Country adoption of WHO 2019 guidance on HIV testing strategies and algorithms: a policy review across the WHO African region.

OBJECTIVES: In 2019, the WHO released guidelines on HIV testing service (HTS). We aim to assess the adoption of six of these recommendations on HIV testing strategies among African countries. DESIGN: Policy review. SETTING: 47 countries within the WHO African region. PARTICIPANTS: National HTS policies from the WHO African region as of December 2021. PRIMARY AND SECONDARY OUTCOME MEASURES: Uptake of WHO recommendations across national HTS policies including the standard three-test strategy; discontinuation of a tiebreaker test to rule in HIV infection; discontinuation of western blotting (WB) for HIV diagnosis; retesting prior to antiretroviral treatment (ART) initiation and the use of dual HIV/syphilis rapid diagnostic tests (RDTs) in antenatal care. Country policy adoption was assessed on a continuum, based on varying levels of complete adoption. RESULTS: National policies were reviewed for 96% (n=45/47) of countries in the WHO African region, 38% (n=18) were published before 2019 and 60% (n=28) adopted WHO guidance. Among countries that had not fully adopted WHO guidance, not yet adopting a three-test strategy was the most common reason for misalignment (45%, 21/47); of which 31% and 22% were in low-prevalence (<5%) and high-prevalence (≥5%) countries, respectively. Ten policies (21%) recommended the use of WB and 49% (n=23) recommended retesting before ART initiation. Dual HIV/syphilis RDTs were recommended in 45% (n=21/47) of policies. CONCLUSIONS: Many countries in the African region have adopted WHO-recommended HIV testing strategies; however, efforts are still needed to fully adopt WHO guidance. Countries should accelerate their efforts to adopt and implement a three-test strategy, retesting prior to ART initiation and the use of dual HIV/syphilis RDTs.

Demonstration of the diagnostic agreement of capillary and venous blood samples, using hepatitis-C virus SD Bioline© rapid test: A clinic-based study.

BACKGROUND: Simplifying hepatitis C virus (HCV) screening is a key step in achieving the elimination of HCV as a global public health threat by 2030. OBJECTIVES: The objective of this study was to demonstrate the agreement of capillary blood and venipuncture specimens when using SD Bioline© HCV, a low-cost rapid diagnostic test (RDT), prequalified by WHO in 2016 on venous blood samples. STUDY DESIGN: Recruitment was conducted prospectively among adult patients presenting for HCV testing at the Médecins Sans Frontières (MSF) clinic of Preah Kossamak Hospital (Phnom Penh, Cambodia) between October and November 2017. Capillary and venous blood samples were collected from consenting patients and tested with SD Bioline© HCV. Two independent, blinded readers, and in the case of disagreement, a third reader, interpreted the results of each blood sample. Concordance between results was compared using Cohen's Kappa interrater reliability statistic. Discrepant sample pairs were tested with an enzyme immunoassay, the reference standard, at the Institute Pasteur of Cambodia. RESULTS: Among 421 pairs of samples collected, reader disagreement occurred for 0.7% (n = 3) of the participants. Sixty-four percent of capillary and venous blood sample pairs tested positive for HCV, with a Kappa statistic of 0.985 between the two methods. Three participants with discrepant sample pair results tested positive with EIA. CONCLUSIONS: Capillary and venous blood samples were concordant when tested with HCV SD Bioline© in a clinical context. This simplified testing approach is essential to the scale-up of HCV screening and useful in resource-limited settings or among populations for whom venipuncture is problematic.

Field evaluation of GeneXpert® (Cepheid) HCV performance for RNA quantification in a genotype 1 and 6 predominant patient population in Cambodia.

GeneXpert® (Cepheid) is the only WHO prequalified platform for hepatitis C virus (HCV) nucleic acid amplification testing that is suitable for point-of-care use in resource-limited contexts. However, its application is constrained by the lack of evidence on genotype 6 (GT6) HCV. We evaluated its field performance among a patient population in Cambodia predominantly infected with GT6. Between August and September 2017, we tested plasma samples obtained from consenting patients at Médecins Sans Frontières' HCV clinic at Preah Kossamak Hospital for HCV viral load (VL) using GeneXpert® and compared its results to those obtained using COBAS® AmpliPrep/Cobas® TaqMan® HCV Quantitative Test, v2.0 (Roche) at the Institut Pasteur du Cambodge. Among 769 patients, 77% of the seropositive patients (n = 454/590) had detectable and quantifiable VL using Roche and 43% (n = 195/454) were GT6. The sensitivity and specificity of GeneXpert® against Roche were 100% (95% CI 99.2, 100.0) and 98.5% (95% CI 94.8, 99.8). The mean VL difference was -0.01 (95% CI -0.05, 0.02) log10  IU/mL for 454 samples quantifiable on Roche and -0.07 (95% CI -0.12, -0.02) log10  IU/mL for GT6 (n = 195). The limit of agreement (LOA) was -0.76 to 0.73 log10  IU/mL for all GTs and -0.76 to 0.62 log10 IU/mL for GT6. Twenty-nine GeneXpert® results were outside the LOA. Frequency of error and the median turnaround time (TAT) for GeneXpert® were 1% and 0 days (4 days using Roche). We demonstrated that the GeneXpert® HCV assay has good sensitivity, specificity, quantitative agreement, and TAT in a real-world, resource-limited clinical setting among GT6 HCV patients.

Dual screen and confirm rapid test does not reduce overtreatment of syphilis in pregnant women living in a non-venereal treponematoses endemic region: a field evaluation among antenatal care attendees in Burkina Faso.

OBJECTIVES: In resource-limited settings, screening pregnant women for syphilis using rapid diagnostic tests (RDTs) is a key tool in the prevention of congenital syphilis. However, most syphilis RDTs detect only treponemal antibodies (T-RDT), meaning antibiotics may be provided unnecessarily to previously treated pregnant women, particularly in non-venereal treponematoses endemic regions. We estimated the potential reduction in overtreatment when comparing T-RDT (SD Bioline) to a newer rapid test (Dual Path Platform (DPP) Screen and Confirm Assay, Chembio) detecting both treponemal and non-treponemal antibodies. METHODS: Pregnant women in Déou, Burkina Faso, screened for syphilis during antenatal care (ANC) visits were prospectively enrolled in the study after providing consent. DPP and T-RDT tests were performed on whole blood specimens. Plasma was tested in an international reference laboratory by Treponema pallidum passive particle agglutination (TPPA) and quantitative rapid plasma reagin (RPR). Presumptive active syphilis was defined as a result that was both TPPA and RPR reactive. RESULTS: Of the 242 pregnant women included in the study, 91 (37.6%) had presumptive active syphilis and 19.0% had RPR titres ≥8. DPP testing did not reduce the number of pregnant women who would have been overtreated compared with T-RDT (0.0% vs 2.5%; p=0.218) and had a higher proportion of underdiagnosis (48.4% vs 2.2%; p<0.001). Seven women with high RPR titres ≥8 would not have received treatment had only DPP testing been used. CONCLUSION: In the first evaluation comparing DPP with traditional screening methods in pregnant women, we saw no reduction in unnecessarily treated syphilis and an underestimation of those needing treatment. High seroprevalence in the population may indicate the presence of other treponemal infections in the area, and further study of DPP in a variety of Sahelian and other contexts is warranted.

Four years of case-based surveillance of meningitis following the introduction of MenAfriVac in Moissala, Chad: lessons learned.

OBJECTIVE: Case-based surveillance of bacterial meningitis in sentinel districts has been recommended after the introduction of the conjugated vaccine against Neisseria meningitidis serogroup A (NmA), MenAfriVac, in the African meningitis belt. Here we report data and lessons learnt from four years of surveillance in the district of Moissala, Chad. METHODS: All suspected cases of meningitis were referred free of charge to the district hospital for lumbar puncture and treatment. Cerebrospinal fluid samples were tested with Pastorex latex agglutination in Moissala, and inoculated trans-isolate media were used for culture and PCR at the national reference laboratory and/or at the Norwegian Institute of Public Health. RESULTS: From July 2012 to December 2016, 237 suspected cases of meningitis were notified, and a specimen was collected from 224. Eighty-three samples were positive for a bacterial pathogen by culture, PCR or Pastorex, including 58 cases due to Streptococcus pneumoniae with only 28 of 49 pneumococcal meningitis confirmed by culture or PCR correctly identified by Pastorex. Four cases of NmA were detected by Pastorex, but none were confirmed by PCR. CONCLUSION: Implementation of case-based surveillance for meningitis is feasible in Chad, but has required political and technical engagement. Given the high proportion of S. pneumoniae and its poor detection by Pastorex, continued use of PCR is warranted for surveillance outside of outbreaks, and efforts to accelerate the introduction of pneumococcal conjugate vaccines are needed. Introduction of MenAfriVac in routine immunisation and future availability of a pentavalent meningococcal conjugate vaccine will be key elements for the sustained reduction in meningitis outbreaks in the area.