Johnson and Johnson is delaying the rollout of its single dose Covid vaccine in Europe over blood clot fears.

American regulators have already suspended the rollout where six cases have been identified among 7 million doses.

The move comes after one vaccine recipient died and a second woman remains in a critical condition in hospital with a blood clot condition officials think may be linked to the Johnson and Johnson jab.

In a joint statement the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) said the clotting was called cerebal venous sinus thrombosis (CVST).

They said they were "reviewing data involving six reported US cases of a rare and severe type of blood clot in individuals after receiving the J&J vaccine".

Pending further review the American regulators recommend "a pause in the use of this vaccine out of an abundance of caution" to "ensure that the health care provider community is aware of the potential for these adverse events".

Johnson & Johnson has issued a statement saying that safety was its “number one priority”.

The statement read: "We are aware that thromboembolic events including those with thrombocytopenia have been reported with Covid-19 vaccines. At present, no clear causal relationship has been established between these rare events and the Janssen (J&J) Covid-19 vaccine."

The pause in use follows similar concerns following rare cases found in the AstraZeneca vaccine.

Last week, the UK’s vaccine advisory body people under the age of 30 will be offered an alternative Covid-19 jab to the AstraZeneca vaccine.

A review by the MHRA found that by the end of last month, 79 people in the UK has suffered from blood clots following vaccination, with 19 of those people dying.

The regulator stressed that this was not proof that the jab was the cause of the clots but conceded that the link was getting stronger.

Guidance from the government’s vaccine advisory group, JCVI has said that people under 30 under who have already received the jab should go ahead and receive their second dose.

Only people who suffered from blood clots after their first dose should avoid a second vaccine, the MHRA said.