How well are ethical principles applied in the field? Independent monitoring of consent and confidentiality in the 2024–2025 Cameroon Population-based HIV Impact Assessment (CAMPHIA)

Background Population-based HIV Impact Assessment (PHIA) surveys generate the national estimate on which HIV programmes are steered. As with all research involving human participants, these surveys have to be implemented following international and national ethical guidelines, including respect for informed consent and confidentiality, as specified in the protocol approved by the competent ethics committee. We conducted an independent ethical compliance monitoring of the CAMPHIA 2024–2025 survey in Cameroon. Methods Cross-sectional independent monitoring was nested within CAMPHIA, conducted from 5 September to 10 October 2024 in enumeration areas already surveyed across six settings (Adamawa, Littoral, West, South-West, Douala and Yaoundé). Residents aged 15 years and over were interviewed after their CAMPHIA visit by monitors who were independent of the survey teams. Three Ethical Compliance Indices (ECI, 0–100) were constructed as formative composites: information (nine mandatory items), consent and procedures (age-conditional items, with assent and parental authorisation required below 21 years) and confidentiality. Proportions carry Wilson 95% confidence intervals, while index means both normal approximation and bootstrap intervals. Results Of 258 respondents monitored (median age 40 years, IQR 28–50; 53.1% women; 7.8% under 21), 236 (91.5%) had taken part in CAMPHIA. The level of participant protection was dependent on the domain under study: information at 87.7 (95% CI: 85.7–89.7), consent and procedure at 93 (95%CI: 91.2–94.8) and confidentiality at 98.3 (95% CI 96.9–99.7). In terms of information, 38 percentage points were covered: almost everything was confidential (100.0%), the blood draw (99.6%) and voluntary participation (98.6%) were near-universal but contact details (69.9%) and compensation arrangements (62.0%) were not. The level of administrative visibility was 35.6%, authorisation was not displayed for 30.1% of cases and ethical clearance was presented in the remaining 30.1%. Two thirds (66.3%) had seen no visual material. Information and consent differed significantly between regions (p < 0.001 and p = 0.005), confidentiality did not (p = 0.311), and the regional orderings of the two were discordant. Conclusion Independent ethical compliance monitoring should be integrated into population-based HIV surveys as a quality-assurance mechanism. Strengthening standardised information delivery, visible administrative and ethical documentation, and regionally consistent procedures could improve participant protection and reinforce public trust in national HIV surveillance, ultimately supporting more credible programme planning.