Evaluation of hematological parameters and thrombocytopenia following Pfizer-BioNTech (BNT162b2) SARS-CoV-2 vaccination

Objectives: To evaluate hematological parameters and thrombotic profiles of healthy individuals who received Pfizer-BioNTech (BNT162b2) vaccines in Saudi Arabia. Methods: Hematological parameters and the incidence of anti platelet factor-4 (antilPF-4) antibodies were evaluated in 40 participants who were eligible for COVID-19 vaccination in Saudi Arabia (above 18 years old) at Jazan University Hospital. These parameters were assessed at 2 different timepoints; at day 0 (the day of receiving the first dose of Pfizer-BioNTech (BNT162b2) and prior to vaccination) and 14-21 days after receiving the vaccine. Results: Among the participants, 38 (80%) were men, while 12 (20%) were women, with a mean age of 27 years. A total of 15% of the participants reported previous infection with SARS-CoV-2 and 3 patients had a history of diabetes mellitus and hypertension. Hematological parameters results in those vaccines showed no significant changes between the 2 timepoints, such as, day 0 (just before receiving vaccination) and 14 to 21 days post vaccination. Further, anti/PF4 antibodies were negative for all participants following vaccination. Conclusion: Our data showed that the incidence of hematological abnormalities or induction of anti/PF4 antibodies following Pfizer-BioNTech (BNT162b2) vaccination is not common, which is consistent with several previous reports. However, larger studies with more participants evaluated at different timepoints following vaccination are warranted to exclude potential transient hematological abnormalities.