AZ trial pause brings unconfirmed link between vaccines, demyelinating syndromes back into spotlight

AstraZeneca’s COVID-19 vaccine trial pause due to a neurological adverse event is reigniting discussion around whether vaccines increase risk of demyelinating syndromes, a question that has been posed many times for many vaccines and overwhelmingly come up negative. 

Tuesday’s news that AstraZeneca plc (LSE:AZN; NYSE:AZN) put a voluntary hold on its Phase III trial of adenoviral vector vaccine AZD1222 due to a serious individual adverse event provided a sobering reminder of the need to get a clear picture on safety before a candidate is authorized for widespread use in healthy individuals, even in an emergency (see “AZ Clinical Hold”)...