Impact of SARS-CoV-2 AstraZeneca vaccine on safety and blood elements of Egyptian healthcare workers

Background: Many coronavirus disease 2019 (COVID-19) vaccines were approved worldwide. Their safety was the primary concern. In Egypt, Oxford–AstraZeneca (AZ) vaccine was the first approved vaccine initially for healthcare workers (HCWs). Objective: We aim to determine adverse events and hematological abnormalities following the COVID-19 AZ vaccine and estimate the infection rate of the candidates by COVID-19 between the first and second doses of vaccination. Methods: Within 8–10 days of receiving their initial dose of the AZ vaccine, 909 HCWs were assessed for adverse events as part of a prospective longitudinal study. Complete blood counts (CBCs) were evaluated before and one month after vaccination. Results: 37.2% of the candidates experienced side effects following vaccination. Pain at the injection site was the most common (25.4%) and more frequent in participants between 20 and 40 years (27.9%). The mean total leukocyte count (TLC), absolute leukocyte count (ALC), absolute neutrophil count (ANC), and absolute monocyte count (AMC) increased one month following vaccination (P < 0. 001). Sixty-six vaccinated HCWs were infected with COVID-19 between the two vaccine doses. 82% were infected after 14 days of the first dose, while 18% were infected before 14 days (P < 0.0001). Conclusions: Most of the vaccinated personnel did not experience any side effects after the first dose of the vaccine. Furthermore, the most common complaints were pain at the injection site, fatigue, fever, headache, arthralgia, myalgia, and chills. Infected people with COVID-19 after the first dose had significantly more severe disease if they were infected before 14 days than those who got infected later on.