Tropical Haematological Responses to AstraZeneca COVID-19 Vaccination: A Comparative Case-Control Study in Nigeria

Abstract

The COVID-19 pandemic has underscored the imperative of effective vaccination strategies, and the AstraZeneca COVID-19 vaccine has been extensively deployed globally, including in Nigeria. However, the haematological effects of this vaccine in the Nigerian population remain poorly understood. This study aimed to bridge this knowledge gap by investigating the haematological changes associated with the AstraZeneca COVID-19 vaccination in a Nigerian population. Employing a case-control design, 102 participants (51 vaccinated and 51 unvaccinated) were recruited and analyzed, with sample size determined using G*Power software to ensure adequate power for detection of significant differences. Blood samples were collected and analyzed using a five-part differential Full Blood Count (FBC) on an autohaematologic analyzer. The results revealed significant changes in haematological parameters, including increased Packed Cell Volume (PCV) (42.25±0.76% vs 38.78±0.66%, p=0.0008), elevated White Blood Cell (WBC) (7.21±0.36 vs 4.37±0.09 x 10^9/L, p<0.001), decreased platelet count (217.78±7.69 x 10^9/L vs 242.14±5.88 x 10^9/L, p=0.001), and elevated Platelet Distribution Width (PDW) (15.21±0.34 FL vs 13.75±0.13 FL, p=0.0001). These findings have important implications for public health policy and practice, particularly in the context of COVID-19 vaccination strategies, highlighting the need for personalized approaches to vaccine development and administration.