Determinants of non‑prescribed antibiotic use in Sao Tomé and Principe – A household survey

Background

Non-prescribed antibiotic use is a major driver of antimicrobial resistance, which remains a global public health challenge. Understanding the determinants of this practice is crucial for the development of preventive strategies. This study aimed to assess the prevalence and determinants of non‑prescribed antibiotic use in the Água Grande district, São Tomé and Príncipe.

Methods

A household survey was conducted between May and July 2025 using a systematic geographic sampling approach. Data was collected through structured questionnaires administered to 175 adults identified as primary household decision‑makers (PHDMs) who reported antibiotic use within their household in the previous six months. The weighted prevalence of antibiotic misuse and the corresponding 95% confidence intervals (95%CI) were estimated. A multivariable logistic regression model was used to assess the determinants of antibiotic use without medical prescription. Odds ratios (ORs) and their respective 95%CIs were calculated.

Results

Prevalence of non-prescribed antibiotic use was 86.6% (95%CI:83.8–88.9). After adjustment, this practice was more likely to be reported by PHDMs who perceived antibiotics as being easily accessible in the country (OR = 5.0; 95%CI:2.51–9.81). In contrast, this practice was less likely to be reported by female PHDMs (OR = 0.56; 95%CI:0.32–0.99), those with higher monthly income (OR = 0.40;95%CI:0.20–0.79), and those demonstrating optimal knowledge about antimicrobial resistance (OR = 0.36; 95%CI:0.20–0.56).

Conclusions

Non-prescribed antibiotic use is highly prevalent in this setting. This practice is influenced not only by sociodemographic factors but also by the perceived ease of access to antibiotics and the level of knowledge about antimicrobial resistance. These findings highlight the need to strengthen regulatory policies governing antibiotic distribution, alongside the implementation of targeted educational interventions to promote rational antibiotic use.

Key messages

• The high prevalence of non‑prescribed antibiotic use represents significant public health concern, underscoring the need for the development and implementation of effective preventive strategies.

• Public health strategies should prioritize the strengthening of regulatory policies governing antibiotic dispensation and the implementation of educational programs to promote rational antibiotic use.