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Lourenço J, Obolski U, Swarthout TD, Gori A, Bar-Zeev N, Everett D, Kamng'ona AW, Mwalukomo TS, Mataya AA, Mwansambo C, Banda M, Gupta S, French N, Heyderman RS. Determinants of high residual post-PCV13 pneumococcal vaccine-type carriage in Blantyre, Malawi: a modelling study. BMC Med 2019; 17:219. [PMID: 31801542 PMCID: PMC6894346 DOI: 10.1186/s12916-019-1450-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/24/2019] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND In November 2011, Malawi introduced the 13-valent pneumococcal conjugate vaccine (PCV13) into the routine infant schedule. Four to 7 years after introduction (2015-2018), rolling prospective nasopharyngeal carriage surveys were performed in the city of Blantyre. Carriage of Streptococcus pneumoniae vaccine serotypes (VT) remained higher than reported in high-income countries, and impact was asymmetric across age groups. METHODS A dynamic transmission model was fit to survey data using a Bayesian Markov-chain Monte Carlo approach, to obtain insights into the determinants of post-PCV13 age-specific VT carriage. RESULTS Accumulation of naturally acquired immunity with age and age-specific transmission potential were both key to reproducing the observed data. VT carriage reduction peaked sequentially over time, earlier in younger and later in older age groups. Estimated vaccine efficacy (protection against carriage) was 66.87% (95% CI 50.49-82.26%), similar to previous estimates. Ten-year projected vaccine impact (VT carriage reduction) among 0-9 years old was lower than observed in other settings, at 76.23% (CI 95% 68.02-81.96%), with sensitivity analyses demonstrating this to be mainly driven by a high local force of infection. CONCLUSIONS There are both vaccine-related and host-related determinants of post-PCV13 pneumococcal VT transmission in Blantyre with vaccine impact determined by an age-specific, local force of infection. These findings are likely to be generalisable to other Sub-Saharan African countries in which PCV impact on carriage (and therefore herd protection) has been lower than desired, and have implications for the interpretation of post-PCV carriage studies and future vaccination programs.
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Affiliation(s)
- J Lourenço
- Department of Zoology, University of Oxford, Oxford, UK.
| | - U Obolski
- School of Public Health, Tel Aviv University, Tel Aviv, Israel.,Porter School of the Environment and Earth Sciences, Tel Aviv University, Tel Aviv, Israel
| | - T D Swarthout
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Clinical Sciences Department, Liverpool School of Tropical Medicine, Liverpool, UK
| | - A Gori
- NIHR Mucosal Pathogens Research Unit, Division of Infection & Immunity, University College London, London, UK
| | - N Bar-Zeev
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
| | - D Everett
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,The Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - A W Kamng'ona
- Department of Biomedical Sciences, College of Medicine, University of Malawi, Blantyre, Malawi
| | - T S Mwalukomo
- Department of Medicine, College of Medicine, University of Malawi, Blantyre, Malawi
| | - A A Mataya
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | - M Banda
- Ministry of Education, Blantyre, Malawi
| | - S Gupta
- Department of Zoology, University of Oxford, Oxford, UK
| | - N French
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Centre for Global Vaccine Research, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - R S Heyderman
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,NIHR Mucosal Pathogens Research Unit, Division of Infection & Immunity, University College London, London, UK
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MacLennan CA, Msefula CL, Gondwe EN, Gilchrist JJ, Pensulo P, Mandala WL, Mwimaniwa G, Banda M, Kenny J, Wilson LK, Phiri A, MacLennan JM, Molyneux EM, Molyneux ME, Graham SM. Presentation of life-threatening invasive nontyphoidal Salmonella disease in Malawian children: A prospective observational study. PLoS Negl Trop Dis 2017; 11:e0006027. [PMID: 29216183 PMCID: PMC5745124 DOI: 10.1371/journal.pntd.0006027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 12/27/2017] [Accepted: 10/10/2017] [Indexed: 12/17/2022] Open
Abstract
Nontyphoidal Salmonellae commonly cause invasive disease in African children that is often fatal. The clinical diagnosis of these infections is hampered by the absence of a clear clinical syndrome. Drug resistance means that empirical antibiotic therapy is often ineffective and currently no vaccine is available. The study objective was to identify risk factors for mortality among children presenting to hospital with invasive Salmonella disease in Africa. We conducted a prospective study enrolling consecutive children with microbiologically-confirmed invasive Salmonella disease admitted to Queen Elizabeth Central Hospital, Blantyre, in 2006. Data on clinical presentation, co-morbidities and outcome were used to identify children at risk of inpatient mortality through logistic-regression modeling. Over one calendar year, 263 consecutive children presented with invasive Salmonella disease. Median age was 16 months (range 0-15 years) and 52/256 children (20%; 95%CI 15-25%) died. Nontyphoidal serovars caused 248/263 (94%) of cases. 211/259 (81%) of isolates were multi-drug resistant. 251/263 children presented with bacteremia, 6 with meningitis and 6 with both. Respiratory symptoms were present in 184/240 (77%; 95%CI 71-82%), 123/240 (51%; 95%CI 45-58%) had gastrointestinal symptoms and 101/240 (42%; 95%CI 36-49%) had an overlapping clinical syndrome. Presentation at <7 months (OR 10.0; 95%CI 2.8-35.1), dyspnea (OR 4.2; 95%CI 1.5-12.0) and HIV infection (OR 3.3; 95%CI 1.1-10.2) were independent risk factors for inpatient mortality. Invasive Salmonella disease in Malawi is characterized by high mortality and prevalence of multi-drug resistant isolates, along with non-specific presentation. Young infants, children with dyspnea and HIV-infected children bear a disproportionate burden of the Salmonella-associated mortality in Malawi. Strategies to improve prevention, diagnosis and management of invasive Salmonella disease should be targeted at these children.
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Affiliation(s)
- Calman A. MacLennan
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- * E-mail:
| | - Chisomo L. Msefula
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Department of Microbiology, College of Medicine, University of Malawi, Malawi
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Esther N. Gondwe
- School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
- Department of Biochemistry, College of Medicine, University of Malawi, Malawi
| | - James J. Gilchrist
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Department of Paediatrics, University of Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, United Kingdom
| | - Paul Pensulo
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Wilson L. Mandala
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
- Department of Basic Medical Sciences, College of Medicine, University of Malawi, Blantyre, Malawi
- Academy of Medical Sciences, Malawi University of Science and Technology, Thyolo, Malawi
| | - Grace Mwimaniwa
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Meraby Banda
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Julia Kenny
- Department of Paediatrics, College of Medicine, University of Malawi, Malawi
- Infectious Diseases and Microbiology Unit, Institute of Child Health, University College London, London, United Kingdom
| | - Lorna K. Wilson
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Amos Phiri
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Jenny M. MacLennan
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | | | - Malcolm E. Molyneux
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
- Department of Medicine, College of Medicine, University of Malawi, Malawi
| | - Stephen M. Graham
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Department of Paediatrics, College of Medicine, University of Malawi, Malawi
- Centre for International Child Health, University of Melbourne and Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, Australia
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Banda M. Return to work of post-chemotherapy caner survivors: what is the effect of exercise training on the return to work? Intern Med J 2017. [DOI: 10.1111/imj.7_13456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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King C, Zamawe C, Banda M, Bar-Zeev N, Beard J, Bird J, Costello A, Kazembe P, Osrin D, Fottrell E. The quality and diagnostic value of open narratives in verbal autopsy: a mixed-methods analysis of partnered interviews from Malawi. BMC Med Res Methodol 2016; 16:13. [PMID: 26830814 PMCID: PMC4736636 DOI: 10.1186/s12874-016-0115-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 01/23/2016] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Verbal autopsy (VA), the process of interviewing a deceased's family or caregiver about signs and symptoms leading up to death, employs tools that ask a series of closed questions and can include an open narrative where respondents give an unprompted account of events preceding death. The extent to which an individual interviewer, who generally does not interpret the data, affects the quality of this data, and therefore the assigned cause of death, is poorly documented. We aimed to examine inter-interviewer reliability of open narrative and closed question data gathered during VA interviews. METHODS During the introduction of VA data collection, as part of a larger study in Mchinji district, Malawi, we conducted partner interviews whereby two interviewers independently recorded open narrative and closed questions during the same interview. Closed questions were collected using a smartphone application (mobile-InterVA) and open narratives using pen and paper. We used mixed methods of analysis to evaluate the differences between recorded responses to open narratives and closed questions, causes of death assigned, and additional information gathered by open narrative. RESULTS Eighteen partner interviews were conducted, with complete data for 11 pairs. Comparing closed questions between interviewers, the median number of differences was 1 (IQR: 0.5-3.5) of an average 65 answered; mean inter-interviewer concordance was 92% (IQR: 92-99%). Discrepancies in open narratives were summarized in five categories: demographics, history and care-seeking, diagnoses and symptoms, treatment and cultural. Most discrepancies were seen in the reporting of diagnoses and symptoms (e.g., malaria diagnosis); only one pair demonstrated no clear differences. The average number of clinical symptoms reported was 9 in open narratives and 20 in the closed questions. Open narratives contained additional information on health seeking and social issues surrounding deaths, which closed questions did not gather. CONCLUSIONS The information gleaned during open narratives was subject to inter-interviewer variability and contained a limited number of symptom indicators, suggesting that their use for assigning cause of death is questionable. However, they contained rich information on care-seeking, healthcare provision and social factors in the lead-up to death, which may be a valuable source of information for promoting accountable health services.
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Affiliation(s)
- C King
- Institute for Global Health, University College London, 3rd Floor, 30 Guilford Street, London, WC1N 1EH, UK.
| | - C Zamawe
- Parent and Child Health Initiative, Lilongwe, Malawi.
| | - M Banda
- MaiMwana Project, Mchinji, Malawi.
| | - N Bar-Zeev
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi.
- Institute of Infection & Global Health, University of Liverpool, Liverpool, UK.
| | - J Beard
- Institute for Global Health, University College London, 3rd Floor, 30 Guilford Street, London, WC1N 1EH, UK.
- London School of Hygiene and Tropical Medicine, London, UK.
| | - J Bird
- Department of Computer Science, City University London, London, UK.
| | - A Costello
- Institute for Global Health, University College London, 3rd Floor, 30 Guilford Street, London, WC1N 1EH, UK.
| | - P Kazembe
- MaiMwana Project, Mchinji, Malawi.
- Baylor College of Medicine Children's Foundation, Lilongwe, Malawi.
| | - D Osrin
- Institute for Global Health, University College London, 3rd Floor, 30 Guilford Street, London, WC1N 1EH, UK.
| | - E Fottrell
- Institute for Global Health, University College London, 3rd Floor, 30 Guilford Street, London, WC1N 1EH, UK.
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Abstract
Avian malaria parasites of the genus Plasmodium have the ability to cause morbidity and mortality in naïve hosts, and their impact on the native biodiversity is potentially serious. Over the last decade, avian malaria has aroused increasing interest as an emerging disease in New Zealand with some endemic avian species, such as the endangered mohua (Mohua ochrocephala), thought to be particularly susceptible. To date, avian malaria parasites have been found in 35 different bird species in New Zealand and have been diagnosed as causing death in threatened species such as dotterel (Charadrius obscurus), South Island saddleback (Philesturnus carunculatus carunculatus), mohua, hihi (Notiomystis cincta) and two species of kiwi (Apteryx spp.). Introduced blackbirds (Turdus merula) have been found to be carriers of at least three strains of Plasmodium spp. and because they are very commonly infected, they are likely sources of infection for many of New Zealand's endemic birds. The spread and abundance of introduced and endemic mosquitoes as the result of climate change is also likely to be an important factor in the high prevalence of infection in some regions and at certain times of the year. Although still limited, there is a growing understanding of the ecology and epidemiology of Plasmodium spp. in New Zealand. Molecular biology has played an important part in this process and has markedly improved our understanding of the taxonomy of the genus Plasmodium. This review presents our current state of knowledge, discusses the possible infection and disease outcomes, the implications for host behaviour and reproduction, methods of diagnosis of infection, and the possible vectors for transmission of the disease in New Zealand.
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Affiliation(s)
- E R Schoener
- a Institute of Veterinary, Animal and Biomedical Sciences , Massey University , Palmerston North , New Zealand
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Ha HJ, Banda M, Alley MR, Howe L, Gartrell BD. The Seroprevalence of Avipoxvirus and Its Association with Avian Malaria (Plasmodium spp.) Infection in Introduced Passerine Birds in the Southern Regions of the North Island of New Zealand. Avian Dis 2013; 57:109-15. [DOI: 10.1637/10285-061912-resnote.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Plourde PJ, Mphuka S, Muyinda GK, Banda M, Sichali-Sichinga K, Chama D, Ronald AR. Accuracy and costs of rapid human immunodeficiency virus testing technologies in rural hospitals in Zambia. Sex Transm Dis 1998; 25:254-9. [PMID: 9587177 DOI: 10.1097/00007435-199805000-00007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To evaluate the accuracy and costs of newer rapid human immunodeficiency virus (HIV) antibody tests in primary health care settings in rural Zambia. METHODS Three rural hospitals participated in this study. During a baseline assessment period, HIV testing practices were recorded on 250 consecutive clients at each hospital. Baseline evaluation was compared with 250 subsequent consecutive clients tested using a testing algorithm consisting of an initial screening HIV Dipstick test (McDonald Scientific [PVT] Limited, Harare, Zimbabwe) followed by confirmatory testing of all reactive specimens using the HIV Capillus test (Cambridge Diagnostics, Galway, Ireland), in conformity with World Health Organization HIV testing recommendations. Quality control was performed at a national university teaching hospital laboratory. RESULTS A total of 1,500 clients was entered, with an HIV seropositivity rate of 53.2%. Most HIV testing was performed on patients with signs and symptoms suggestive of HIV infection. Same-day results were provided for only 16%. The HIV Dipstick testing algorithm sensitivity was 96.9%, and specificity was 98.0%. Counselor dissatisfaction was greater with the Dipstick algorithm as a result of 5.3% discordant results. Use of the HIV Dipstick testing algorithm cost between US $3.00 and US $3.80 per client tested. CONCLUSIONS The accuracy of HIV testing in unsophisticated rural laboratories in Zambia is acceptable. Although HIV Dipstick testing algorithm costs were relatively high for a developing country, this HIV testing procedure is currently the most economical method available in Zambia. Accurate, less costly HIV testing algorithms are still needed.
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Affiliation(s)
- P J Plourde
- Churches Medical Association of Zambia, Lusaka, Zambia
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Wallner KE, Banda M, Li GC. Hyperthermic enhancement of cell killing by mitomycin C in mitomycin C-resistant Chinese hamster ovary cells. Cancer Res 1987; 47:1308-12. [PMID: 3102043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The interaction of hyperthermia and mitomycin C (MMC) was studied in wild-type Chinese hamster ovary cells and in Chinese hamster ovary cells selected for resistance to MMC. Hyperthermic potentiation of MMC activity was maximal if heating was done simultaneously, or up to 3 h following MMC exposure. Heat enhanced the effect of MMC in both drug-sensitive and -resistant cells. Dose enhancement ratios increased from 1.3-2.0 at 42 degrees C to 2.6-3.8 at 43.5 degrees C and were similar for all cell lines. Cellular uptake of MMC was determined by high pressure liquid chromatography. MMC uptake was similar in the drug-sensitive and -resistant cell lines at 37 degrees C. Hyperthermia (43.5 degrees C) increased cellular uptake of MMC by 78 and 27% in MMC-sensitive and -resistant cell lines. MMC-resistant cells were more sensitive to heat alone at 42, 43, and 44 degrees C. The results suggest that tumor cells that have developed resistance to MMC might be treated effectively with MMC combined with heat to augment the response to MMC. Resistance to MMC may also render tumor cells more sensitive to hyperthermia.
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