Differences in complete blood count parameters in patients with COVID-19 diagnosis based on vaccination status (literature review)

Abstract

Relevance. Due to the large-scale vaccination campaigns against the SARS-CoV-2 coronavirus taking place worldwide, the question arises as to how vaccination may affect complete blood count (CBC) parameters in COVID-19 cases. Research objective: assess differences in complete blood count parameters in COVID-19 patients based on their vaccination status. Materials and methods. A review of publications was conducted describing and presenting the complete blood count parameters in patients with verified COVID-19, by stratifying them into vaccinated and unvaccinated individuals against the SARS-CoV-2 virus-caused disease. Subsequently, a meta-analysis of the results for each CBC parameter was carried out by describing identified differences among patients with mild and moderate COVID-19, lacking comorbidities affecting CBC indicators. Results. The analysis conducted allowed to determine that the complete blood count parameters do not exceed the reference range in most cases in both groups, excepting those of individuals with a severe disease course. The exception is the erythrocyte sedimentation rate (ESR) (42 [20.5–63.5] (∑n = 107, Me [Q1–Q3])) mm/h in unvaccinated individuals. Also, a slightly lower absolute lymphocyte count is observed in vaccinated individuals (0.95 [0.58–1.62] × 109/L (∑n = 441, Me [Q1–Q3])). There is a twofold greater range of leukocyte quartile values in vaccinated individuals compared to unvaccinated individuals: 7.07 [4.07–12.31] × 109/L (∑n = 555, Me [Q1–Q3]) vs 5.68 [4.02–8.34] × 109/L (∑n = 2202, Me [Q1–Q3]). A similar pattern is observed for monocytes. Conclusion. Conducting a meta-analysis of laboratory parameters in COVID-19 cases among vaccinated and unvaccinated individuals allows for determining the effectiveness of vaccination as well as identify the major trends in dynamic changes for essential blood parameters among unvaccinated and vaccinated individuals in general or with certain immunobiological preparations.