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 (anti/PF-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.

Side Effects of COVID-19 Pfizer-BioNTech mRNA Vaccine in Children Aged 12-18 Years in Saudi Arabia.

Background: Massive vaccination campaigns have been undertaken globally to combat the spread of the Coronavirus Disease 2019 (COVID-19). While most COVID-19 vaccines have shown excellent efficacy and safety profiles in clinical studies, real-world monitoring of vaccine safety is still important. In this study, we aimed to investigate the early side effects of Pfizer-BioNTech (BNT162b2) mRNA vaccine in children between 12-18 years old in Saudi Arabia. Method: To investigate the side effects in children in this age range following the administration of either one or two doses of Pfizer-BioNTech (BNT162b2) mRNA vaccine, we conducted a retrospective, cross-sectional study using a self-administered online survey. General and demographic data were collected, and vaccine-associated side effects following vaccination were evaluated. Results: The study recruited a total of 965 eligible participants. Overall, 571 (60%) of the study participants reported at least one side effect following Pfizer-BioNTech (BNT162b2) mRNA vaccination. The most frequently reported side effects were pain or redness at the site of injection (90%), fatigue (67%), fever (59%), headache (55%), nausea or vomiting (21%), and chest pain and shortness of breath (20%). Joint or bone pain were reported less frequently among our participants (2%). Our data showed that more female participants reported side effects compared to male participants, with 52% and 48%, respectively. Side effects were more common after the second dose compared to the first dose in our study cohort. Conclusions: While 60% of the children (12-18 years old) who received Pfizer-BioNTech (BNT162b2) mRNA vaccine reported side effects, our data showed that these side effects were not different from those that were reported in the clinical trials which lasted only for a few days. Side effects were more common after the second dose. Larger epidemiological and molecular studies are needed to evaluate the safety and the effectiveness of COVID-19 vaccine in protection of children against SARS-CoV-2 reinfections.