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.

[Profile and antibiotic susceptibility pattern of bacterial pathogens associated with diarrheas in patients presenting at the Kousseri Regional Hospital Anne, Far North, Cameroon]. / Profil et antibiosensibilité des bactéries pathogènes associées aux diarrhées chez les patients consultant à l'Hôpital Régional Annexe de Kousseri, Extrême-Nord Cameroun.

INTRODUCTION: In most of the health facilities in Cameroon, the management of patients with diarrhea is based on presumptive diagnosis due to limited laboratory resources. This study aimed to determine germs profile and their susceptibility to antibiotics usually prescribed against pathogenic bacteria associated with diarrheas at the Kousseri Regional Hospital Annex from July to October 2015. METHODS: We conducted a descriptive and cross-sectional study of all consenting individual presenting with diarrhea to the Kousseri Regional Hospital Annex during the study period. Stool samples were collected from each patient. Patient data were collected via anonymous questionnaire with face to face interview. Each stool sample was grown on media for enterobacteria and analyzed following the standard stool culture method. The sensitivity of the isolated strains to the most frequently prescribed antibiotics was assessed and the proportions of patients with each pathogen germ and of germ sensitive to each antibiotic were estimated. RESULTS: Out of 150 patients with diarrhea included in the study 45(30.0%) had enteropathogenic bacteria, of which 37(82.2%) in children aged 0-5 years. Escherichia coli was the the most common bacterium(30 cases, 66%) followed by Salmonella spp(7 cases, 16%), Vibrio spp,(5 cases, 11%), Aeromonas spp(2 cases, 4%), and Shigella spp(1 cases, 2%). Susceptibility tests were performed which showed that 17(56.7%), 14(46.7%) and 5(16.7%) E. coli were susceptible to ciprofloxacin, ceftriaxone, cotrimoxazole respectively; 4(57.14%), 2(28.57%) Salmonella spp. were susceptible to ceftriaxone and cotrimoxazole respectively. CONCLUSION: Nearly a third of the cases of diarrheas at the Kousseri Regional Hospital Annex in the season of rain were associated with at least a pathogenic bacterium. The susceptibility of isolated germs to commonly prescribed antibiotics was very limited. Health staff in the facilities in the extreme north of Cameroon prescribe antibiotic against diarrheas on the basis of presumptive diagnosis. Hence, the necessity to implement a system for the monitoring of the associated germ profile and of their susceptibility to commonly prescribed antibiotics.

Predictors of poor retention on antiretroviral therapy as a major HIV drug resistance early warning indicator in Cameroon: results from a nationwide systematic random sampling.

BACKGROUND: Retention on lifelong antiretroviral therapy (ART) is essential in sustaining treatment success while preventing HIV drug resistance (HIVDR), especially in resource-limited settings (RLS). In an era of rising numbers of patients on ART, mastering patients in care is becoming more strategic for programmatic interventions. Due to lapses and uncertainty with the current WHO sampling approach in Cameroon, we thus aimed to ascertain the national performance of, and determinants in, retention on ART at 12 months. METHODS: Using a systematic random sampling, a survey was conducted in the ten regions (56 sites) of Cameroon, within the "reporting period" of October 2013-November 2014, enrolling 5005 eligible adults and children. Performance in retention on ART at 12 months was interpreted following the definition of HIVDR early warning indicator: excellent (>85%), fair (85-75%), poor (<75); and factors with p-value < 0.01 were considered statistically significant. RESULTS: Majority (74.4%) of patients were in urban settings, and 50.9% were managed in reference treatment centres. Nationwide, retention on ART at 12 months was 60.4% (2023/3349); only six sites and one region achieved acceptable performances. Retention performance varied in reference treatment centres (54.2%) vs. management units (66.8%), p < 0.0001; male (57.1%) vs. women (62.0%), p = 0.007; and with WHO clinical stage I (63.3%) vs. other stages (55.6%), p = 0.007; but neither for age (adults [60.3%] vs. children [58.8%], p = 0.730) nor for immune status (CD4351-500 [65.9%] vs. other CD4-staging [59.86%], p = 0.077). CONCLUSIONS: Poor retention in care, within 12 months of ART initiation, urges active search for lost-to-follow-up targeting preferentially male and symptomatic patients, especially within reference ART clinics. Such sampling strategy could be further strengthened for informed ART monitoring and HIVDR prevention perspectives.