# Trends and Patterns of Adverse Drug Reaction Reporting in Sierra Leone: A Retrospective Analysis of VigiFlow Data (2008–2022)

## TL;DR

This study analyzed adverse drug reaction reports in Sierra Leone from 2008 to 2022, finding trends in reporting, common medications involved, and the need for better data quality.

## Contribution

The study provides the first long-term analysis of ADR reporting in Sierra Leone using VigiFlow data, highlighting patterns and challenges in pharmacovigilance.

## Key findings

- ADR reporting increased after 2015, peaking in 2021, but dropped significantly in 2020, likely due to the impact of the COVID-19 pandemic.
- Pharmacists submitted the most reports and achieved the highest completeness scores, emphasizing their role in pharmacovigilance.
- Anti-infective and antiparasitic drugs, including ivermectin and albendazole, were most frequently associated with ADRs, reflecting large-scale public health campaigns.

## Abstract

Adverse drug reactions (ADRs) present significant obstacles for healthcare systems, impacting both patient safety and the effectiveness of treatments. Despite this, there is a scarcity of research on ADR reports in Sierra Leone, especially over long periods. This study aims to investigate the characteristics and reporting patterns found in the Sierra Leone pharmacovigilance database managed through VigiFlow.

This study analyzes reports of ADRs from Sierra Leone's national pharmacovigilance database, VigiFlow, spanning from January 2008 to December 2022. Data collected included patient demographics (age, sex), reporter characteristics (type of reporter, year of reporting), and ADR‐specific information (suspected medication, indication, ADR types (MedDRA), seriousness, outcome, actions taken, and time to onset), and completeness score. Descriptive statistics, chi‐square tests, and the Kruskal‐Wallis test with Bonferroni‐adjusted post hoc tests were applied to identify patterns and associations within the dataset.

A total of 3381 individual case safety reports (ICSRs) were analysed. The majority of reports involved females (54.7%) and adults aged 18 to 44 years (51.4%). Reporting rates increased after 2015, peaking in 2021. The most frequently implicated medications were anti‐infective drugs (40.7%) and antiparasitic medicines (34.1%), particularly ivermectin, albendazole, and vaccines for cholera and yellow fever. The most commonly reported ADRs were headache (13.2%), fever (12.2%), and diarrhoea (7.6%), primarily affecting the nervous system and general disorder classes. Pharmacists were responsible for 39.0% of reports and achieved the highest completeness score, with a mean of 0.78. Age was significantly associated with the seriousness, outcome, and onset time of ADRs (p < 0.001), while gender was significantly associated with onset time (p = 0.007).

ADR reporting in Sierra Leone has improved, with antiparasitic medicines and vaccines most frequently linked to reactions. Sustaining progress requires enhanced training, public engagement, and strengthened active pharmacovigilance to ensure completeness and patient safety.

Most ADR reports involved adults aged 18–44 years and females, indicating higher reporting among women and young adults.Pharmacists and other healthcare professionals accounted for the majority of reports, reaffirming their central role in pharmacovigilance and the importance of strengthening reporting culture across all cadres.Anti‐infective and antiparasitic medicines, particularly ivermectin, albendazole, and vaccines (cholera, yellow fever), were most frequently suspected, reflecting the influence of large‐scale treatment and immunisation campaigns on national reporting trends.ADR reporting fluctuated substantially across the years, peaking in 2021 and reaching the lowest level in 2020, suggesting that public health emergencies such as COVID‐19 may disrupt routine pharmacovigilance activities.The completeness of reports was suboptimal, with missing data on dosage, indication, and seriousness criteria, underscoring the need for improved data quality assurance and feedback mechanisms.The most commonly reported ADRs were headache, pyrexia, diarrhoea, and pruritus, primarily non‐serious and self‐limiting, highlighting that most reported reactions were mild but remain critical for medicine safety monitoring.

Most ADR reports involved adults aged 18–44 years and females, indicating higher reporting among women and young adults.

Pharmacists and other healthcare professionals accounted for the majority of reports, reaffirming their central role in pharmacovigilance and the importance of strengthening reporting culture across all cadres.

Anti‐infective and antiparasitic medicines, particularly ivermectin, albendazole, and vaccines (cholera, yellow fever), were most frequently suspected, reflecting the influence of large‐scale treatment and immunisation campaigns on national reporting trends.

ADR reporting fluctuated substantially across the years, peaking in 2021 and reaching the lowest level in 2020, suggesting that public health emergencies such as COVID‐19 may disrupt routine pharmacovigilance activities.

The completeness of reports was suboptimal, with missing data on dosage, indication, and seriousness criteria, underscoring the need for improved data quality assurance and feedback mechanisms.

The most commonly reported ADRs were headache, pyrexia, diarrhoea, and pruritus, primarily non‐serious and self‐limiting, highlighting that most reported reactions were mild but remain critical for medicine safety monitoring.