Largest Covid Vaccine Study Yet Finds Links to Health Conditions

Vaccines that protect against severe illness, death and lingering long Covid symptoms from a coronavirus infection were linked to small increases in neurological, blood, and heart-related conditions in the largest global vaccine safety study to date.

The rare events — identified early in the pandemic — included a higher risk of heart-related inflammation from mRNA shots made by Pfizer Inc., BioNTech SE, and Moderna Inc., and an increased risk of a type of blood clot in the brain after immunization with viral-vector vaccines such as the one developed by the University of Oxford and made by AstraZeneca Plc.