Journal Article > ResearchFull Text
Vaccine. 2022 June 9; Volume S0264-410X (Issue 22); 00552-7.; DOI:10.1016/j.vaccine.2022.04.093
Lightowler M, Manangazira P, Nackers F, Van Herp M, Phiri I, et al.
Vaccine. 2022 June 9; Volume S0264-410X (Issue 22); 00552-7.; DOI:10.1016/j.vaccine.2022.04.093
BACKGROUND
Zimbabwe suffers from regular outbreaks of typhoid fever (TF), worse since 2017. Most cases were in Harare and a vaccination campaign with Typhoid Conjugate Vaccine (TCV) was conducted in March 2019. The vaccine effectiveness (VE) was assessed against culture-confirmed S. Typhi in children six months to 15 years and in individuals six months to 45 years in Harare.
METHODS
A matched case-control study was conducted in three urban suburbs of Harare targeted by the TCV vaccination campaign. Suspected TF cases were enrolled prospectively in four health facilities and were matched to facility (1:1) and community (1:5) controls.
FINDINGS
Of 504 suspected cases from July 2019 to March 2020, 148 laboratory-confirmed TF cases and 153 controls confirmed-negative were identified. One hundred and five (47 aged six months to 15 years) cases were age, sex, and residence matched with 105 facility-based controls while 96 cases were matched 1:5 by age, sex, and immediate-neighbour with 229 community controls.
The adjusted VE against confirmed TF was 75% (95%CI: 1–94, p = 0.049) compared to facility controls, and 84% (95%CI: 57–94, p < 0.001) compared to community controls in individuals six months to 15 years. The adjusted VE against confirmed TF was 46% (95%CI: 26–77, p = 0.153) compared to facility controls, and 67% (95%CI: 35–83, p = 0.002) compared to community controls six months to 45 years old.
INTERPRETATION
This study confirms that one vaccine dose of TCV is effective to control TF in children between six months and 15 years old in an African setting.
Zimbabwe suffers from regular outbreaks of typhoid fever (TF), worse since 2017. Most cases were in Harare and a vaccination campaign with Typhoid Conjugate Vaccine (TCV) was conducted in March 2019. The vaccine effectiveness (VE) was assessed against culture-confirmed S. Typhi in children six months to 15 years and in individuals six months to 45 years in Harare.
METHODS
A matched case-control study was conducted in three urban suburbs of Harare targeted by the TCV vaccination campaign. Suspected TF cases were enrolled prospectively in four health facilities and were matched to facility (1:1) and community (1:5) controls.
FINDINGS
Of 504 suspected cases from July 2019 to March 2020, 148 laboratory-confirmed TF cases and 153 controls confirmed-negative were identified. One hundred and five (47 aged six months to 15 years) cases were age, sex, and residence matched with 105 facility-based controls while 96 cases were matched 1:5 by age, sex, and immediate-neighbour with 229 community controls.
The adjusted VE against confirmed TF was 75% (95%CI: 1–94, p = 0.049) compared to facility controls, and 84% (95%CI: 57–94, p < 0.001) compared to community controls in individuals six months to 15 years. The adjusted VE against confirmed TF was 46% (95%CI: 26–77, p = 0.153) compared to facility controls, and 67% (95%CI: 35–83, p = 0.002) compared to community controls six months to 45 years old.
INTERPRETATION
This study confirms that one vaccine dose of TCV is effective to control TF in children between six months and 15 years old in an African setting.
Journal Article > ResearchFull Text
PLOS One. 2020 April 3; Volume 15 (Issue 4); e0230453.; DOI:10.1371/journal.pone.0230453.
Ndlovu Z, Massaquoi L, Bangwen NE, Batumba JN, Bora RU, et al.
PLOS One. 2020 April 3; Volume 15 (Issue 4); e0230453.; DOI:10.1371/journal.pone.0230453.
BACKGROUND
In sub-Saharan Africa, a third of people starting antiretroviral therapy and majority of patients returning to HIV-care after disengagement, present with advanced HIV disease (ADH), and are at high risk of mortality. Simplified and more affordable point-of-care (POC) diagnostics are required to increase access to prompt CD4 cell count screening for ambulatory and asymptomatic patients. The Visitect CD4 Lateral Flow Assay (LFA) is a disposable POC test, providing a visually interpreted result of above or below 200 CD4cells/mm3. This study evaluated the diagnostic performance of this index test.
METHODS
Consenting patients above 18years of age and eligible for CD4 testing were enrolled in Nsanje district hospital (Malawi), Gutu mission hospital (Zimbabwe) and Centre hopitalier de Kabinda (DRC). A total of 708 venous blood samples were tested in the index test and in the BD FACSCount assay (reference test method) in the laboratories (Phase 1) to determine diagnostic accuracy. A total of 433 finger-prick (FP) samples were tested on the index test at POC by clinicians (Phase 2) and a self-completed questionnaire was administered to all testers to explore usability of the index test.
RESULTS
Among 708 patients, 67.2% were female and median CD4 was 297cells/mm3. The sensitivity of the Visitect CD4 LFA using venous blood in the laboratory was 95.0% [95% CI: 91.3-97.5] and specificity was 81.9% [95% CI: 78.2-85.2%]. Using FP samples, the sensitivity of the Visitect CD4 LFA was 98.3% [95% CI: 95.0-99.6] and specificity was 77.2% [95% CI: 71.6-82.2%]. Usability of the Visitect CD4 LFA was high across the study sites with 97% successfully completed tests. Due to the required specific multiple incubation and procedural steps during the Visitect CD4 LFA testing, few health workers (7/26) were not confident to manage testing whilst multi-tasking in their clinical work.
CONCLUSIONS
Visitect CD4 LFA is a promising test for decentralized CD4 screening in resource-limited settings, without access to CD4 testing and and it can trigger prompt management of patients with AHD. Lay health cadres should be considered to conduct Visitect CD4 LFA testing in PHCs as well as coordinating all other POC quality assurance.
In sub-Saharan Africa, a third of people starting antiretroviral therapy and majority of patients returning to HIV-care after disengagement, present with advanced HIV disease (ADH), and are at high risk of mortality. Simplified and more affordable point-of-care (POC) diagnostics are required to increase access to prompt CD4 cell count screening for ambulatory and asymptomatic patients. The Visitect CD4 Lateral Flow Assay (LFA) is a disposable POC test, providing a visually interpreted result of above or below 200 CD4cells/mm3. This study evaluated the diagnostic performance of this index test.
METHODS
Consenting patients above 18years of age and eligible for CD4 testing were enrolled in Nsanje district hospital (Malawi), Gutu mission hospital (Zimbabwe) and Centre hopitalier de Kabinda (DRC). A total of 708 venous blood samples were tested in the index test and in the BD FACSCount assay (reference test method) in the laboratories (Phase 1) to determine diagnostic accuracy. A total of 433 finger-prick (FP) samples were tested on the index test at POC by clinicians (Phase 2) and a self-completed questionnaire was administered to all testers to explore usability of the index test.
RESULTS
Among 708 patients, 67.2% were female and median CD4 was 297cells/mm3. The sensitivity of the Visitect CD4 LFA using venous blood in the laboratory was 95.0% [95% CI: 91.3-97.5] and specificity was 81.9% [95% CI: 78.2-85.2%]. Using FP samples, the sensitivity of the Visitect CD4 LFA was 98.3% [95% CI: 95.0-99.6] and specificity was 77.2% [95% CI: 71.6-82.2%]. Usability of the Visitect CD4 LFA was high across the study sites with 97% successfully completed tests. Due to the required specific multiple incubation and procedural steps during the Visitect CD4 LFA testing, few health workers (7/26) were not confident to manage testing whilst multi-tasking in their clinical work.
CONCLUSIONS
Visitect CD4 LFA is a promising test for decentralized CD4 screening in resource-limited settings, without access to CD4 testing and and it can trigger prompt management of patients with AHD. Lay health cadres should be considered to conduct Visitect CD4 LFA testing in PHCs as well as coordinating all other POC quality assurance.
Conference Material > Abstract
Ronoh Y, Some D, Ortuno R, Kuwenyi K, Mupepe T, et al.
MSF Scientific Days International 2020: Research. 2020 May 20
INTRODUCTION
Cervical cancer is now largely a preventable disease; however, implementation of highly sensitive molecular screening technologies in low-resource settings is partly hindered by the need for intensive investment in equipment and highly trained, skilled laboratory personnel. Resource limitations often preclude the possibility of same-day screening and treatment, as recommend by WHO. We sought to assess the diagnostic accuracy of self-collected versus nurse-collected high vaginal samples (HVS) for human papillomavirus (HPV) screening using GeneXpert, for within-country validation and to further inform its scale-up within routine point-of-care testing in primary healthcare systems.
METHODS
Consenting women presenting for routine cervical screening in selected health facilities in Gutu District, Zimbabwe, were asked to provide three HVS obtained at the same time on a single visit; the first, self-collected, and the following two, nurse-collected. Nurse-collected HVS were tested with GeneXpert (Cepheid, Sunnyvale, USA) and Cobas HPV (Roche, Pleasanton, USA; used as the reference test), whilst self-collected HVS were tested only using GeneXpert. Those testing positive on the reference test were offered visual inspection with acetic acid and cervicography (VIAC). Women with a positive VIAC examination were offered cryotherapy or loop electrosurgical excision procedure.
ETHICS
This study was approved by the MSF Ethics Review Board.
RESULTS
279 participants consented to provide HVS; none reported discomfort or side effects during or after swabbing. Among nurse-collected HVS, 11/279 participants were found positive on genotyping for HPV-16 using Cobas HPV, and nine of 279 were positive using GeneXpert. Eight out of 279 were identified on genotyping for HPV-18/45 using both platforms. The sensitivities of testing for HPV-16 and 18/45 using GeneXpert as compared to the reference test, Cobas, were 89% (95%CI 53-100) and 63% (95%CI 25-92) respectively. The sensitivity of self- and nurse-collected HVS for HPV-16 tested using GeneXpert, as compared to the reference test, was 89% (eight of nine; 95%CI 52-100). Specificity was 100% (95%CI 97-100), with a positive predictive value of 89% (95%CI 52-100), and negative predictive value of 100% (95%CI 97-100). However, sensitivity for detection of HPV-18/45 was 68.3% (95%CI 34-100).
CONCLUSION
Performance of cervical cancer screening using self-collected HVS tested with GeneXpert is comparable to that with nurse-collected HVS. Integrated GeneXpert platforms are already in wide use, enabling rapid diagnosis of tuberculosis, detection of HIV viral load, and early infant diagnosis of HIV, using a single piece of equipment. Deploying GeneXpert for HPV screening using self-collected HVS could help to provide timely results, especially in settings where VIAC is unavailable.
Cervical cancer is now largely a preventable disease; however, implementation of highly sensitive molecular screening technologies in low-resource settings is partly hindered by the need for intensive investment in equipment and highly trained, skilled laboratory personnel. Resource limitations often preclude the possibility of same-day screening and treatment, as recommend by WHO. We sought to assess the diagnostic accuracy of self-collected versus nurse-collected high vaginal samples (HVS) for human papillomavirus (HPV) screening using GeneXpert, for within-country validation and to further inform its scale-up within routine point-of-care testing in primary healthcare systems.
METHODS
Consenting women presenting for routine cervical screening in selected health facilities in Gutu District, Zimbabwe, were asked to provide three HVS obtained at the same time on a single visit; the first, self-collected, and the following two, nurse-collected. Nurse-collected HVS were tested with GeneXpert (Cepheid, Sunnyvale, USA) and Cobas HPV (Roche, Pleasanton, USA; used as the reference test), whilst self-collected HVS were tested only using GeneXpert. Those testing positive on the reference test were offered visual inspection with acetic acid and cervicography (VIAC). Women with a positive VIAC examination were offered cryotherapy or loop electrosurgical excision procedure.
ETHICS
This study was approved by the MSF Ethics Review Board.
RESULTS
279 participants consented to provide HVS; none reported discomfort or side effects during or after swabbing. Among nurse-collected HVS, 11/279 participants were found positive on genotyping for HPV-16 using Cobas HPV, and nine of 279 were positive using GeneXpert. Eight out of 279 were identified on genotyping for HPV-18/45 using both platforms. The sensitivities of testing for HPV-16 and 18/45 using GeneXpert as compared to the reference test, Cobas, were 89% (95%CI 53-100) and 63% (95%CI 25-92) respectively. The sensitivity of self- and nurse-collected HVS for HPV-16 tested using GeneXpert, as compared to the reference test, was 89% (eight of nine; 95%CI 52-100). Specificity was 100% (95%CI 97-100), with a positive predictive value of 89% (95%CI 52-100), and negative predictive value of 100% (95%CI 97-100). However, sensitivity for detection of HPV-18/45 was 68.3% (95%CI 34-100).
CONCLUSION
Performance of cervical cancer screening using self-collected HVS tested with GeneXpert is comparable to that with nurse-collected HVS. Integrated GeneXpert platforms are already in wide use, enabling rapid diagnosis of tuberculosis, detection of HIV viral load, and early infant diagnosis of HIV, using a single piece of equipment. Deploying GeneXpert for HPV screening using self-collected HVS could help to provide timely results, especially in settings where VIAC is unavailable.
Conference Material > Poster
Ngwa W, Manangazira P, Some D, Ortuno R, Ronoh Y, et al.
MSF Scientific Days International 2021: Research. 2021 May 18
Conference Material > Slide Presentation
Ronoh Y, Some D, Ortuno R, Kuwenyi K, Mupepe T, et al.
MSF Scientific Days International 2020: Research. 2020 May 13
Other > Pre-Print
medRxiv. 2022 March 31; DOI:10.1101/2022.03.28.22273032
Lightowler M, Manangazira P, Nackers F, Van Herp M, Phiri I, et al.
medRxiv. 2022 March 31; DOI:10.1101/2022.03.28.22273032
BACKGROUND
Zimbabwe suffers from regular outbreaks of typhoid fever (TF), worse since 2017. Most cases were in Harare and a vaccination campaign with Typhoid Conjugate Vaccine (TCV) was conducted in March 2019. The vaccine effectiveness (VE) was assessed against culture-confirmed S. Typhi in children six months to 15 years and in individuals six months to 45 years in Harare.
METHODS
A matched case-control study was conducted in three urban suburbs of Harare targeted by the TCV vaccination campaign. Suspected TF cases were enrolled prospectively in four health facilities and were matched to facility (1:1) and community (1:5) controls.
FINDINGS
Of 504 suspected cases from July 2019 to March 2020, 148 laboratory-confirmed TF cases and 153 controls confirmed-negative were identified. One hundred and five (47 aged six months to 15 years) cases were age, sex, and residence matched with 105 facility-based controls while 96 cases were matched 1:5 by age, sex, and immediate-neighbour with 229 community controls.
The adjusted VE against confirmed TF was 75% (95%CI: 1–94, p=0.049) compared to facility controls, and 84% (95%CI: 57–94, p<0.001) compared to community controls in individuals six months to 15 years. The adjusted VE against confirmed TF was 46% (95%CI: 26–77, p=0.153) compared to facility controls, and 67% (95%CI: 35–83, p=0.002) compared to community controls six months to 45 years old.
INTERPRETATION
This study confirms that one vaccine dose of TCV is effective to control TF in children between six months and 15 years old in an African setting.
Zimbabwe suffers from regular outbreaks of typhoid fever (TF), worse since 2017. Most cases were in Harare and a vaccination campaign with Typhoid Conjugate Vaccine (TCV) was conducted in March 2019. The vaccine effectiveness (VE) was assessed against culture-confirmed S. Typhi in children six months to 15 years and in individuals six months to 45 years in Harare.
METHODS
A matched case-control study was conducted in three urban suburbs of Harare targeted by the TCV vaccination campaign. Suspected TF cases were enrolled prospectively in four health facilities and were matched to facility (1:1) and community (1:5) controls.
FINDINGS
Of 504 suspected cases from July 2019 to March 2020, 148 laboratory-confirmed TF cases and 153 controls confirmed-negative were identified. One hundred and five (47 aged six months to 15 years) cases were age, sex, and residence matched with 105 facility-based controls while 96 cases were matched 1:5 by age, sex, and immediate-neighbour with 229 community controls.
The adjusted VE against confirmed TF was 75% (95%CI: 1–94, p=0.049) compared to facility controls, and 84% (95%CI: 57–94, p<0.001) compared to community controls in individuals six months to 15 years. The adjusted VE against confirmed TF was 46% (95%CI: 26–77, p=0.153) compared to facility controls, and 67% (95%CI: 35–83, p=0.002) compared to community controls six months to 45 years old.
INTERPRETATION
This study confirms that one vaccine dose of TCV is effective to control TF in children between six months and 15 years old in an African setting.