Oxford pauses UK trial of COVID-19 vaccine on kids

A UK trial testing the effectiveness of AstraZeneca's COVID-19 vaccine on children and teenagers has been paused.

Oxford University said on Tuesday it had put the trial on hold while it waits for more data on a possible link between the vaccine and rare blood clots.

The trial's disruption is just the latest blow for AstraZeneca's vaccine - once hailed as a milestone in the fight against the pandemic.

Oxford University said while there were no safety concerns in the pediatric trial, it would await guidance from the UK drugs watchdog before administering any more shots.

The European Medicines Agency is expected to announce this week the results of a review into the vaccine and its potential link to an extremely rare brain blood clot known as cerebral venous sinus thrombosis.

A high proportion of the reported cases were among younger women - but many experts say there's no definitive evidence yet of a particular risk for that group.

The World Health Organization says it expects no changes to its assessment that the shot's benefits outweigh any risks.

Dozens of countries have approved use of the vaccine and millions of doses of it have been safely administered around the world.

However, Germany, France and the Netherlands have restricted it use to their older populations due to concerns about blood clots.