evidence: Covid-19: Two rare vaccine side effects detected in large global study BMJ 2024; 384 doi: https://doi.org/10.1136/bmj.q488 (Published 26 February 2024) Cite this as: BMJ 2024;384:q488The largest vaccine safety study to date has identified two new, but very rare, side effects associated with covid-19 vaccines—transverse myelitis and acute disseminated encephalomyelitis. [...] The Global Covid Vaccine Safety Project is funded by the US Centers for Disease Control and Prevention to allow the comparison of the safety of vaccines across diverse global populations.