Reporting of Suspected Adverse Reactions Fact Checking. To report an adverse reaction to the vaccine please visit: COVID-19 Vaccine Side Effects & Adverse Events (pfizersafetyreporting.com) Also, Official MHRA side effect and adverse incident reporting site for coronavirus treatments and vaccines | Coronavirus (COVID-19) The side effects to the vaccine is as follows and can be … Continue reading PFIZER-BIONTECH COVID-19 VACCINE – Adverse Reactions – Fact Checking.