This study highlights the importance of verifying HIV testing algorithms to reduce the risk of misdiagnoses caused by common false reactivity. Between 2020 and 2023, WHO supported 14 countries to assess rates of false reactivity and shared false reactivity across HIV rapid diagnostic tests (RDTs) used in HIV testing services. The study involved 26,278 results from 22 different RDT products, with sample sizes ranging from 100 to 302 results per country. The number of RDT products assessed varied between 4 and 13 per country. False reactivity rates ranged from 0 % to 3.32 %, with one country reporting a high false reactivity rate of over 4 % for one RDT. Five countries have no shared false reactivity between RDTs, while the remaining eight countries shared false reactivity across one to six pairs of RDT products. These findings were used to inform national policy, with more than 90 % of countries introducing new RDT products into their HIV testing algorithm based on these results. The study concludes that rates of false reactivity and shared false reactivity between RDT products vary across
countries. Therefore, conducting verification studies is crucial for updating national HIV testing algorithms and ensuring accurate diagnosis while also facilitating the market entry of new HIV testing products.

Background: In a context of HIV seropositivity below 5%, transitioning from a two-to a three-test algorithm is required to
secure positive predictive values > 99% for mitigating false reactivity. With Cameroon having 2.7% seroprevalence, we sought to ascertain events of false reactivity from eight WHO-prequalified HIV rapid diagnostic tests (RDTs) and design suitable combinations for the country three-test algorithm.
Methods: A facility-based study was conducted in July–August 2021 among 172 consenting clients attending health facilities in Yaoundé-Cameroon. Whole blood was collected and samples characterized in parallel using KHB Diagnostic Kit for HIV (1 + 2) Antibody and INNO-LIA HIV I/II Ag/Ab to rule out reactive cases. Two lots of each selected RDT were tested simultaneously in quadruplicate on HIV non-reactive samples and repeated by a different tester. RDTs were considered false positive if any reactivity was detected.
Results: Following characterization, 25 samples were HIV-reactive (i.e., ruled out) and 147 non-reactive.
Following random selection, 100 non-reactive samples tested for false reactivity revealed: 0% (0/100) First Response HIV 1–2-O Card, 0% (0/100) First Response HIV1 + 2/Syphilis Combo, 0% (0/100) STANDARD Q HIV/Syphilis Combo, 0% (0/99) ONE STEP Anti-HIV1& 2 (one invalid result); 1% (1/100) Determine HIV Early Detect and Bioline HIV/Syphilis Duo, 2% (2/100) Alere Determine HIV-1/2, 4% (4/100) Rapid Test for Antibody to HIV.
Conclusion: In the Cameroonian context, HIV false reactivity ranged from 0% to 4% across selected RDTs. Thus, a reliable
three-test algorithm ranks First Response HIV 1–2-0 Card, First Response HIV1 + 2/Syphilis Combo or STANDARD Q as suitable RDT-1 to mitigate false-positive events at the country-level.

Introduction : with the aim of guiding the strategic response to major viral infections, this study aimed to determine the epidemiological profile of HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) in the Far North region of Cameroon. Methods : we conducted a cross-sectional epidemiological surveillance study in the Mayo-Tsanaga Division and surrounding localities in the Far North region of Cameroon from August 1 to September 20, 2024. After obtaining informed consent, each participant was given a standard questionnaire and tested for the three infections (HIV, HBV, and HCV) in accordance with the national testing algorithm. The collected data were analyzed using Excel 2019 and Power BI software, with a statistical significance threshold set at p < 0.05. Results: a total of 3,188 participants were tested (60% female, median age 34 years [IQR 20-46]), of whom 396 tested positive overall, including 13 who were HIV-positive, 373 who were HBV-positive, and 10 who were HCVpositive. According to each type of infection, HIV, HBV and HCV seropositivity rates were 0.41% (13/3,170), 11.7% (373/3,188) and 0.31% (10/3,188), respectively. Despite the high endemicity of HBV (>8%), no statistically significant differences were observed by age or sex (p > 0.05).
Conclusion : the low prevalence rates (<1%) of HIV and HCV suggest that their elimination is effectively underway among populations in the Far North region of Cameroon. However, the high endemicity of HBV indicates ongoing transmission and
underscores the urgent need to prioritize vaccination as the primary preventive intervention toward elimination.

Updates on the Clinical Epidemiology of HIV-1 Group O Strains in Cameroon and Potential Implications on Diagnosis and Treatment Strategies.