CIDRZ Research
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The CIDRZ Research Repository serves as an open-access archive for peer-reviewed publications, conference papers, and other scholarly outputs from CIDRZ researchers. Our goal is to promote the dissemination of knowledge and support evidence-based public health initiatives.
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Item Human cytomegalovirus seropositivity and its influence on oral rotavirus vaccine immunogenicity: a specific concern for HIV-exposed-uninfected infants.(2024-Jun-20) Laban N; Bosomprah S; Chilengi R; Simuyandi M; Chisenga C; Ng'ombe H; Musukuma-Chifulo K; Goodier M; Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.; Flow Cytometry and Immunology Facility, Medical Research Council Unit, The Gambia at London School of Hygiene and Tropical Medicine, Fajara, Banjul, The Gambia.; Department of Biostatistics, School of Public Health, University of Ghana, Accra, Ghana.; Enteric Disease and Vaccine Research Unit, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)Oral rotavirus vaccines demonstrate diminished immunogenicity in low-income settings where human cytomegalovirus infection is acquired early in childhood and modulates immunity. We hypothesized that human cytomegalovirus infection around the time of vaccination may influence immunogenicity. We measured plasma human cytomegalovirus-specific immunoglobulin M antibodies in rotavirus vaccinated infants from 6 weeks to 12 months old and compared rotavirus immunoglobulin A antibody titers between human cytomegalovirus seropositive and seronegative infants. There was no evidence of an association between human cytomegalovirus serostatus at 9 months and rotavirus-specific antibody titers at 12 months (geometric mean ratio 1.01, 95% CI: 0.70, 1.45; P = 0.976) or fold-increase in RV-IgA titer between 9 and 12 months (risk ratio 0.999, 95%CI: 0.66, 1.52; P = 0.995) overall. However, HIV-exposed-uninfected infants who were seropositive for human cytomegalovirus at 9 months old had a 63% reduction in rotavirus antibody geometric mean titers at 12 months compared to HIV-exposed-uninfected infants who were seronegative for human cytomegalovirus (geometric mean ratio 0.37, 95% CI: 0.17, 0.77; P = 0.008). While the broader implications of human cytomegalovirus infections on oral rotavirus vaccine response might be limited in the general infant population, the potential impact in the HIV-exposed-uninfected infants cannot be overlooked. This study highlights the complexity of immunological responses and the need for targeted interventions to ensure oral rotavirus vaccine efficacy, especially in vulnerable subpopulations.Item Seroconversion and Kinetics of Vibriocidal Antibodies during the First 90 Days of Re-Vaccination with Oral Cholera Vaccine in an Endemic Population.(2024-Apr-08) Chisenga CC; Phiri B; Ng'ombe H; Muchimba M; Musukuma-Chifulo K; Silwamba S; Laban NM; Luchen C; Liswaniso F; Chibesa K; Mubanga C; Mwape K; Simuyandi M; Cunningham AF; Sack D; Bosomprah S; Department of Biostatistics, School of Public Health, University of Ghana, Accra P.O. Box LG13, Ghana.; Enteric Disease and Vaccine Research Unit, Centre for Infectious Disease Research in Zambia, Lusaka P.O. Box 34681, Zambia.; Center for Immunization Research, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.; Institute of Immunology and Immunotherapy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)Despite the successful introduction of oral cholera vaccines, Zambia continues to experience multiple, sporadic, and protracted cholera outbreaks in various parts of the country. While vaccines have been useful in staying the cholera outbreaks, the ideal window for re-vaccinating individuals resident in cholera hotspot areas remains unclear. Using a prospective cohort study design, 225 individuals were enrolled and re-vaccinated with two doses of Shanchol™, regardless of previous vaccination, and followed-up for 90 days. Bloods were collected at baseline before re-vaccination, at day 14 prior to second dosing, and subsequently on days 28, 60, and 90. Vibriocidal assay was performed on samples collected at all five time points. Our results showed that anti-LPS and vibriocidal antibody titers increased at day 14 after re-vaccination and decreased gradually at 28, 60, and 90 days across all the groups. Seroconversion rates were generally comparable in all treatment arms. We therefore conclude that vibriocidal antibody titers generated in response to re-vaccination still wane quickly, irrespective of previous vaccination status. However, despite the observed decline, the levels of vibriocidal antibodies remained elevated over baseline values across all groups, an important aspect for Zambia where there is no empirical evidence as to the ideal time for re-vaccination.Item The Incidence and Risk Factors for Enterotoxigenic(2024-Mar-29) Sukwa N; Bosomprah S; Somwe P; Muyoyeta M; Mwape K; Chibesa K; Luchen CC; Silwamba S; Mulenga B; Munyinda M; Muzazu S; Chirwa M; Chibuye M; Simuyandi M; Chilengi R; Svennerholm AM; Centre for Infectious Disease Research in Zambia (CIDRZ), Lusaka P.O. Box 34681, Zambia.; Department of Microbiology and Immunology, University of Gothenburg, 40530 Gothenburg, Sweden.; Department of Biostatistics, School of Public Health, University of Ghana, Accra P.O. Box LG13, Ghana.This study aimed to estimate the incidence and risk factors for EnterotoxigenicItem Comparative analysis of cholera serum vibriocidal antibodies from Convalescent and vaccinated adults in Zambia.(2024-Aug-13) Ng'ombe H; Bosomprah S; Phiri B; Muchimba M; Liswaniso F; Chibuye M; Luchen CC; Chibesa K; Musukuma-Chifulo K; Mwape K; Tigere S; Silwamba S; Sinkala A; Simuyandi M; Mbewe N; Kapaya F; Cunningham AF; Chilengi R; Sack D; Chisenga CC; Centre for Infectious Disease Research in Zambia, Corner of Lukasu and Danny Pule Roads, Mass Media, Lusaka, Zambia; Department of Biostatistics, School of Public Health, University of Ghana, Accra, Ghana. Electronic address: Samuel.Bosomprah@cidrz.org.; Zambia National Public Health Institute, Stand 1186, Corner of Chaholi & Addis Ababa Roads Rhodes Park, Lusaka, Zambia.; Centre for Infectious Disease Research in Zambia, Corner of Lukasu and Danny Pule Roads, Mass Media, Lusaka, Zambia.; Ministry of Health, Levy Mwanawasa University Teaching Hospital, Chainama, Off Great East, P.0 Box 310084, Lusaka, Zambia.; Institute of Immunology and Immunotherapy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.; John Hopkins University, 615 N Wolfe St, Baltimore, United States of America.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)Cholera is responsible for 1.3 to 4.0 million cholera cases globally and poses a significant threat, with Zambia reporting 17,169 cases as of 4th February 2024. Recognizing the crucial link between natural cholera infections and vaccine protection, this study aimed to assess immune responses post cholera infection and vaccination. This was a comparative study consisting of 50 participants enrolled during a cholera outbreak in Zambia's Eastern Province and an additional 56 participants who received oral cholera vaccinations in Zambia's Central Province. Vibriocidal antibodies were plotted as geometric mean titres in the naturally infected and vaccinated individuals. A significant difference (p < 0.047) emerged when comparing naturally infected to fully vaccinated individuals (2 doses) on day 28 against V. cholerae Ogawa. Those who received two doses of the oral cholera vaccine had higher antibody titres than those who were naturally infected. Notably, the lowest titres occurred between 0-9 days post onset, contrasting with peak responses at 10-19 days. This study addresses a critical knowledge gap in understanding cholera immunity dynamics, emphasizing the potential superiority of vaccination-induced immune responses. We recommend post infection vaccination after 40 days for sustained immunity and prolonged protection, especially in cholera hotspots.Item Cervical cancer prevention and care in HIV clinics across sub-Saharan Africa: results of a facility-based survey.(2024-Jul) Asangbeh-Kerman SL; Davidović M; Taghavi K; Dhokotera T; Manasyan A; Sharma A; Jaquet A; Musick B; Twizere C; Chimbetete C; Murenzi G; Tweya H; Muhairwe J; Wools-Kaloustian K; Technau KG; Anastos K; Yotebieng M; Jousse M; Ezechi O; Orang'o O; Bosomprah S; Pierre Boni S; Basu P; Bohlius J; Department of Biostatistics, School of Public Health, University of Ghana, Accra, Ghana.; SolidarMed, Partnerships for Health, Maseru, Lesotho.; Programme National de Lutte contre le Cancer (PNLCa), Abidjan, Côte d'Ivoire.; Department of Medicine and Epidemiology, Albert Einstein College of Medicine, Bronx, New York, USA.; Moi University, Eldoret, Kenya.; Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.; Programme PAC-CI, Site ANRS Treichville, Abidjan, Côte d'Ivoire.; Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland.; Newlands Clinic, Harare, Zimbabwe.; Department of Clinical Sciences, Nigerian Institute of Medical Research, Lagos, Nigeria.; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA.; Department of Paediatrics and Child Health, Rahima Moosa Mother and Child Hospital, Johannesburg-Braamfontein, South Africa.; University of Basel, Basel, Switzerland.; Empilweni Services and Research Unit, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.; Graduate School for Health Sciences, University of Bern, Bern, Switzerland.; Early Detection, Prevention and Infections Branch, International Agency for Research on Cancer, Lyon, France.; SolidarMed, Partnership for Health, Chiure, Mozambique.; Institute of Global Health, University of Geneva, Geneva, Switzerland.; Centre National de Reference en Matière de VIH/SIDA, Bujumbura, Burundi.; Division of Neonatology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama, USA.; Einstein-Rwanda Research and Capacity Building Programme, Research for Development and Rwanda Military Hospital, Kigali, Rwanda.; Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.; University of Bordeaux, National Institute for Health and Medical Research (INSERM) UMR 1219, Research Institute for Sustainable Development (IRD) EMR 271, Bordeaux Population Health Centre, Bordeaux, France.; International Training and Education Centre for Health (I-TECH), Lilongwe, Malawi.; Swiss Tropical and Public Health Institute, Allschwil, Switzerland.; Department of Biostatistics and Health Data Science, School of Medicine, Indiana University, Indianapolis, Indiana, USA.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)INTRODUCTION: To eliminate cervical cancer (CC), access to and quality of prevention and care services must be monitored, particularly for women living with HIV (WLHIV). We assessed implementation practices in HIV clinics across sub-Saharan Africa (SSA) to identify gaps in the care cascade and used aggregated patient data to populate cascades for WLHIV attending HIV clinics. METHODS: Our facility-based survey was administered between November 2020 and July 2021 in 30 HIV clinics across SSA that participate in the International epidemiology Databases to Evaluate AIDS (IeDEA) consortium. We performed a qualitative site-level assessment of CC prevention and care services and analysed data from routine care of WLHIV in SSA. RESULTS: Human papillomavirus (HPV) vaccination was offered in 33% of sites. Referral for CC diagnosis (42%) and treatment (70%) was common, but not free at about 50% of sites. Most sites had electronic health information systems (90%), but data to inform indicators to monitor global targets for CC elimination in WLHIV were not routinely collected in these sites. Data were collected routinely in only 36% of sites that offered HPV vaccination, 33% of sites that offered cervical screening and 20% of sites that offered pre-cancer and CC treatment. CONCLUSIONS: Though CC prevention and care services have long been available in some HIV clinics across SSA, patient and programme monitoring need to be improved. Countries should consider leveraging their existing health information systems and use monitoring tools provided by the World Health Organization to improve CC prevention programmes and access, and to track their progress towards the goal of eliminating CC.Item Health Promotion Through Existing Community Structures: A Case of Churches' Roles in Promoting Rotavirus Vaccination in Rural Zambia.(2016-Apr) Wesevich A; Chipungu J; Mwale M; Bosomprah S; Chilengi R; Centre for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia jenala.chipungu@cidrz.org.; Centre for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia.; Centre for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia Washington University in St. Louis, St. Louis, MO, USA.INTRODUCTION: Rural populations, particularly in Africa, suffer worse health outcomes from poor health services access. Community health workers (CHWs) effectively improve health outcomes, but the best means for CHWs reaching rural populations is unknown. Since Zambia is predominantly Christian, this study explored the use of CHWs through churches as an existing community structure for promoting preventive health behaviors, specifically rotavirus vaccine uptake. METHODS: A noncontrolled cross-sectional study of 32 churches receiving a packaged intervention of diarrhea prevention and treatment messaging was conducted with repeated time points of data collection over 13 months (2013-2014) in the Kafue District of Zambia. Two churches were selected for each of the 17 catchment areas, and CHWs were identified and trained in the intervention of promoting 4 key messages related to diarrhea prevention and treatment: hand washing with soap, exclusive breast-feeding, rotavirus vaccination, and treating diarrhea with oral rehydration solution and zinc. The intervention was conducted within existing church's women's groups, and data was collected on attendance and the distribution of Rota Cards for tracking rotavirus immunizations. RESULTS: Nineteen (59%) churches completed the study, and CHWs delivered health messages at a total of 890 women's group meetings. The overall reach of the intervention was to 37.0% of church-attending women, and the efficacy was 67.7% (317 of 468 Rota Cards collected at health centers). DISCUSSION: Implementing community health programs is often expensive and unsustainable, but the reach and efficacy levels achieved through existing structures like churches are encouraging in resource-constrained countries. Churches can be effective channels for delivering health prevention strategies to often difficult-to-reach rural populations. Further research is needed to investigate the impact of the intervention on health outcomes.Item Association of Maternal Immunity with Rotavirus Vaccine Immunogenicity in Zambian Infants.(2016) Chilengi R; Simuyandi M; Beach L; Mwila K; Becker-Dreps S; Emperador DM; Velasquez DE; Bosomprah S; Jiang B; University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Centres for Disease Control and Prevention, Atlanta, Georgia, United States of America.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)INTRODUCTION: Live attenuated oral vaccines against rotavirus (RV) have been shown to be less efficacious in children from developing countries. Reasons for this disparity are not fully understood. We assessed the role of maternal factors including breast milk RV-specific IgA, transplacentally acquired infant serum RV-specific IgG and maternal HIV status in seroconversion among Zambian infants routinely immunized with Rotarix™ (RV1). METHODS: 420 mother-child pairs were recruited at infant age 6-12 weeks in Lusaka. Clinical information and samples were collected at baseline and at one month following the second dose of RV1. Determination of breast milk RV-specific IgA and serum RV-specific IgA and IgG was done using standardized ELISA. Seroconversion was defined as a ≥ 4 fold rise in serum IgA titre from baseline to one-month post RV1 dose 2, while seropositivity of IgA was defined as serum titre ≥ 40 and antibody variables were modelled on log-base 2. Logistic regression was used to identify predictors of the odds of seroconversion. RESULTS: Baseline infant seropositivity was 25.5% (91/357). The seroconversion frequency was 60.2% (130/216). Infants who were IgA seropositive at baseline were less likely to seroconvert compared to their seronegative counterparts (P = 0.04). There was no evidence of an association between maternal HIV status and seroconversion (P = 0.25). Higher titres of breast milk rotavirus-specific IgA were associated with a lower frequency of seroconverson (Nonparametric test for trend Z = -2.84; P<0.01): a two-fold increase in breast milk RV-specific IgA titres was associated with a 22% lower odds of seroconversion (OR = 0.80; 95% CI = 0.68-0.94; P = 0.01). There was seasonal variation in baseline breast milk rotavirus-specific IgA titres, with significantly higher GMTs during the cold dry months (P = 0.01). CONCLUSION: Low immunogenicity of RV1 vaccine could be explained in part by exposure to high antibody titres in breast milk and early exposure to wild-type rotavirus infections. Potential interference of anti-RV specific IgA in breast milk and pre-vaccination serum RV specific-IgA and IgG titres with RV1 seroconversion and effectiveness requires further research.Item Diagnostic accuracy of saliva-based testing as a Vibrio cholerae surveillance tool among naturally infected patients.(2025-Jan-21) Chisenga CC; Phiri B; Ng'ombe H; Muchimba M; Liswaniso F; Bernshtein B; Cunningham AF; Sack D; Bosomprah S; Department of Biostatistics, School of Public Health, University of Ghana, Accra, Ghana.; Enteric Disease and Vaccine Research Unit, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Institute of Immunology and Immunotherapy, University of Birmingham, Edgbaston, Birmingham, UK.; Center for Immunization Research, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.; Alter Lab, Ragon Institute of MGH, MIT and Harvard, Boston, USA.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)Saliva, as a diagnostic medium, offers a promising alternative to blood by virtue of its non-invasive collection, which enhances patient compliance, especially in paediatric and geriatric populations. In this study, we assessed the utility of saliva as a non-invasive medium for measuring Vibrio cholerae-specific serum antibodies in naturally infected individuals. We tested paired serum and saliva samples obtained from a total of 63 patients with cholera enrolled in a cohort study. Vibriocidal antibodies assay (IgM/IgG) as markers for accurate determination was used to determine cholera-specific antibody levels. Using receiver operating characteristics (ROC) curve, we found that the best cut-off that maximizes (sensitivity + specificity) is 10 titres. At this saliva titre, the sensitivity is 76.9% (95%CI: 60.9%, 87.7%) and specificity is 80.0% (95%CI: 56.6%, 92.5%). Using Spearman's correlation coefficient, we also found evidence of a positive correlation between V. cholerae saliva and serum antibodies (rho = 0.66, P < 0.001). In conclusion, saliva-based diagnostic cholera tests have high diagnostic accuracy and would be advantageous, cheaper, and quicker for early diagnosis of severe cholera outcomes.Item Marketing of breast-milk substitutes in Zambia: evaluation of compliance to the international regulatory code.(2018-Mar-01) Funduluka P; Bosomprah S; Chilengi R; Mugode RH; Bwembya PA; Mudenda B; Immunomedics Inc., 300, American Rd., Morris Plains, NJ, USA.; Centre for Infectious Diseases Research in Zambia, Box 3481, Lusaka, Zambia.; School of Public Health, University of Zambia, Box 50110, Lusaka, Zambia.; National Food and Nutrition Commission, Lumumba Road, Box 32669, Lusaka, Zambia.; Chainama College of Health Sciences, Box 33991, Lusaka, Zambia.; Department of Biostatistics, School of Public Health, University of Ghana, P.O. Box LG 25 Legon, Accra.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)BACKGROUND: We sought to assess the level of non-compliance with the International Code of Marketing breast-milk substitutes (BMS) and/or Statutory Instrument (SI) Number 48 of 2006 of the Laws of Zambia in two suburbs, Kalingalinga and Chelstone, in Zambia. METHODS: This was a cross sectional survey. Shop owners (80), health workers (8) and mothers (214) were interviewed. BMS labels and advertisements (62) were observed. The primary outcome was mean non-compliance defined as the number of article violations divided by the total 'obtainable' violations. The score ranges from 0 to 1 with 0 representing no violations in all the articles and one representing violations in all the articles. RESULTS: A total of 62 BMS were assessed. The mean non-compliance score by manufacturers in terms of violations in labelling of BMS was 0.33 (SD = 0.28; 95% CI: 0.26, 0.40). These violations were mainly due to labels containing pictures or graphics representing an infant. 80 shops were also assessed with mean non-compliance score in respect of violations in tie-in-sales, special display, and contact with mothers at the shop estimated as 0.14 (SD = 0.14; 95% CI: 0.11, 0.18). CONCLUSIONS: Non-compliance with the Code and/or the local SI is high after 10 years of domesticating the Code.Item COVID-19 vaccine uptake and associated risk factors among first antenatal care attendees in Zambia, 2021-2022: A repeated cross-sectional study.(2024) Tembo T; Somwe P; Bosomprah S; Heilmann E; Kalenga K; Moyo N; Kabamba B; Seffren V; Fwoloshi S; Rutagwera MR; Musunse M; Mwiinga L; Gutman JR; Hines JZ; Sikazwe I; Analysis Unit, Center for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia.; Department of Biostatistics, School of Public Health, University of Ghana, Accra, Accra.; Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.; Centers for Disease Control and Prevention, Lusaka, Zambia.; PATH, Lusaka, Zambia.; Reproductive, Maternal, Newborn and Child Health (RMNCH), Center for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia.; University Teaching Hospital, Ministry of Health, Lusaka, Zambia.; Center for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia.; Strategic Information Unit, Center for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia.Pregnant women are considered a high-risk group for COVID-19, and a priority for vaccination. Routine antenatal care (ANC) provides an opportunity to track trends and factors associated with vaccine uptake. We sought to evaluate COVID-19 vaccine uptake among pregnant women attending ANC and assess the factors associated with vaccine in Zambia. We conducted a repeated cross-sectional study in 39 public health facilities in four districts in Zambia from September 2021 to September 2022. Pregnant women who were aged 15-49 years were enrolled during their first ANC visit. Every month, ~20 women per facility were interviewed during individual HIV counseling and testing. We estimated vaccine uptake as the proportion of eligible participants who self-reported having received the COVID-19 vaccine. A total of 9,203 pregnant women were screened, of which 9,111 (99%) were eligible and had vaccination status. Of the 9,111 included in the analysis, 1,818 (20%) had received the COVID-19 vaccine during the study period, with a trend of increasing coverage with time (0.5% in September 2020, 27% in September 2022). Conversely, 3,789 (42%) reported not being offered a COVID-19 vaccine. We found that women aged 40-49 years, had no education or attained some primary school education, were not employed, and had prior COVID-19 infection were significantly associated with vaccine uptake. COVID-19 vaccine uptake among pregnant women was lower than estimates from the general population (27% across the four districts in September 2022), pointing to missed opportunities to protect this high-risk group. ANC visits were a viable point for conducting COVID-19 surveillance. Incorporating the vaccine as part of the routine ANC package might increase coverage in this group.