Pfizer vaccine — what side effects came to light over time?

Aim of the study: COVID-19 vaccines were initially authorized based on short-term data from Phase 3 clinical trials in a highly selected population. This study assessed the long-term safety of the Pfizer-BioNTech COVID-19 vaccine BNT162b2 and variation in adverse event rates across clinically important subgroups.

Results: Of the 9518 participants (median age 36.6 years) in the primary safety population (vaccinated with BNT162b2 within 10 days of enrollment), most were female (69.0%), White (66.1%), and non-Hispanic (75.2%). The most frequent baseline health conditions were obesity/overweight (24.4%), hypertension (11.9%), and asthma (11.6%). The overall AESI rate was 13.65 per 1000 person-years. Most AESIs did not result in hospitalization (67.4%). The most common AESIs per 1000 person-years were arthritis/arthralgia (3.32), non-anaphylactic allergic reactions (2.84), and spontaneous abortion/stillbirth (3.10). The rate of all other AESIs was <1.0 per 1000 person-years. Unadjusted AESI rates (IRR; 95% CI) were higher in risk intervals than control intervals (2.32; 1.54-3.51) but were attenuated following adjustment for age (0.95; 0.53-1.72).

Aim of the study: During the COVID-19 pandemic, vaccinations were highly beneficial to public health, preventing disease and reducing mortality. This study aimed to investigate long-term adverse clinical symptoms following COVID-19 vaccination with the Oxford AstraZeneca (ChAdOx1 nCoV-19, Oxford), Pfizer-BioNTech (BNT162b2), and Moderna (mRNA-1273) vaccines.

Results: Menstrual irregularity was slightly higher among females who received Pfizer-BioNTech (14.8%) than among Oxford AstraZeneca recipients (18.9%). The highest proportion of recipients who were infected after vaccination was among those who received the Oxford AstraZeneca vaccine (46.3%). In conclusion, the most commonly reported long-term adverse effects after COVID-19 vaccination were chronic fatigue, cognitive impairment, and menstrual irregularity. Further large-scale studies are required to provide more conclusive evidence.

Aim of the study: 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.

Results: 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.

Aim of the study: This study investigated the association between Coronavirus Disease 2019 mRNA vaccination and stroke in Qatar.

Results: The adjusted odds ratio (aOR) for vaccination among cases compared to controls was 0.87 (95% CI: 0.75-1.00). The aOR was 0.74 (95% CI: 0.45-1.23) for a single vaccine dose, 0.87 (95% CI: 0.73-1.04) for primary-series vaccination (two doses), and 0.91 (95% CI: 0.66-1.25) for booster vaccination (three or more doses). The aOR was 0.87 (95% CI: 0.72-1.04) for BNT162b2 and 0.86 (95% CI: 0.67-1.11) for mRNA-1273. Subgroup analyses, considering different durations since vaccination, also demonstrated no association. Subgroup analyses based on nationality, age, number of coexisting conditions, or prior infection status yielded similar results. Subgroup analysis, stratified by stroke type, suggested an association between vaccination and cerebral venous sinus thrombosis (aOR of 2.50 [95% CI: 0.97-6.44]), but it did not reach statistical significance.