With hundreds of COVID-19 vaccine candidates in various stages of development and approval, an understanding of any potentially serious adverse events is vital to ensure vaccine acceptance and confidence.

Our new reference page explores vaccine-associated enhanced disease (VAED). It occurs when a more severe presentation of disease develops in an individual who has previously been immunised, compared with when an infection occurs without prior vaccination. VAED has previously been associated with dengue fever infection; RSV, MERS and SARS-CoV-1 vaccine candidates; as well as a measles virus.

It is a theoretical risk only when considering COVID-19 vaccine candidates however as a result, the possibility of VAED has been closely monitored during all stages of clinical trials for COVID-19 vaccine candidates.

For further information please refer to our reference page:

MVEC: Vaccine-associated enhanced disease (VAED)