(052) Adverse post-vaccination events reported with anti-COVID-19 vaccines in Burkina Faso: analysis of spontaneous reports

Publication Number: 389

Background: The rapid deployment of COVID-19 vaccines to a large part of the population requires an emphasis on their safety. However, the weakness of the pharmacovigilance system in countries with limited resources and more specifically in Burkina Faso constitutes a major challenge for the monitoring of adverse events following vaccination (AEFI).

Objectives: i) describe the characteristics AEFIs reported to the national pharmacovigilance center of Burkina Faso in connection with anti-COVID-19 vaccines and ii) assess the performance of the surveillance system for AEFIs linked to anti-COVID-19 vaccines in Burkina Faso according to the WHO criteria for a public health program.

Methods: We performed a retrospective analysis of AEFIs potentially linked to anti-COVID-19 vaccines reported in Burkina Faso from June 2021 to November 2022. We used the WHO criteria to assess the pharmacovigilance activities of the COVID-19 vaccination program. The assessment of the severity of AEFI was also carried out by considering the severity criteria defined by the WHO, Categorical variables were described using percentage and continuous variable with median and interquartile range. The Pearson chi square test was used to compare categorical variables. The incidence rate of AEFI was calculated for 100,000 doses of vaccines administered. The statistical significance level was 0.05.

Results: Overall, 983 CIRS related to all vaccines have been reported in VigiBase® on behalf of Burkina Faso, of which 973 concerned anti-COVID-19 vaccines and 32.6% of all 2,988 reports. The ratio MAPI/ individual cases of safety reports (CIRS) was 2.1.
In total, the median age of vaccinated people who showed at least one AEFI after vaccination was 42 (IQR: 32; 52) years.
Almost all AEFIs (90.1%) were systemic in nature. Headache (21.2%), fever (19.4%) and myalgia (11.0%) were the most frequently reported AEFIs. Regarding AEFI of local origin (10.0%), only pain at the injection site was reported.
Of a total of 973 CIRS, 18 cases (1.8%) were registered as serious AEFI. Of these, 9 AEFIs (50%) were prolonged hospitalizations, 4 AEFIs (22.2%) were life-threatening, 3 AEFIs (16.7%) concerned disability and 2 AEFIs (11.1 %) were related to unspecified events.

The overall notification rate of potentially vaccine-related AEFIs was 27.8 per 100,000 doses of vaccines administered. The median time for recording notifications in VigiBase® was 188 days (IQR: 149; 286). The median time between the appearance of AEFI and the transmission of the report to the CNVPS was 180 days (IQR: 136; 281).

Conclusions: The time taken to transmit and then register cases on VigiBase® was long and the overall AEFI notification rate was low. It is necessary to improve these delays in order to improve the performance of the system for the detection of signals.