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. MethodsIn 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.

Aim:We performed a prospective, analytical study from 01 January to 31 March 2009 in the Ophthalmology Unit of the Gyneco-Obstetric and Pediatric Hospital of Yaounde, aiming to determine the profile of central corneal thickness (CCT) in the Cameroonian nonglaucomatous black population and its relationship with intraocular pressure (IOP).Results and discussion:Four hundred and eighty-five patients (970 eyes) meeting our inclusion criteria were selected for this study. The average CCT was 529.29 ± 35.9 μm in the right eye (95% confidence interval [CI]: 526.09–532.49), 528.19 ± 35.9 μm in the left eye (95% CI: 524.99–531.40) and 528.74 ± 35.89 μm in both eyes (95% CI: 526.48–531.00), range 440 to 670 μm. The average IOP was 13.01 ± 2.97 mmHg in both eyes (95% CI: 12.82–13.19). A rise in CCT by 100 μm was followed by an increase in IOP of about 2.8 mmHg (95% CI: 2.3–3.6) for both eyes taken together. Linear regression analysis showed that corneal thickness was negatively correlated with age and IOP was positively related with age.Conclusion:CCT in the Cameroonian nonglaucomatous black population was found to be lower compared with CCT values in Caucasian and Asian populations. On the basis of reference values ranging between 527 and 560 μm, an adjustment of IOP values by a correction factor is required for many Cameroonian patients. This will improve the diagnosis and follow-up of glaucoma by helping to detect true ocular hypertension.

Official case counts suggest Africa has not seen the expected burden of COVID-19 as predicted by international health agencies, and the proportion of asymptomatic patients, disease severity, and mortality burden differ significantly in Africa from what has been observed elsewhere. Testing for SARS-CoV-2 was extremely limited early in the pandemic and likely led to under-reporting of cases leaving important gaps in our understanding of transmission and disease characteristics in the African context. SARS-CoV-2 antibody prevalence and serologic response data could help quantify the burden of COVID-19 disease in Africa to address this knowledge gap and guide future outbreak response, adapted to the local context. However, such data are widely lacking in Africa. We conducted a cross-sectional seroprevalence survey among 1,192 individuals seeking COVID-19 screening and testing in central Cameroon using the Innovita antibody-based rapid diagnostic. Overall immunoglobulin prevalence was 32%, IgM prevalence was 20%, and IgG prevalence was 24%. IgM positivity gradually increased, peaking around symptom day 20. IgG positivity was similar, gradually increasing over the first 10 days of symptoms, then increasing rapidly to 30 days and beyond. These findings highlight the importance of diagnostic testing and asymptomatic SARS-CoV-2 transmission in Cameroon, which likely resulted in artificially low case counts. Rapid antibody tests are a useful diagnostic modality for seroprevalence surveys and infection diagnosis starting 5-7 days after symptom onset. These results represent the first step towards better understanding the SARS-CoV-2 immunological response in African populations.

BackgroundThe problem of access to medical information, particularly in low-income countries, has been under discussion for many years. Although a number of developments have occurred in the last decade (e.g., the open access (OA) movement and the website Sci-Hub), everyone agrees that these difficulties still persist very widely, mainly due to the fact that paywalls still limit access to approximately 75% of scholarly documents. In this study, we compare the accessibility of recent full text articles in the field of ophthalmology in 27 established institutions located worldwide.MethodsA total of 200 references from articles were retrieved using the PubMed database. Each article was individually checked for OA. Full texts of non-OA (i.e., “paywalled articles”) were examined to determine whether they were available using institutional and Hinari access in each institution studied, using “alternative ways” (i.e., PubMed Central, ResearchGate, Google Scholar, and Online Reprint Request), and using the website Sci-Hub.ResultsThe number of full texts of “paywalled articles” available using institutional and Hinari access showed strong heterogeneity, scattered between 0% full texts to 94.8% (mean = 46.8%; SD = 31.5; median = 51.3%). We found that complementary use of “alternative ways” and Sci-Hub leads to 95.5% of full text “paywalled articles,” and also divides by 14 the average extra costs needed to obtain all full texts on publishers’ websites using pay-per-view.ConclusionsThe scant number of available full text “paywalled articles” in most institutions studied encourages researchers in the field of ophthalmology to use Sci-Hub to search for scientific information. The scientific community and decision-makers must unite and strengthen their efforts to find solutions to improve access to scientific literature worldwide and avoid an implosion of the scientific publishing model. This study is not an endorsement for using Sci-Hub. The authors, their institutions, and publishers accept no responsibility on behalf of readers.

Background A year after the COVID-19 pandemic started, there are still few scientific reports on COVID-19 in Africa. This study explores the clinical profiles and factors associated with COVID-19 in Cameroon. Materials and methods In this prospective cohort study, we followed patients admitted for suspicion of COVID-19 at Djoungolo Hospital between 01st April and 31st July 2020. Patients were categorised by age groups and disease severity: mild (symptomatic without clinical signs of pneumonia), moderate (with clinical signs of pneumonia without respiratory distress) and severe cases (clinical signs of pneumonia and respiratory distress not requiring invasive ventilation). Demographic information and clinical features were summarised. Multivariable analysis was performed to predict risk. Findings A total of 313 patients were admitted during the study period; 259 were confirmed cases of COVID-19 by Polymerase Chain Reaction (PCR). Among the confirmed cases, the male group aged 40 to 49 years (13.9%) was predominant. Disease severity ranged from mild (26.2%; n = 68) to moderate (59%; n = 153) to severe (14.7%; n = 38); the case fatality rate was 1% (n = 4). Dysgusia (46%; n = 119) and hyposmia/anosmia (37.8%; n = 98) were common features of COVID-19. Nearly one-third of patients had comorbidities (29%; n = 53), of which hypertension was the most common (18.9%; n = 49). Participation in mass gatherings (Odds Ratio (OR) = 2.37; P = 0.03) and dysgusia (OR = 2.09, P = 0.02) were predictive of diagnosis of COVID-19. Age groups 60 to 69 (OR = 7.41; P = 0.0001), 50 to 59 (OR = 4.09; P = 0.03), 40 to 49 (OR = 4.54; P = 0.01), male gender (OR = 2.53; P = 0.04), diabetes (OR = 4.05; P = 0.01), HIV infection (OR = 5.57; P = 0.03), lung disease (OR = 6.29; P = 0.01), dyspnoea (OR = 3.70; P = 0.008) and fatigue (OR = 3.35; P = 0.02) significantly predicted COVID-19 severity. Conclusions Most COVID-19 cases in this study were benign with low fatality. Age (40–70), male gender, HIV infection, lung disease, dyspnoea and fatigue are associated with severe COVID-19. Such findings may guide public health decision-making.