Long-term effects of Pfizer-BioNTech COVID-19 vaccinations on platelets

Abstract

There is a global concern about the safety of COVID-19 vaccines associated with platelet function. However, their long-term effects on overall platelet activity remain poorly understood. Here we address this problem by image-based single-cell profiling and temporal monitoring of circulating platelet aggregates in the blood of healthy human subjects, before and after they received multiple Pfizer-BioNTech (BNT162b2) vaccine doses over a time span of nearly 1 year. Results show no significant or persisting platelet aggregation trends following the vaccine doses, indicating that any effects of vaccinations on platelet turnover, platelet activation, platelet aggregation, and platelet-leukocyte interaction was insignificant.

Keywords: COVID-19; mRNA vaccine; platelet aggregation; thrombosis.

FIGURE 1

Monitoring of platelet activity in the blood of healthy subjects before and after Pfizer‐BioNTech vaccine doses. (A) Experimental procedure. (B) Concentration of circulating platelet aggregates in a female subject. Insets show the size distribution and typical images of single platelets and platelet aggregates. Scale bars, 30 μm [Color figure can be viewed at wileyonlinelibrary.com]

FIGURE 2

Statistical results. (A) Monitored concentrations of circulating platelet aggregates in healthy subjects. (B) Monitored concentrations of circulating platelet‐leukocyte aggregates in healthy subjects. (C) Laboratory test results. (D) Concentrations of circulating platelet aggregates in healthy subjects (for five vaccination periods), compared with those in COVID‐19 patients. (E) Concentrations of circulating platelet‐leukocyte aggregates in healthy subjects in comparison with those in COVID‐19 patients. Ns: P > 0.05; *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001; ****P ≤ 0.0001 [Color figure can be viewed at wileyonlinelibrary.com]