The Impact of the COVID-19 Pandemic on Spontaneous Reporting of Adverse Drug Reactions in the Central Region of Portugal: An International Journal of Medical Toxicology and Drug Experience

ABSTRACT

Introduction: The COVID-19 pandemic has had an impact on several sectors of the society. Whether it has disrupted drug safety monitoring is yet to be determined. Objective: To investigate whether the COVID-19 pandemic has had an impact on the proportions of spontaneous reports (SRs) of serious and unexpected adverse drug reactions (ADRs). Methods: SRs received by the Coimbra Pharmacovigilance Unit (UFC) between January 2017 and December 2021 were included, except for those containing COVID-19 vaccines as suspected medicines. The SRs were categorized into two groups pre-pandemic (2017-2019);and post-pandemic (2020-2021). The SRs were classified as serious or non-serious, and expected or unexpected, depending on the seriousness and expectedness of the suspected ADRs, according to the WHO criteria and the Summary of Product Characteristics [SmPC] of each suspected medicine, respectively [1,2]. To study the impact of the COVID-19 pandemic on the patterns of spontaneous reporting of suspected ADRs, two null hypotheses were proposed to test whether (i) the seriousness, and (ii) the expectedness were independent of the pandemic (i.e., if the pandemic has had no impact, then the proportions of SRs containing (i) serious and (ii) unexpected ADRs were expected to be the same in both periods). The qui-square test was used to test the hypotheses;p-values < 0.001 were considered statistically significant. Microsoft Excel® was used for the statistical analyses. Results: A total of 1,311 and 657 SRs were received in the prepandemic and post-pandemic periods, respectively. Of the 1,311 SRs received in the three pre-pandemic years, 1,012 (77%) were serious and 657 (13%) contained unexpected ADRs;of the 657 SR received during the two post-pandemic years, 434 (66%) were serious and 133 (20%) contained unexpected ADRs. The changes from pre- to postpandemic on both proportions of SRs containing serious (an absolute decrease of 11%;p = 0.01) or unexpected ADRs (an absolute increase of 7%;p = 0.01) were not statistically significant. Conclusion: The COVID-19 pandemic has had not a significant impact on the proportions of SRs of serious or unexpected ADRs in the Central Region of Portugal. Further research should be carried out in other pharmacovigilance databases to understand if the present conclusions are applicable to other geographic regions.