The reason for the break is six reported suspected side effects in the form of blood clots, which are being investigated by the authorities.

All cases involve women between the ages of 18 and 48, one of whom has died and one is being cared for with serious injuries.

To date, nearly seven million Americans have received the vaccine, which is taken in one dose.

The stop is described by US authorities as a precautionary measure.

Bergström: Awaiting EMA

The European Medicines Agency (EMA) is already investigating a possible link between the vaccine and blood clots.

- We have to wait for the EMA's evaluation and then the Swedish Public Health Agency has to decide on any recommendations for Sweden, says Sweden's vaccine coordinator Richard Bergström in an SMS comment to SVT.

The first deliveries of the vaccine to the EU are expected to arrive during the week under the name Janssen's vaccine, developed by Johnson & Johnson's Dutch subsidiary Janssen.