A growing number of countries across the world have suspended use of the Oxford-AstraZeneca vaccine over concerns about its side effects.
The nations have taken action following claims that a handful of people who have had the jab have gone on to develop blood clots.
In Austria a man died 10 days after being vaccinated having been admitted to hospital with pulmonary embolism, the European Medicines Agency confirmed.
A review from Norway's medicines agency showed four new cases of "serious blood clotting in adults", while another death involving a blood clot was reported in Denmark.
And in Italy a 50-year-old man is thought to have died of deep vein thrombosis having had the jab.
More than 11 million Brits have had the Oxford-AstraZeneca jab which has sparked concern that they could face health issues.
But the head of the Oxford University vaccine group Professor Andrew Pollard said that while "safety is clearly absolutely paramount", about 3,000 cases of blood clots occur every month in the UK from other causes.
Prof Pollard said that more than 11 million doses have now been given in the UK, and the MHRA has said "very clearly that they're not seeing any increase in the number of cases of blood clots" over what they would see normally.
On Tuesday, Emer Cooke, European Medicines Agency (EMA) executive director, said there is “no indication” that the jab is the cause of a reported increase in blood clots.
Emer Cooke, European Medicines Agency (EMA) executive director, told a virtual press conference: "I want to also stress at present there is no indication that vaccination has caused these conditions.
"They have not come up in the clinical trials and they are not listed as known side events with this vaccine.
"In clinical trials, both vaccinated people and people who received the placebo have shown some very small number of blood clot developments.
"The number of thromboembolic events overall in vaccinated people seems not to be higher than that seen in the general population."
She added that the benefits of the Oxford/AstraZeneca Covid-19 jab outweighed the risks.
Last week, the World Health Organisation (WHO), the European Medicines Agency (EMA) and the UK's Medicines and Healthcare products Regulatory Agency (MHRA) said there was no evidence of a link between the jab and an increased risk of blood clots.
Peter Openshaw, professor of experimental medicine at Imperial College London, said the decision to pause rollout of the Oxford/AstraZeneca jab could be a "disaster" for Covid-19 vaccine uptake in Europe.
Asked what he would say to those in the UK who are booked to receive an Oxford jab, Prof Openshaw told BBC Radio 4's Today programme: "I really wouldn't be worried at the present time.
"I think it is very clear that the benefits of being vaccinated at the moment so far outweigh the possible concern over this rather rare type of blood clot.
"It really is a completely one-sided argument statistically that we need to be vaccinating.
"I think it is a disaster for the vaccination uptake in Europe, which is already on slightly unsteady ground in some countries."
Asked why he thought the rollout pause had been taken so widely, he added: "I think the committees are probably afraid of not making that decision to pause on the basis that they might be in some way thought culpable if they didn't, but actually these are such rare events."
These are the countries that have suspended the use of the Oxford-AstraZeneca vaccine so far
Austria, Bulgaria, Congo, Denmark, Estonia, France, Germany, Iceland, Indonesia, Ireland, Italy, Latvia, Lithuania, Luxembourg, Netherlands, Norway, Romania, South Africa, Sweden, Thailand and Venezuela.
Ireland's deputy chief medical officer, Dr Ronan Glynn, recommended the vaccine stop being used for now while acknowledging that "it has not been concluded that there is any link" between the jab and the clotting cases reported in Norway.
Berlin's health ministry called it a "precaution" and there would be further investigation after reports of people suffering blood clots in the days and weeks after receiving a jab.
Prime Minister Boris Johnson's official spokesman said: "The Oxford/AstraZeneca vaccine remains both safe and effective, and we urge anybody asked to come forward to receive a vaccine to do so."
There was "no evidence" that blood clots are any more likely to occur following vaccination, the spokesman said.
Data shows that most people will not suffer any side effects after getting the Oxford-AstraZeneca jab.
For those who do, the common ones are usually mild, include a sore arm where you were vaccinated, a headache, feeling achy, feeling sick and being tired.
These tend to last only a day or two and are not a cause for concern, but the NHS says people can take paracetamol if they want to.
If the health problems persist or get worse, then seek medical advice as you would for any other ailment.
Professor Anthony Harnden, deputy chairman of the Joint Committee on Vaccination and Immunisation, said women were more likely to get them from the Oxford/AstraZeneca jab than were men.
"The Oxford/AstraZeneca vaccine - for the first dose - seems to give quite a lot of minor side effects like: a very sore arm; fever; malaise; headache and sometimes chills which may last for up to 48 hours afterwards," he said.
"The message is once you've had your first Oxford/AstraZeneca vaccine - if you do get some side-effects which are unpleasant, take some paracetamol."
He said people should not be deterred from having a second dose.
