The continued success of the global vaccination effort relies upon both the use of safe vaccines and public confidence in their benefit and safety. We need to assess and quantify potential vaccine risks using scientifically rigorous methods in a timely manner for benefit-risk decisions. Uncommon Adverse Events Following Immunization (AEFI) are rare and include outcomes that are delayed and outcomes that occur beyond clinical trial study follow‐up. AEFI, including those among subpopulations excluded from initial clinical programs (e.g., pregnancies, immune-compromised), can only be evaluated in post introduction pharmacovigilance (PIPV) studies. Historically, PIPV has relied on spontaneous reports or passive surveillance for AEFIs. Such passive systems suffer from many weaknesses such as biased/under-reporting, lack of denominators and comparison groups. They can generate hypotheses of new safety concerns but cannot test them to see if they are likely to be caused by vaccines or not.
- Mix-and-match COVID vaccines trigger potent immune response May 24, 2021
- Arterial events, venous thromboembolism, thrombocytopenia, and bleeding after vaccination with Oxford-AstraZeneca in Denmark and Norway May 12, 2021
- The critical role of background rates of possible adverse events in the assessment of COVID-19 vaccine safety April 17, 2021
- The UK Expert Haematology Panel (EHP) has produced guidance on the syndrome of Thrombosis and Thrombocytopenia occurring after coronavirus vaccination April 8, 2021
- Why is it so hard to investigate the rare side effects of COVID vaccines? April 7, 2021