WHO official calls blood clots 'very rare'

GENEVA - A top World Health Organization expert on vaccines says people should feel reassured that even if health authorities turn up a link between blood clots and the AstraZeneca vaccine, such cases are "very rare.”

Dr. Kate O’Brien, who heads WHO’s department of immunizations and vaccines, said the U.N. health agency and the European Medicines Agency are trying to investigate the possibility of a link between blood clots and the AstraZeneca shots. The potential side effect has prompted some countries -- mostly in Europe -- to temporarily suspend use of the AstraZeneca vaccine.