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Finci I, Rojas Castro MY, Hasibra I, Sulo J, Fico A, Daja R, Vasili A, Kota M, Preza I, Mühlemann B, Drosten C, Pebody R, Lafond KE, Kissling E, Katz MA, Bino S. Primary Series and Booster Coronavirus Disease 2019 Vaccine Effectiveness in a Cohort of Healthcare Workers in Albania During a BA.1 and BA.2 Variant Period, January-May 2022. Open Forum Infect Dis 2023; 10:ofad479. [PMID: 37885795 PMCID: PMC10599317 DOI: 10.1093/ofid/ofad479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/19/2023] [Indexed: 10/28/2023] Open
Abstract
Background Healthcare workers (HCWs) have experienced high rates of coronavirus disease 2019 (COVID-19) morbidity and mortality. We estimated COVID-19 2-dose primary series and monovalent booster vaccine effectiveness (VE) against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron (BA.1 and BA.2) infection among HCWs in 3 Albanian hospitals during January-May 2022. Methods Study participants completed weekly symptom questionnaires, underwent polymerase chain reaction (PCR) testing when symptomatic, and provided quarterly blood samples for serology. We estimated VE using Cox regression models (1 - hazard ratio), with vaccination status as the time-varying exposure and unvaccinated HCWs as the reference group, adjusting for potential confounders: age, sex, prior SARS-CoV-2 infection (detected by PCR, rapid antigen test, or serology), and household size. Results At the start of the analysis period, 76% of 1462 HCWs had received a primary series, 10% had received a booster dose, and 9% were unvaccinated; 1307 (89%) HCWs had evidence of prior infection. Overall, 86% of primary series and 98% of booster doses received were BNT162b2. The median time interval from the second dose and the booster dose to the start of the analysis period was 289 (interquartile range [IQR], 210-292) days and 30 (IQR, 22-46) days, respectively. VE against symptomatic PCR-confirmed infection was 34% (95% confidence interval [CI], -36% to 68%) for the primary series and 88% (95% CI, 39%-98%) for the booster. Conclusions Among Albanian HCWs, most of whom had been previously infected, COVID-19 booster dose offered improved VE during a period of Omicron BA.1 and BA.2 circulation. Our findings support promoting booster dose uptake among Albanian HCWs, which, as of January 2023, was only 20%. Clinical Trials Registration. NCT04811391.
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Affiliation(s)
- Iris Finci
- Regional Office for Europe, World Health Organization,Copenhagen, Denmark
| | | | - Iris Hasibra
- Department for the Control of Infectious Diseases, Institute of Public Health, Tirana, Albania
| | - Jonilda Sulo
- Southeast European Center for Surveillance and Control of Infectious Diseases,Tirana, Albania
- Mediterranean and Black Sea Programme in Intervention Epidemiology Training, European Centre for Disease Prevention and Control, Solna, Sweden
| | - Albana Fico
- Department for the Control of Infectious Diseases, Institute of Public Health, Tirana, Albania
- Tirana University Hospital Centre, Tirana, Albania
| | - Rovena Daja
- Department for the Control of Infectious Diseases, Institute of Public Health, Tirana, Albania
| | - Adela Vasili
- Department for the Control of Infectious Diseases, Institute of Public Health, Tirana, Albania
| | - Majlinda Kota
- Department for the Control of Infectious Diseases, Institute of Public Health, Tirana, Albania
| | - Iria Preza
- Country Office Albania, World Health Organization, Tirana, Albania
| | - Barbara Mühlemann
- Institute of Virology, Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health,Berlin, Germany
- German Centre for Infection Research, partner site Charité, Berlin, Germany
| | - Christian Drosten
- Institute of Virology, Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health,Berlin, Germany
- German Centre for Infection Research, partner site Charité, Berlin, Germany
| | - Richard Pebody
- Regional Office for Europe, World Health Organization,Copenhagen, Denmark
| | - Kathryn E Lafond
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | - Mark A Katz
- Regional Office for Europe, World Health Organization,Copenhagen, Denmark
| | - Silvia Bino
- Department for the Control of Infectious Diseases, Institute of Public Health, Tirana, Albania
- Southeast European Center for Surveillance and Control of Infectious Diseases,Tirana, Albania
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Rubin-Smith JE, Castro MYR, Preza I, Hasibra I, Sulo J, Fico A, Daja R, Vasili A, Kota M, Schmid A, Sridhar S, Guseinova A, Boshevska G, Bejtja G, Mühlemann B, Drosten C, Jorgensen P, Pebody R, Kissling E, Lafond KE, Katz MA, Bino S. Primary series COVID-19 vaccine effectiveness among healthcare workers in Albania, February-December 2021. IJID Reg 2023; 8:19-27. [PMID: 37317681 PMCID: PMC10106115 DOI: 10.1016/j.ijregi.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 04/09/2023] [Accepted: 04/11/2023] [Indexed: 06/16/2023]
Abstract
Background Healthcare workers have experienced high rates of morbidity and mortality from coronavirus disease 2019 (COVID-19). Methods A prospective cohort study was conducted in three Albanian hospitals between 19 February and 14 December 2021. All participants underwent polymerase chain reaction (PCR) and serological testing at enrolment, regular serology throughout, and PCR testing when symptomatic.Vaccine effectiveness (VE) against COVID-19 and against all severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections (symptomatic or asymptomatic) was estimated. VE was estimated using a Cox regression model, with vaccination status as a time-varying variable. Findings In total, 1504 HCWs were enrolled in this study; 70% had evidence of prior SARS-CoV-2 infection. VE was 65.1% [95% confidence interval (CI) 37.7-80.5] against COVID-19, 58.2% (95% CI 15.7-79.3) among participants without prior SARS-CoV-2 infection, and 73.6% (95% CI 24.3-90.8) among participants with prior SARS-CoV-2 infection. For BNT162b2 alone, VE was 69.5% (95% CI 44.5-83.2). During the period when the Delta variant was predominant, VE was 67.1% (95% CI 38.3-82.5). VE against SARS-CoV-2 infection for the full study period was 36.9% (95% CI 15.8-52.7). Interpretation This study found moderate primary series VE against COVID-19 among healthcare workers in Albania. These results support the continued promotion of COVID-19 vaccination in Albania, and highlight the benefits of vaccination in populations with high levels of prior infection.
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Affiliation(s)
- Julia E. Rubin-Smith
- Global Health Program, Boston Children's Hospital, Boston, MA, USA
- Division of Emergency Medicine, Boston Children's Hospital, Boston, MA, USA
| | | | - Iria Preza
- Institute of Public Health, Tirana, Albania
| | | | - Jonilda Sulo
- Southeast European Centre for Surveillance and Control of Infectious Disease, Tirana, Albania
| | | | | | | | | | - Alexis Schmid
- Global Health Program, Boston Children's Hospital, Boston, MA, USA
- Division of Emergency Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Shela Sridhar
- Global Health Program, Boston Children's Hospital, Boston, MA, USA
- Department of Global Health Equity, Brigham and Women's Hospital, Boston, MA, USA
| | - Alina Guseinova
- World Health Organization Regional Office for Europe, Copenhagen, Denmark
| | | | - Gazmend Bejtja
- World Health Organization Regional Office for Europe, Copenhagen, Denmark
| | - Barbara Mühlemann
- Institute of Virology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt – Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- German Centre for Infection Research, Partner Site Charité, Berlin, Germany
| | - Christian Drosten
- Institute of Virology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt – Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- German Centre for Infection Research, Partner Site Charité, Berlin, Germany
| | - Pernille Jorgensen
- World Health Organization Regional Office for Europe, Copenhagen, Denmark
| | - Richard Pebody
- World Health Organization Regional Office for Europe, Copenhagen, Denmark
| | | | - Kathryn E. Lafond
- Influenza Division, US Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Mark A. Katz
- World Health Organization Regional Office for Europe, Copenhagen, Denmark
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Jorgensen P, Schmid A, Sulo J, Preza I, Hasibra I, Kissling E, Fico A, Sridhar S, Rubin-Smith JE, Kota M, Vasili A, Daja R, Nika M, Pebody R, Lafond KE, Katz MA, Bino S. Factors associated with receipt of COVID-19 vaccination and SARS-CoV-2 seropositivity among healthcare workers in Albania (February 2021-June 2022): secondary analysis of a prospective cohort study. Lancet Reg Health Eur 2023; 27:100584. [PMID: 37013112 PMCID: PMC9969343 DOI: 10.1016/j.lanepe.2023.100584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/23/2022] [Accepted: 01/03/2023] [Indexed: 03/02/2023]
Abstract
Background Healthcare workers (HCWs) have been disproportionally affected by COVID-19. We investigated factors associated with two- and three-dose COVID-19 vaccine uptake and SARS-CoV-2 seropositivity among 1504 HCWs enrolled (19 February-7 May 2021) in a prospective COVID-19 vaccine effectiveness cohort in Albania through a secondary analysis. Methods We collected sociodemographic, occupational, health, prior SARS-CoV-2 infection, and COVID-19 vaccination data from all HCWs at enrollment. Vaccination status was assessed weekly through June 2022. A serum sample was collected from all participants at enrollment and tested for anti-spike SARS-CoV-2 antibodies. We analyzed HCWs characteristics and outcomes using multivariable logistic regression. Findings By 11 June 2022, 1337 (88.9%) HCWs had received two COVID-19 vaccine doses, of whom 255 (19.1%) received a booster. Factors significantly associated with receiving three doses (adjusted odds ratio (aOR), 95% CIs) were being ≥35 years (35-44 years: 1.76 (1.05-2.97); 45-54 years: 3.11 (1.92-5.05); ≥55 years: 3.38 (2.04-5.59)) and vaccinated against influenza (1.78; 1.20-2.64). Booster dose receipt was lower among females (0.58; 0.41-0.81), previously infected (0.67; 0.48-0.93), nurses and midwives (0.31; 0.22-0.45), and support staff (0.19; 0.11-0.32). Overall 1076 (72%) were SARS-CoV-2 seropositive at enrollment. Nurses and midwifes (1.45; 1.05-2.02), support staff (1.57; 1.03-2.41), and HCWs performing aerosol-generating procedures (AGPs) (1.40; 1.01-1.94) had higher odds of being seropositive, while smokers had reduced odds (0.55; 0.40-0.75). Interpretation In a large cohort of Albanian HCWs, COVID-19 vaccine booster dose uptake was very low, particularly among younger, female, and non-physician HCWs, despite evidence demonstrating the added benefit of boosters in preventing infection and severe disease. Reasons behind these disparities should be explored to develop targeted strategies in order to promote uptake in this critical population. SARS-CoV-2 seroprevalence was higher among non-physicians and HCWs performing APGs. A better understanding of the factors contributing to these differences is needed to inform interventions that could reduce infections in the future. Funding This study was funded by the Task Force for Global Health (US Centers for Disease Control (CDC) cooperative agreement # NU51IP000873) and the World Health Organization, Regional Office for Europe.
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Affiliation(s)
- Pernille Jorgensen
- World Health Organization, Regional Office for Europe, Marmorvej 51, 2100, Copenhagen, Denmark
| | - Alexis Schmid
- Boston Children's Hospital Global Health Program, Boston, MA, USA
| | - Jonilda Sulo
- Southeast European Center for Surveillance and Control of Infectious Diseases, Alexander Moisiut Street N.80, 1001, Tirana, Albania
| | - Iria Preza
- Institute of Public Health, Alexander Moisiut Street N.80, 1001, Tirana, Albania
| | - Iris Hasibra
- Institute of Public Health, Alexander Moisiut Street N.80, 1001, Tirana, Albania
| | | | - Albana Fico
- Institute of Public Health, Alexander Moisiut Street N.80, 1001, Tirana, Albania
| | - Shela Sridhar
- Boston Children's Hospital Global Health Program, Boston, MA, USA
- Brigham and Women's Hospital, Department of Global Health Equity, 651 Huntington Avenue FXB, Building, 7th Floor, Boston, MA, USA
| | | | - Majlinda Kota
- Institute of Public Health, Alexander Moisiut Street N.80, 1001, Tirana, Albania
| | - Adela Vasili
- Institute of Public Health, Alexander Moisiut Street N.80, 1001, Tirana, Albania
| | - Rovena Daja
- Institute of Public Health, Alexander Moisiut Street N.80, 1001, Tirana, Albania
| | - Miljana Nika
- Tirana University Hospital “Mother Theresa”, Dibra Street N.372, 1001, Tirana, Albania
| | - Richard Pebody
- World Health Organization, Regional Office for Europe, Marmorvej 51, 2100, Copenhagen, Denmark
| | - Kathryn E. Lafond
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Mark A. Katz
- World Health Organization, Regional Office for Europe, Marmorvej 51, 2100, Copenhagen, Denmark
| | - Silvia Bino
- Institute of Public Health, Alexander Moisiut Street N.80, 1001, Tirana, Albania
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Sridhar S, Fico A, Preza I, Hatibi I, Sulo J, Kissling E, Daja R, Ibrahim R, Lemos D, Rubin-Smith J, Schmid A, Vasili A, Valenciano M, Jorgensen P, Pebody R, Lafond KE, Katz MA, Bino S. COVID-19 vaccine effectiveness among healthcare workers in Albania (COVE-AL): protocol for a prospective cohort study and cohort baseline data. BMJ Open 2022; 12:e057741. [PMID: 35321895 PMCID: PMC8943479 DOI: 10.1136/bmjopen-2021-057741] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION Critical questions remain about COVID-19 vaccine effectiveness (VE) in real-world settings, particularly in middle-income countries. We describe a study protocol to evaluate COVID-19 VE in preventing laboratory-confirmed SARS-CoV-2 infection in health workers (HWs) in Albania, an upper-middle-income country. METHODS AND ANALYSIS In this 12-month prospective cohort study, we enrolled HWs at three hospitals in Albania. HWs are vaccinated through the routine COVID-19 vaccine campaign. Participants completed a baseline survey about demographics, clinical comorbidities, and infection risk behaviours. Baseline serology samples were also collected and tested against the SARS-CoV-2 spike protein, and respiratory swabs were collected and tested for SARS-CoV-2 by RT-PCR. Participants complete weekly symptom questionnaires and symptomatic participants have a respiratory swab collected, which is tested for SARS-CoV-2. At 3, 6, 9 months and 12 months of the study, serology will be collected and tested for antibodies against the SARS-CoV-2 nucleocapsid protein and spike protein. VE will be estimated using a piecewise proportional hazards model (VE=1-HR). BASELINE DATA From February to May 2021, 1504 HWs were enrolled. The median age was 44 (range: 22-71) and 78% were female. At enrolment, 72% of participants were seropositive for SARS-CoV-2. 56% of participants were vaccinated with one dose, of whom 98% received their first shot within 4 days of enrolment. All HWs received the Pfizer BNT162b2 mRNA COVID-19 vaccine. ETHICS AND DISSEMINATION The study protocol and procedures were reviewed and approved by the WHO Ethical Review Board, reference number CERC.0097A, and the Albanian Institute of Public Health Ethical Review Board, reference number 156. All participants have provided written informed consent to participate in this study. The primary results of this study will be published in a peer-reviewed journal at the time of completion. TRIAL REGISTRATION NUMBER NCT04811391.
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Affiliation(s)
- Shela Sridhar
- Global Health Program, Boston Children's Hospital, Boston, Massachusetts, USA
| | | | - Iria Preza
- Institute of Public Health, Tirana, Albania
| | | | - Jonilda Sulo
- Southeast European Center for Surveillance and Control of Infectious Disease, Tirana, Albania
| | | | | | - Rawi Ibrahim
- World Health Organization Regional Office for Europe, Copenhagen, Denmark
| | - Diogo Lemos
- World Health Organization Regional Office for Europe, Copenhagen, Denmark
| | - Julia Rubin-Smith
- Global Health Program, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Alexis Schmid
- Global Health Program, Boston Children's Hospital, Boston, Massachusetts, USA
| | | | | | - Pernille Jorgensen
- World Health Organization Regional Office for Europe, Copenhagen, Denmark
| | - Richard Pebody
- World Health Organization Regional Office for Europe, Copenhagen, Denmark
| | | | - Mark A Katz
- World Health Organization Regional Office for Europe, Copenhagen, Denmark
| | - Silvia Bino
- Institute of Public Health, Southern European Centre for Surveillance and Control of Infectious Diseases (SECID), Tirana, Albania
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Mersini K, Vasili A, Dervishi M, Kureta E, Robo A, Alla L, Daja R, Tomini E, Kota M, Simaku A, Hatibi I, Sulo J, Fico A, Bino S. Early phase of COVID-19 epidemic in Albania. Int J Infect Dis 2022. [PMCID: PMC8884737 DOI: 10.1016/j.ijid.2021.12.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Mersini K, Sulo J, Agolli L, Vasili A, Musa S, Kunchev A, Mikik V, Humolli I, Kalaveshi A, Crilly J, Crawley A, Bino S. Evaluation of main infectious diseases outbreak detection and response timeliness in Southeast European Region. Int J Infect Dis 2019. [DOI: 10.1016/j.ijid.2018.11.315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Simaku A, Preza I, Nelaj E, Sulo J, Bino S. Knowledge, attitudes, and practice regarding influenza vaccination in pregnant women in Albania. Int J Infect Dis 2019. [DOI: 10.1016/j.ijid.2018.11.326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Crilly J, Sulo J, Mersini K, Xhaferri A, Koreta E, Moci A, Bino S. Spatial and temporal analysis of Hepatitis A cases in fier district, Albania, 1986–2016. Int J Infect Dis 2019. [DOI: 10.1016/j.ijid.2018.11.194] [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: 10/27/2022] Open
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Danquah L, Sulo J, Mersini K, Bino S, Huda N, Adisasmito W, Soebandrio A, Karimuribo E, Sindato C, Beda E, Rweyemamu M, Were W, Lutwama J, Yishai R, Cohen D, Thajeen J, Nyein S, Oo MK, Libel M, Gresham L, Japra N, Burke C, Orefuwa E, Asquith P, Longuet C. Assessment of event based surveillance in cross border areas of six regional networks. Int J Infect Dis 2019. [DOI: 10.1016/j.ijid.2018.11.100] [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: 10/27/2022] Open
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Bino S, Vasili A, Sulo J, Myrseli T, Petrela R, Pipero P, Crilly J. Timeliness for visceral leishmaniasis detection in Albania. Int J Infect Dis 2016. [DOI: 10.1016/j.ijid.2016.11.146] [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: 10/20/2022] Open
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Bino S, Vasili A, Myrseli T, Dikolli E, Mersini K, Alla L, Sulo J, Crilly J, Yotebieng K, Bersani A. One Health approach gap analysis of leishmaniasis detection, prevention, and response in the Republic of Albania. Int J Infect Dis 2016. [DOI: 10.1016/j.ijid.2016.11.370] [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: 10/20/2022] Open
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Sulo J, Chimpeni P, Hatcher J, Kublin JG, Plowe CV, Molyneux ME, Marsh K, Taylor TE, Watkins WM, Winstanley PA. Chlorproguanil-dapsone versus sulfadoxine-pyrimethamine for sequential episodes of uncomplicated falciparum malaria in Kenya and Malawi: a randomised clinical trial. Lancet 2002; 360:1136-43. [PMID: 12387962 DOI: 10.1016/s0140-6736(02)11198-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Chlorproguanil-dapsone exerts lower resistance pressure on Plasmodium falciparum than does sulfadoxine-pyrimethamine, but is rapidly eliminated. We aimed to find out whether chlorproguanil-dapsone results in a higher retreatment rate for malaria than sulfadoxine-pyrimethamine. METHODS In a randomised trial of paediatric outpatients with uncomplicated falciparum malaria, patients received either chlorproguanil-dapsone or sulfadoxine-pyrimethamine and were followed up for up to 1 year. Sites were in Kenya (n=410) and Malawi (n=500). We used per-protocol analysis to assess the primary outcome of annual malaria incidence. FINDINGS Drop-outs were 117 of 410 (28.5%) in Kenya, and 342 of 500 (68.4%) in Malawi. Follow-up was for a median of 338 days (IQR 128-360) and 342 days (152-359) in Kilifi (chlorproguanil-dapsone and sulfadoxine-pyrimethamine, respectively), and for 120 days (33-281) and 84 days (26-224) in Blantyre. Mean annual malaria incidence was 2.5 versus 2.1 in Kenya (relative risk 1.16, 95% CI 0.98-1.37), and 2.2 versus 2.8 in Malawi (0.77, 0.63-0.94). 4.3% versus 12.8%, and 5.4% versus 20.1%, of patients were withdrawn for treatment failure in Kenya and Malawi, respectively. In Kenya haemoglobin concentration of 50 g/L or less caused exit in 6.9% of chlorproguanil-dapsone patients and 1.5% of sulfadoxine-pyrimethamine patients, but most anaemia occurred before re-treatment. In Malawi only one patient exited because of anaemia. INTERPRETATION Despite the rapid elimination of chlorproguanil-dapsone, children treated with this drug did not have a higher incidence of malaria episodes than those treated with sulfadoxine-pyrimethamine. Treatment failure was more common with sulfadoxine-pyrimethamine. Cause of anaemia in Kenya was probably not adverse reaction to chlorproguanil-dapsone, but this observation requires further study.
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Affiliation(s)
- J Sulo
- Centre for Geographical Medicine, Kenya Medical Research Institute, Kilifi, Kenya
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Nzila AM, Mberu EK, Sulo J, Dayo H, Winstanley PA, Sibley CH, Watkins WM. Towards an understanding of the mechanism of pyrimethamine-sulfadoxine resistance in Plasmodium falciparum: genotyping of dihydrofolate reductase and dihydropteroate synthase of Kenyan parasites. Antimicrob Agents Chemother 2000; 44:991-6. [PMID: 10722502 PMCID: PMC89803 DOI: 10.1128/aac.44.4.991-996.2000] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antifolate combination of pyrimethamine (PM) and sulfadoxine (SD) is the last affordable drug combination available for wide-scale treatment of falciparum malaria in Africa. Wherever this combination has been used, drug-resistant parasites have been selected rapidly. A study of PM-SD effectiveness carried out between 1997 and 1999 at Kilifi on the Kenyan coast has shown the emergence of RI and RII resistance to PM-SD (residual parasitemia 7 days after treatment) in 39 out of 240 (16.25%) patients. To understand the mechanism that underlies resistance to PM-SD, we have analyzed the dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) genotypes of 81 patients. Fifty-one samples were obtained, before treatment, from patients who remained parasite free for at least 7 days after treatment. For a further 20 patients, samples were obtained before treatment and again when they returned to the clinic with parasites 7 days after PM-SD treatment. Ten additional isolates were obtained from patients who were parasitemic 7 days after treatment but who were not sampled before treatment. More than 65% of the isolates (30 of 46) in the initial group had wild-type or double mutant DHFR alleles, and all but 7 of the 47 (85%) had wild-type DHPS alleles. In the paired (before and after treatment) samples, the predominant combinations of DHFR and DHPS alleles before treatment were of triple mutant DHFR and double mutant DHPS (41% [7 of 17]) and of double mutant DHFR and double mutant DHPS (29% [5 of 17]). All except one of the posttreatment isolates had triple mutations in DHFR, and most of these were "pure" triple mutants. In these isolates, the combination of a triple mutant DHFR and wild-type DHPS was detected in 6 of 29 cases (20.7%), the combination of a triple mutant DHFR and a single mutant (A437G) DHPS was detected in 4 of 29 cases (13.8%), and the combination of a triple mutant DHFR and a double mutant (A437G, L540E) DHPS was detected in 16 of 29 cases (55.2%). These results demonstrate that the triply mutated allele of DHFR with or without mutant DHPS alleles is associated with RI and RII resistance to PM-SD. The prevalence of the triple mutant DHFR-double mutant DHPS combination may be an operationally useful marker for predicting the effectiveness of PM-SD as a new malaria treatment.
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Affiliation(s)
- A M Nzila
- Kenya Medical Research Institute/Wellcome Trust Collaborative Research Program, Wellcome Trust Research Laboratories, Nairobi, UK.
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