XBB.1, BQ1.1 and atypical BA.4.6/XBB.1 recombinants predominate current SARS-CoV-2 Wavelets with flu-like symptoms in Cameroon: A snapshot from genomic surveillance.

As of December 2022, Cameroon had observed a slight resurgence of COVID-19, raising concerns on genomic surveillance of related-SARS-CoV-2 variants under circulation. Following a laboratory-based survey, positive SARS-CoV-2 samples detected from December-2022 through March-2023 were processed for targeted sequencing at the Chantal BIYA International Reference Centre (CIRCB) in Yaoundé-Cameroon. From all positive cases detected, 13 were successfully sequenced (mean age 34 years, 70% female); the majority of the cases were unvaccinated (70%, 9/13) and symptomatic (92%, 12/13); all with flu-like symptoms (100%, 12/12). Following RT-PCR, the median cycle threshold was 22.23 [18-24] for the N gene; and 24.09 [20-26] for the ORF gene, underscoring high viral loads. Phylogenetic analysis of nucleotide sequences identified four major sub-variants in circulation, of which BA.5 (3/13), the recombinants BQ.1.1 (4/13), XBB.1 (4/13) and novel atypical variant of BA.4.6/XBB.1 (2/13). This snapshot surveillance indicates the introduction/emergence and circulation of new Omicron sub-variants, all accompanied by minor/mild symptoms. However, these new sub-variants and recombinants call for continuous genomic surveillance to prevent further resurgence of Covid-19 epidemiological wave.

HIV risk behaviour, viraemia, and transmission across HIV cascade stages including low-level viremia: Analysis of 14 cross-sectional population-based HIV Impact Assessment surveys in sub-Saharan Africa.

As antiretroviral treatment (ART) coverage for people living with HIV (PLHIV) increases, HIV programmes require up-to-date information about evolving HIV risk behaviour and transmission risk, including those with low-level viremia (LLV; >50 to ≤1000 copies/mL), to guide prevention priorities. We aimed to assess differences in sexual risk behaviours, distribution of viral load (VL) and proportion of transmission across PLHIV subgroups. We analysed data from Population-based HIV Impact Assessment surveys in 14 sub-Saharan African countries during 2015-2019. We estimated adjusted prevalence ratios (aPR) of self-reported HIV high-risk behaviour (multiple partners and condomless sex) across cascade stages via generalised estimation equations. We modelled the proportions of transmission from each subgroup using relative self-reported sexual risk, a Hill function for transmission rate by VL, and proportions within cascade stages from surveys and UNAIDS country estimates for 2010-2020. Compared to PLHIV with undetectable VL (≤50 copies/mL), undiagnosed PLHIV (aPR women: 1.28 [95% CI: 1.08-1.52]; men: 1.61 [1.33-1.95]) and men diagnosed but untreated (2.06 [1.52-2.78]) were more likely to self-report high-risk sex. High-risk behaviour was not significantly associated with LLV. Mean VL was similar among undiagnosed, diagnosed but untreated, and on ART but non-suppressed sub-groups. Across surveys, undiagnosed and diagnosed but untreated contributed most to transmission (40-91% and 1-41%, respectively), with less than 1% from those with LLV. Between 2010 and 2020, the proportion of transmission from individuals on ART but non-suppressed increased. In settings with high ART coverage, effective HIV testing, ART linkage, and retention remain priorities to reduce HIV transmission. Persons with LLV are an increasing share of PLHIV but their contribution to HIV transmission was small. Improving suppression among PLHIV on ART with VL ≥1000 copies/mL will become increasingly important.

Seroprevalence of SARS-CoV-2 in 10 Regional Capitals of Cameroon, October-December 2020.

BACKGROUND: Cameroon was among the most affected African countries during the first wave of the COVID-19 pandemic; however, the true prevalence of SARS-CoV-2 remains unknown. METHODS: From October to December 2020, we conducted a cross-sectional, age-stratified SARS-CoV-2 seroepidemiological survey at 30 purposively selected community-based sites across Cameroon's 10 regional capitals, sampling 10,000 individuals aged 5 years or older. We employed a parallel SARS-CoV-2 antibody testing algorithm (WANTAI ELISA and Abbott Architect) to improve both the positive predictive value and negative predictive value of seroprevalence. RESULTS: The overall weighted and adjusted seroprevalence of SARS-CoV-2 antibodies across the 10 urban capitals of Cameroon was 10.5% (95% CI: 9.1%-12.0%) among participants aged ≥5 years. Of the 9332 participants, 730 males (13.1%, 95% CI: 11.5%-14.9%) had SARS-CoV-2 antibodies compared to 293 females (8.0%, 95% CI: 6.8%-9.3%). Among those who reported a comorbidity at the time of testing, 15.8% (95% CI: 12.8%-19.4%) were seropositive. We estimated that over 2 million SARS-CoV-2 infections occurred in the 10 regional capitals of Cameroon between October and December 2020, compared to 21,160 cases officially reported at that time translating to one laboratory-confirmed case being reported for every 110 SARS-CoV-2 infections across the 10 urban capitals. CONCLUSION: This study's findings point to extensive and under-reported circulation of SARS-CoV-2 in Cameroon-an almost 100-fold more cases compared to the number of cases reported to the World Health Organization. This finding highlights the importance of conducting serosurveys, especially in settings where access to testing may be limited and to repeat such surveys as part of pandemic tracking.

Brief Report: Self-Reported HIV-Positive Status but Subsequent HIV-Negative Test Results in Population-Based HIV Impact Assessment Survey Participants-11 Sub-Saharan African Countries, 2015-2018.

BACKGROUND: HIV testing is a critical step to accessing antiretroviral therapy (ART) because early diagnosis can facilitate earlier initiation of ART. This study presents aggregated data of individuals who self-reported being HIV-positive but subsequently tested HIV-negative during nationally representative Population-Based HIV Impact Assessment surveys conducted in 11 countries from 2015 to 2018. METHOD: Survey participants aged 15 years or older were interviewed by trained personnel using a standard questionnaire to determine HIV testing history and self-reported HIV status. Home-based HIV testing and counseling using rapid diagnostic tests with return of results were performed by survey staff according to the respective national HIV testing services algorithms on venous blood samples. Laboratory-based confirmatory HIV testing for all participants identified as HIV-positives and self-reported positives, irrespective of HIV testing results, was conducted and included Geenius HIV-1/2 and DNA polymerase chain reaction if Geenius was negative or indeterminate. RESULTS: Of the 16,630 participants who self-reported as HIV-positive, 16,432 (98.6%) were confirmed as HIV-positive and 198 (1.4%) were HIV-negative by subsequent laboratory-based testing. Participants who self-reported as HIV-positive but tested HIV-negative were significantly younger than 30 years, less likely to have received ART, and less likely to have received a CD4 test compared with participants who self-reported as HIV-positive with laboratory-confirmed infection. CONCLUSIONS: A small proportion of self-reported HIV-positive individuals could not be confirmed as positive, which could be due to initial misdiagnosis, deliberate wrong self-report, or misunderstanding of the questionnaire. As universal ART access is expanding, it is increasingly important to ensure quality of HIV testing and confirmation of HIV diagnosis before ART initiation.

Genomic surveillance of SARS-CoV-2 reveals highest severity and mortality of delta over other variants: evidence from Cameroon.

While the SARS-CoV-2 dynamic has been described globally, there is a lack of data from Sub-Saharan Africa. We herein report the dynamics of SARS-CoV-2 lineages from March 2020 to March 2022 in Cameroon. Of the 760 whole-genome sequences successfully generated by the national genomic surveillance network, 74% were viral sub-lineages of origin and non-variants of concern, 15% Delta, 6% Omicron, 3% Alpha and 2% Beta variants. The pandemic was driven by SARS-CoV-2 lineages of origin in wave 1 (16 weeks, 2.3% CFR), the Alpha and Beta variants in wave 2 (21 weeks, 1.6% CFR), Delta variants in wave 3 (11 weeks, 2.0% CFR), and omicron variants in wave 4 (8 weeks, 0.73% CFR), with a declining trend over time (p = 0.01208). Even though SARS-CoV-2 heterogeneity did not seemingly contribute to the breadth of transmission, the viral lineages of origin and especially the Delta variants appeared as drivers of COVID-19 severity in Cameroon.

Search for Neutron-to-Hidden-Neutron Oscillations in an Ultracold Neutron Beam.

Models that postulate the existence of hidden sectors address contemporary questions, such as the source of baryogenesis and the nature of dark matter. Neutron-to-hidden-neutron oscillations are among the possible mixing processes and have been tested with ultracold neutron storage and passing-through-wall experiments to set constraints on the oscillation period τ_{nn^{'}}. These searches probe the oscillations as a function of the mass splitting due to the neutron-hidden-neutron energy degeneracy. In this work, we present a new limit derived from neutron disappearance in ultracold neutron beam experiments. The overall limit, given by τ_{nn^{'}}>1 s for |δm|∈[2,69] peV(95.45% C.L.), covers the yet unexplored intermediate mass-splitting range and contributes to the ongoing research on hidden sectors.

Risk Factors for Recent HIV Infections among Adults in 14 Countries in Africa Identified by Population-Based HIV Impact Assessment Surveys, 2015-2019.

Identifying persons who have newly acquired HIV infections is critical for characterizing the HIV epidemic direction. We analyzed pooled data from nationally representative Population-Based HIV Impact Assessment surveys conducted across 14 countries in Africa for recent infection risk factors. We included adults 15-49 years of age who had sex during the previous year and used a recent infection testing algorithm to distinguish recent from long-term infections. We collected risk factor information via participant interviews and assessed correlates of recent infection using multinomial logistic regression, incorporating each survey's complex sampling design. Compared with HIV-negative persons, persons with higher odds of recent HIV infection were women, were divorced/separated/widowed, had multiple recent sex partners, had a recent HIV-positive sex partner or one with unknown status, and lived in communities with higher HIV viremia prevalence. Prevention programs focusing on persons at higher risk for HIV and their sexual partners will contribute to reducing HIV incidence.

Point of Care CD4 Testing in National Household Surveys - Results and Quality Indicators from Eleven Population-Based HIV Impact Assessment (PHIA) Surveys.

Population-based HIV Impact Assessments (PHIAs) are national household (HH) surveys that provide HIV diagnosis and CD4 testing with an immediate return of results. Accurate CD4 results improve HIV-positive participants' clinical care and inform the effectiveness of HIV programs. Here, we present CD4 results from the PHIA surveys that were conducted in 11 countries in sub-Saharan Africa between 2015 and 2018. All of the HIV-positive participants and 2 to 5% of the HIV-negative participants were offered Pima CD4 (Abbott, IL, USA) point-of-care (POC) tests. The quality of the CD4 test was ensured by conducting instrument verification, comprehensive training, quality control, a review of testing errors and an analysis of unweighted CD4 data by HIV status, age, gender, and antiretroviral (ARV) treatment status. Overall, CD4 testing was completed for 23,085 (99.5%) of the 23,209 HIV-positive and 7,329 (2.7%) of the 270,741 negative participants in 11 surveys. The instrument error rate was 11.3% (range, 4.4% to 15.7%). The median CD4 values among HIV-positive and HIV-negative participants (aged 15+) were 468 cells/mm3 (interquartile range [IQR], 307 to 654) and 811 cells/mm3 (IQR, 647 to 1,013), respectively. Among the HIV-positive participants (aged 15+), those with detectable ARVs had higher CD4 values (508 cells/mm3) than those with undetectable ARVs (385.5 cells/mm3). Among the HIV-positive participants (aged 15+), 11.4% (2,528/22,253) had a CD4 value of less than 200 cells/mm3, and approximately half of them (1,225/2,528 = 48.5%) had detectable ARVs, whereas 51.5% (1,303/2,528) had no detectable ARVs (P < 0.0001). We successfully implemented high quality POC CD4 testing using Pima instruments. Our data come from nationally representative surveys in 11 countries and provide unique insights regarding the CD4 distribution among HIV-positive individuals as well as the baseline CD4 values among HIV-negative individuals. IMPORTANCE The manuscript describes CD4 levels among HIV-positive individuals and baseline CD4 levels among HIV-negative individuals from 11 sub-Saharan countries, thereby highlighting the importance of CD4 markers in the context of the HIV epidemic. Despite increased ARV access in each country, advanced HIV disease (CD4 < 200 cells/mm3) persists among approximately 11% of HIV-positive individuals. Therefore, it is important that our findings are shared with the scientific community to assist with similar implementations of point-of-care testing and to conduct a review of HIV programmatic gaps.

Building on Capacity Established through US Centers for Disease Control and Prevention Global Health Programs to Respond to COVID-19, Cameroon.

The COVID-19 pandemic has highlighted the need for resilient health systems with the capacity to effectively detect and respond to disease outbreaks and ensure continuity of health service delivery. The pandemic has disproportionately affected resource-limited settings with inadequate health capacity, resulting in disruptions in health service delivery and worsened outcomes for key health indicators. As part of the US government's goal of ensuring health security, the US Centers for Disease Control and Prevention has used its scientific and technical expertise to build health capacity and address health threats globally. We describe how capacity developed through global health programs of the US Centers for Disease Control and Prevention in Cameroon was leveraged to respond to coronavirus disease and maintain health service delivery. The health system strengthening efforts in Cameroon can be applied in similar settings to ensure preparedness for future global public health threats and improve health outcomes.

Contribution of PEPFAR-Supported HIV and TB Molecular Diagnostic Networks to COVID-19 Testing Preparedness in 16 Countries.

The US President's Emergency Plan for AIDS Relief (PEPFAR) supports molecular HIV and tuberculosis diagnostic networks and information management systems in low- and middle-income countries. We describe how national programs leveraged these PEPFAR-supported laboratory resources for SARS-CoV-2 testing during the COVID-19 pandemic. We sent a spreadsheet template consisting of 46 indicators for assessing the use of PEPFAR-supported diagnostic networks for COVID-19 pandemic response activities during April 1, 2020, to March 31, 2021, to 27 PEPFAR-supported countries or regions. A total of 109 PEPFAR-supported centralized HIV viral load and early infant diagnosis laboratories and 138 decentralized HIV and TB sites reported performing SARS-CoV-2 testing in 16 countries. Together, these sites contributed to >3.4 million SARS-CoV-2 tests during the 1-year period. Our findings illustrate that PEPFAR-supported diagnostic networks provided a wide range of resources to respond to emergency COVID-19 diagnostic testing in 16 low- and middle-income countries.

The very large n2EDM magnetically shielded room with an exceptional performance for fundamental physics measurements.

We present the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute, which features an interior cubic volume with each side of length 2.92 m, thus providing an accessible space of 25 m3. The MSR has 87 openings of diameter up to 220 mm for operating the experimental apparatus inside and an intermediate space between the layers for housing sensitive signal processing electronics. The characterization measurements show a remanent magnetic field in the central 1 m3 below 100 pT and a field below 600 pT in the entire inner volume, up to 4 cm to the walls. The quasi-static shielding factor at 0.01 Hz measured with a sinusoidal 2 µT peak-to-peak signal is about 100 000 in all three spatial directions and increases rapidly with frequency to reach 108 above 1 Hz.

The design of the n2EDM experiment: nEDM Collaboration.

We present the design of a next-generation experiment, n2EDM, currently under construction at the ultracold neutron source at the Paul Scherrer Institute (PSI) with the aim of carrying out a high-precision search for an electric dipole moment of the neutron. The project builds on experience gained with the previous apparatus operated at PSI until 2017, and is expected to deliver an order of magnitude better sensitivity with provision for further substantial improvements. An overview is of the experimental method and setup is given, the sensitivity requirements for the apparatus are derived, and its technical design is described.

A Comprehensive Approach to Assuring Quality of Laboratory Testing in HIV Surveys: Lessons Learned From the Population-Based HIV Impact Assessment Project.

BACKGROUND: Conducting HIV surveys in resource-limited settings is challenging because of logistics, limited availability of trained personnel, and complexity of testing. We described the procedures and systems deemed critical to ensure high-quality laboratory data in the population-based HIV impact assessments and large-scale household surveys. METHODS: Laboratory professionals were engaged in every stage of the surveys, including protocol development, site assessments, procurement, training, quality assurance, monitoring, analysis, and reporting writing. A tiered network of household, satellite laboratories, and central laboratories, accompanied with trainings, optimized process for blood specimen collection, storage, transport, and real-time monitoring of specimen quality, and test results at each level proved critical in maintaining specimen integrity and high-quality testing. A plausibility review of aggregate merged data was conducted to confirm associations between key variables as a final quality check for quality of laboratory results. RESULTS: Overall, we conducted a hands-on training for 3355 survey staff across 13 surveys, with 160-387 personnel trained per survey on biomarker processes. Extensive training and monitoring demonstrated that overall, 99% of specimens had adequate volume and 99.8% had no hemolysis, indicating high quality. We implemented quality control and proficiency testing for testing, resolved discrepancies, verified >300 Pima CD4 instruments, and monitored user errors. Aggregate data review for plausibility further confirmed the high quality of testing. CONCLUSIONS: Ongoing engagement of laboratory personnel to oversee processes at all levels of the surveys is critical for successful national surveys. High-quality population-based HIV impact assessments laboratory data ensured reliable results and demonstrated the impact of HIV programs in 13 countries.

HIV-1 Recent Infection Testing Algorithm With Antiretroviral Drug Detection to Improve Accuracy of Incidence Estimates.

BACKGROUND: HIV-1 incidence calculation currently includes recency classification by HIV-1 incidence assay and unsuppressed viral load (VL ≥ 1000 copies/mL) in a recent infection testing algorithm (RITA). However, persons with recent classification not virally suppressed and taking antiretroviral (ARV) medication may be misclassified. SETTING: We used data from 13 African household surveys to describe the impact of an ARV-adjusted RITA on HIV-1 incidence estimates. METHODS: HIV-seropositive samples were tested for recency using the HIV-1 Limiting Antigen (LAg)-Avidity enzyme immunoassay, HIV-1 viral load, ARVs used in each country, and ARV drug resistance. LAg-recent result was defined as normalized optical density values ≤1.5. We compared HIV-1 incidence estimates using 2 RITA: RITA1: LAg-recent + VL ≥ 1000 copies/mL and RITA2: RITA1 + undetectable ARV. We explored RITA2 with self-reported ARV use and with clinical history. RESULTS: Overall, 357 adult HIV-positive participants were classified as having recent infection with RITA1. RITA2 reclassified 55 (15.4%) persons with detectable ARV as having long-term infection. Those with detectable ARV were significantly more likely to be aware of their HIV-positive status (84% vs. 10%) and had higher levels of drug resistance (74% vs. 26%) than those without detectable ARV. RITA2 incidence was lower than RITA1 incidence (range, 0%-30% decrease), resulting in decreased estimated new infections from 390,000 to 341,000 across the 13 countries. Incidence estimates were similar using detectable or self-reported ARV (R2 > 0.995). CONCLUSIONS: Including ARV in RITA2 improved the accuracy of HIV-1 incidence estimates by removing participants with likely long-term HIV infection.

Unawareness of HIV Infection Among Men Aged 15-59 Years in 13 Sub-Saharan African Countries: Findings From the Population-Based HIV Impact Assessments, 2015-2019.

BACKGROUND: Identifying men living with HIV in sub-Saharan Africa (SSA) is critical to end the epidemic. We describe the underlying factors of unawareness among men aged 15-59 years who ever tested for HIV in 13 SSA countries. METHODS: Using pooled data from the nationally representative Population-based HIV Impact Assessments, we fit a log-binomial regression model to identify characteristics related to HIV positivity among HIV-positive unaware and HIV-negative men ever tested for HIV. RESULTS: A total of 114,776 men were interviewed and tested for HIV; 4.4% were HIV-positive. Of those, 33.7% were unaware of their HIV-positive status, (range: 20.2%-58.7%, in Rwanda and Cote d'Ivoire). Most unaware men reported they had ever received an HIV test (63.0%). Age, region, marital status, and education were significantly associated with HIV positivity. Men who had HIV-positive sexual partners (adjusted prevalence ratio [aPR]: 5.73; confidence interval [95% CI]: 4.13 to 7.95) or sexual partners with unknown HIV status (aPR: 2.32; 95% CI: 1.89 to 2.84) were more likely to be HIV-positive unaware, as were men who tested more than 12 months compared with HIV-negative men who tested within 12 months before the interview (aPR: 1.58; 95% CI: 1.31 to 1.91). Tuberculosis diagnosis and not being circumcised were also associated with HIV positivity. CONCLUSION: Targeting subgroups of men at risk for infection who once tested negative could improve yield of testing programs. Interventions include improving partner testing, frequency of testing, outreach and educational strategies, and availability of HIV testing where men are accessing routine health services.

Improving laboratory quality and capacity through leadership and management training: Lessons from Zambia 2016-2018.

BACKGROUND: Competent leadership and management are imperative for delivering quality laboratory services; however, few laboratory managers receive job-specific training in organisational management and leadership. OBJECTIVE: To develop and evaluate participants' competencies in organisational leadership and management as measured through learner and laboratory quality improvement assessments. METHODS: This professional development programme employed a mentored, blended learning approach, utilising in-person didactic and online training, with the practical application of a capstone project in the laboratories. Programme impact was evaluated through a series of pre- and post-laboartory assessments using the Stepwise Laboratory Improvement Process Towards Accreditation checklist, as well as learner-competency assessments through online quizzes and discussions. RESULTS: From 2016 to 2018, 31 managers and quality officers from 16 individual laboratories graduated from the programme having completed capstone projects addressing areas in the entire laboratory testing process. Laboratories increased their compliance with the International Organization for Standardization 15189 standard and all but two laboratories significantly increased their accreditation scores. Two laboratories gained three stars, two laboratories gained two stars, and five laboratories gained one star. Five laboratories subsequently achieved International Organization for Standardization 15189 accreditation in 2019. CONCLUSION: This programme taught leadership theory to laboratory managers and allowed them to implement leadership and management practices in the laboratory setting. Programmes such as this complement existing laboratory quality management training programmes such as Strengthening Laboratory Management Toward Accreditation.

Performance and operational feasibility of antigen and antibody rapid diagnostic tests for COVID-19 in symptomatic and asymptomatic patients in Cameroon: a clinical, prospective, diagnostic accuracy study.

BACKGROUND: Real-time PCR is recommended to detect SARS-CoV-2 infection. However, PCR availability is restricted in most countries. Rapid diagnostic tests are considered acceptable alternatives, but data are lacking on their performance. We assessed the performance of four antibody-based rapid diagnostic tests and one antigen-based rapid diagnostic test for detecting SARS-CoV-2 infection in the community in Cameroon. METHODS: In this clinical, prospective, diagnostic accuracy study, we enrolled individuals aged at least 21 years who were either symptomatic and suspected of having COVID-19 or asymptomatic and presented for screening. We tested peripheral blood for SARS-CoV-2 antibodies using the Innovita (Biological Technology; Beijing, China), Wondfo (Guangzhou Wondfo Biotech; Guangzhou, China), SD Biosensor (SD Biosensor; Gyeonggi-do, South Korea), and Runkun tests (Runkun Pharmaceutical; Hunan, China), and nasopharyngeal swabs for SARS-CoV-2 antigen using the SD Biosensor test. Antigen rapid diagnostic tests were compared with Abbott PCR testing (Abbott; Abbott Park, IL, USA), and antibody rapid diagnostic tests were compared with Biomerieux immunoassays (Biomerieux; Marcy l'Etoile, France). We retrospectively tested two diagnostic algorithms that incorporated rapid diagnostic tests for symptomatic and asymptomatic patients using simulation modelling. FINDINGS: 1195 participants were enrolled in the study. 347 (29%) tested SARS-CoV-2 PCR-positive, 223 (19%) rapid diagnostic test antigen-positive, and 478 (40%) rapid diagnostic test antibody-positive. Antigen-based rapid diagnostic test sensitivity was 80·0% (95% CI 71·0-88·0) in the first 7 days after symptom onset, but antibody-based rapid diagnostic tests had only 26·8% sensitivity (18·3-36·8). Antibody rapid diagnostic test sensitivity increased to 76·4% (70·1-82·0) 14 days after symptom onset. Among asymptomatic participants, the sensitivity of antigen-based and antibody-based rapid diagnostic tests were 37·0% (27·0-48·0) and 50·7% (42·2-59·1), respectively. Cohen's κ showed substantial agreement between Wondfo antibody rapid diagnostic test and gold-standard ELISA (κ=0·76; sensitivity 0·98) and between Biosensor and ELISA (κ=0·60; sensitivity 0·94). Innovita (κ=0·47; sensitivity 0·93) and Runkun (κ=0·43; sensitivity 0·76) showed moderate agreement. An antigen-based retrospective algorithm applied to symptomatic patients showed 94·0% sensitivity and 91·0% specificity in the first 7 days after symptom onset. For asymptomatic participants, the algorithm showed a sensitivity of 34% (95% CI 23·0-44·0) and a specificity of 92·0% (88·0-96·0). INTERPRETATION: Rapid diagnostic tests had good overall sensitivity for diagnosing SARS-CoV-2 infection. Rapid diagnostic tests could be incorporated into efficient testing algorithms as an alternative to PCR to decrease diagnostic delays and onward viral transmission. FUNDING: Médecins Sans Frontières WACA and Médecins Sans Frontières OCG. TRANSLATIONS: For the French and Spanish translations of the abstract see Supplementary Materials section.

Medial minimally invasive helical plate osteosynthesis of the distal femur - a new technique.

INTRODUCTION: The goal of this study was to evaluate distal femoral minimally invasive plate osteosynthesis (MIPO) from a distal medial approach by use of a pre-bent helical implant. MATERIAL & METHODS: A total of 18 lower extremities was evaluated. A 29.6 cm steel plate was constructed and pre-bent on bone specimens with a torsion of 55.7° A 5 cm incision was performed from the tip of the medial epicondyle alongside its centre in a proximal direction. The medial border of the vastus medialis was retracted anteriorly. The level of the proximal skin incision was determined using the length of the pre-bent plates. The proximal incision was performed at a length of 4 cm at the described height at a line between the lateral epicondyle and the tip of the greater trochanter. A raspatory was advanced beneath the vastus medialis in a proximal direction to create an extraperiosteal tunnel for plate insertion. The plate was fixed to the bone at its proximal and distal portion via screws. Following dissection, the distance between the nearest perforator to the proximal plate end was evaluated. The vertical distances between the medial border of the plate and the femoral artery and femoral nerve were measured at the level of the proximal plate end and at the level of the proximal margin of the vastoadductor membrane. RESULTS: The most proximal perforating artery was located at a mean distance of 20.15 mm starting from the proximal plate margin. The mean interval between the medial border of the plate at the level of its proximal tip and the femoral artery was 51.9 mm. The average distance between the femoral nerve and the medial border of the proximal part of the plate was 42.3 mm. Regarding the interval between the medial border of the plate and the femoral artery, this was at a mean of 40.5 mm at the level of the proximal margin of the vastoadductor membrane. During dissection, none of the specimens showed any lesions of the adjacent anatomical characteristics. CONCLUSION: Our results indicate MIPO of the distal femur from a medial approach as a safe technique.