Abstract
INTRODUCTION: Vitamin D and zinc sufficiency are theoretically acclaimed to influence immune-boosting potentials following various immunizations. Herein, we explored the impact of these micronutrients on immune responses following Oxford-AstraZeneca coronavirus disease 2019 (COVID-19) vaccination among Nigerians. METHODS: Two hundred healthcare workers (HCs) who presented at the Rivers State University Teaching Hospital were recruited during the first dose and followed up 4 weeks post-first and post-second doses. Data (serum vitamin D/zinc, COVID-19 anti-spike immunoglobulin G [ASIgG]) were determined on the day of the first dose and repeated 4 weeks post-first dose and 4 weeks post-second dose. Vitamin D (VitD) status, assessed using serum 25(OH)D, was categorized as sufficient (≥50 nmol/L) or insufficient/deficient (<50 nmol/L) while zinc status was categorized as sufficient (≥11.3 µmol/L) or insufficient (<11.3 µmol/L). Post-second dose ASIgG titer status was categorized as optimal (>7,352 AU/mL) or sub-optimal (<7,352 AU/mL) as defined by the World Health Organization. Statistical significance was defined as p<0.05. RESULTS: HCs with both VitD and zinc sufficiency (n=97) had higher ASIgG titer levels (4 weeks post-first dose=15,977±367.88 AU/mL; 4 weeks post-second dose=22,603±451.18 AU/mL) after the first and second doses compared to only the VitD sufficient (n=58) cohorts (4 weeks post-first dose=4,680±154.77 AU/mL; 4 weeks post-second dose=7,850±200.60 AU/mL) and the zinc-sufficient (n=63) cohorts (4 weeks post-first dose=5,770±160.41 AU/mL; 4 weeks post-second dose=8,100±206.91 AU/mL) (p<0.05). The VitD and zinc-sufficient HCs were also more likely to achieve optimal ASIgG titer levels (odds ratio, 2.97; 95% confidence interval, 2.11-4.123; p<0.001) 4 weeks post-second dose following adjustment for confounders. CONCLUSION: VitD and zinc sufficiency had a positive impact on immune responses following AstraZeneca COVID-19 vaccination.