shows induction of cell-mediated immune (CMI) responses by PTX-COVID19-B. In conclusion, the vaccine candidate PTX-COVID19-B demonstrated favourable safety profle along with immunogenicity similar to the active comparator BNT162b2 vaccine.
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    T‑cell responses to ancestral SARS‑CoV‑2 and Omicron variant among unvaccinated pregnant and postpartum women living with and without HIV in South Africa
    (Nature Research, 2024-09) Madhi, Shabir A.; McMahon, William C.; Kwatra, Gaurav; Izu, Alane; Jones, Stephanie A.; Mbele, Nkululeko J.; Jafta, Nwabisa; Lala, Rushil; Shalekof, Sharon; Tiemessen, Caroline T.; Nunes, Marta C.
    SARS-CoV-2 cell-mediated immunity remains understudied during pregnancy in unvaccinated Black African women living with HIV (WLWH) from low- and middle-income countries. We investigated SARS-CoV-2-specifc T-cell responses 1 month following infection in 24 HIV-uninfected women and 15 WLWH at any stage during pregnancy or postpartum. The full-length spike (FLS) glycoprotein and nucleocapsid (N) protein of wild-type (WT) SARS-CoV-2, as well as mutated spike protein regions found in the Omicron variant (B.1.1.529) were targeted by flow cytometry. WT-specific CD4+and CD8+T cells elicited similar FLS- and N-specific responses in HIV-uninfected women and WLWH. SARS-CoV 2-specifc T-lymphocytes were predominantly TNF-α monofunctional in pregnant and postpartum women living with and without HIV, with fever cells producing either IFN-γ or IL-2. Furthermore, T-cell responses were unaffected by Omicron-specific spike mutations as similar responses between Omicron and the ancestral virus were detected for CD4+ and CD8+ T cells. Our results collectively demonstrate comparable T-cell responses between WLWH on antiretroviral therapy and HIV-uninfected pregnant and postpartum women who were naïve to Covid-19 vaccination. Additionally, we show that T cells from women infected with the ancestral virus, Beta variant (B.1.351), or Delta variant (B.1.617.2) can cross-recognize Omicron, suggesting an overall preservation of T-cell immunity.
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    Reagent‑free detection of Plasmodium falciparum malaria infections in feld‑collected mosquitoes using mid‑infrared spectroscopy and machine learning
    (Nature Research, 2024) Okumu, Fredos O.; Mwanga, Emmanuel P.; Kweyamba, Prisca A.; Siria, Doreen J.; Mshani, Issa H.; Mchola, Idrisa S.; Makala, Faraja E.; Seleman, Godian; Abbasi, Said; Mwinyi, Sophia H.; González‑Jiménez, Mario; Waynne, Klaas; Baldini, Francesco; Babayan, Simon A.
    Field-derived metrics are critical for efective control of malaria, particularly in sub-Saharan Africa where the disease kills over half a million people yearly. One key metric is entomological inoculation rate, a direct measure of transmission intensities, computed as a product of human biting rates and prevalence of Plasmodium sporozoites in mosquitoes. Unfortunately, current methods for identifying infectious mosquitoes are laborious, time consuming, and may require expensive reagents that are not always readily available. Here, we demonstrate the frst feld-application of mid-infrared spectroscopy and machine learning (MIRS-ML) to swiftly and accurately detect Plasmodium falciparum sporozoites in wild-caught Anopheles funestus, a major Afro-tropical malaria vector, without requiring any laboratory reagents. We collected 7178 female An. funestus from rural Tanzanian households using CDC-light traps, then desiccated and scanned their heads and thoraces using an FT-IR spectrometer. The porozoite infections were confrmed using enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), to establish references for training supervised algorithms. The XGBoost model was used to detect sporozoite-infectious specimen, accurately predicting ELISA and PCR outcomes with 92% and 93% accuracies respectively. These fndings suggest that MIRS-ML can rapidly detect P. falciparum in feld-collected mosquitoes, with potential for enhancing surveillance in malaria-endemic regions. The technique is both fast, scanning 60–100 mosquitoes per hour, and cost-efcient, requiring no biochemical reactions and therefore no reagents. Given its previously proven capability in monitoring key entomological indicators like mosquito age, human blood index, and identities of vector species, we conclude that MIRS-ML could constitute a low-cost multi-functional toolkit for monitoring malaria risk and evaluating interventions.