Prevalence of Adverse Events Post-COVID-19 Vaccination amongst the Adult Zambian Population

Introduction: COVID-19 continues to be a public health concern despite several practical interventions to curb its spread. Now, widespread vaccination appears to be the most important strategy in winning the fight against this deadly pandemic by promoting herd immunity. However, a lack of independent and local studies on vaccines’ safety may adversely impact the vaccine uptake and eventually the overarching goal of reducing disease transmission.

Objective: To determine the prevalence of adverse events post COVID-19 vaccination amongst the adult Zambia population.

Methods: This was a descriptive cross-sectional study conducted among recipients of COVID-19 vaccines in Zambia. The study was conducted between July and August 2021. 584 adult individuals who had access to the questionnaire were enrolled. Relationships between patients' demographics and Adverse Events (AEs) were assessed using the chi-square (χ2) test given the categorical nature of the data.

Results: Pain at the injection site (79.8%), headache (57.4%), fatigue (55.5%), chills (52.6%), fever (42.3%), and joint pains (37.5%) were the most commonly reported adverse events. When stratified by gender, pain at the injection site (p = 0.01), limitation of arm movement (p < 0.001), chills (p = 0.017), headache (p = 0.044), fatigue (p = 0.004), nausea or vomiting (p < 0.001) were statistically significant, with females mostly affected. There was a statistically significant difference in the case of limitation of arm movement (20.7% vs. 9.9%, p = 0.031), chills (54.8% vs. 36.6%, p = 0.004), headache (59.6% vs. 40.8%, p = 0.003) and fatigue (57.5% vs. 40.8%, p = 0.008) between those 49 years and below compared to those above 50 years.

Conclusion: Our study provides evidence of adverse events being experienced by the recipient of COVID-19 vaccines and that these have been mainly mild. Healthcare authorities need to educate the public about the possible adverse events associated with COVID-19 vaccines and how to report these events should they experience some. This will improve pharmacovigilance of adverse events associated with COVID-19 vaccines.