The World Health Organization(WHO) said on Tuesday that it was waiting for reviews by health authorities of the U.S. and Europe on rare blood clots following inoculation with Johnson and Johnson’s vaccine. 

Reuters said the WHO relayed its position, saying it is closely monitoring the situation. 

The global agency said it was also reviewing global documents and data to see whether there are similar adverse effects in other countries, adding it will take time to finish the reviews. 

The vaccine, developed by Johnson and Johnson’s European pharmaceutical arm, Janssen, is one of the COVID-19 vaccines the WHO approved for emergency use, along with vaccines developed by Pfizer and AstraZeneca. 

Earlier in the day, U.S. federal health authorities recommended a pause in the Johnson and Johnson vaccine’s use following cases of rare blood clots in six recipients.