Cohort event monitoring for safety signal detection in adult individuals 18 years and above after immunisation with coronavirus disease 2019 vaccines in Nigeria.

Introduction: In Nigeria, immunisation with coronavirus disease 2019 (COVID-19) vaccines commenced in March 2021. COVISHIELD from AstraZeneca (AZ), a viral vector vaccine, was the brand administered in the first phase of vaccinations for pre-determined eligible adults 18 years and above. As more brands of COVID-19 vaccines have been introduced in Nigeria, identifying effective and safe vaccine brands is essential to pharmacovigilance and public health. The current study assessed the safety of the AZ-AZD1222 (ChAdOx1) COVID-19 vaccine in adults during the first phase of the vaccination exercise in Nigeria. Methodology: We conducted a descriptive analysis of safety data from selected vaccination sites across six states in Nigeria between June 2021 and September 2021. Respondents were monitored over 3 months for local and systemic reactions, as well as hospitalisation and mortality. Measures obtained from respondents include age, sex, pre-existing comorbidity, local and systemic reactions to vaccines, timing onset of reactions, hospitalisation and mortality. Bivariate and multivariable regression models were used to assess factors associated with vaccine reactogenicity. Results: A total of 1284 individuals were enrolled in the cohort study from the six selected states (Anambra, Borno, Edo, Katsina, Lagos and Plateau) representing the geopolitical zones of Nigeria. A total of 675 individuals or 52.6% of enrolees reported non-serious adverse effects, and only one individual or 0.08% reported a serious adverse event following immunisation in the first 7 days after vaccination. None of the enrolled participants reported adverse events requiring hospitalisation. The most common self-reported symptoms amongst vaccine recipients were tenderness at the injection site 20.9% and fever 20.3%. A majority of symptoms (55.5%) occurred on or before the 3rd day after vaccination. Multivariable logistic regression model showed that age 60 years or above (vs. 18-24 years) was significantly associated with a lower likelihood of a vaccine-related symptomatic reaction (adjusted odds ratio: 0.35; 95% confidence interval: 0.20-0.61). There was no reported mortality amongst all the enrolled and followed-up vaccine recipients. Conclusion: Our findings suggest that the safety profile of the AZ vaccine is acceptable, and the observed symptoms were mild and mostly within the first 3 days following vaccination. Vaccine recipients will benefit from counselling about potential transient reactions, and improving public awareness can potentially encourage the uptake of vaccines and reduce the spread of the COVID-19 pandemic.

Patterns of adverse drug reaction signals in NAFDAC pharmacovigilance activities from January to June 2015: safety of drug use in Nigeria.

Adverse drug reactions (ADRs) are expected to be associated with an economic drain on the healthcare systems. The study was carried out to determine the occurrence of ADRs reported to NAFDAC Pharmacovigilance from January to June 2015, to illustrate the pattern of organ system affected by ADRs, to assess the completeness of ADR report, to determine the relationship between the occurrence of ADRs with suspect drugs and the use of concomitant drugs as well as to generate possible signals from the reported ADRs. A total number of 921 ADR cases reported from January to June 2015 were analyzed using SPSS version 22. A higher percentage of ADR reports were seen in females (65.5%). The highest percentages of reports (45.6%) were from the age range of 21-40 years, most of the suspected drugs reported had both NAFDAC (50.2%) and batch number identification (65.6%). HIV (56.9%) was the most prevalent indication reported for using the suspected drug; Zidovudine/Lamivudine/Nevirapine combination (16.9%) was reported as the suspected drug with the highest occurrences of ADRs and generalized body itching (6.9%) as the most prevalent ADR. "General disorders" (47.3%) was the most predominant organ system affected by ADRs and Pharmacists were revealed as the highest reporters of ADRs (80.2%). Overall, patients on ARVs should be vigilantly followed up as they are mostly prone to ADRs. Adverse drug reaction reporting systems need to be robust and complete in order to be able to detect new drug alerts, possible signals and improve pharmacovigilance.