The safety of coronavirus vaccines has become a major talking point in recent days, particularly after several countries suspended use of the Oxford/AstraZeneca jab.

People across the UK have been urged to get their coronavirus vaccine, despite a growing list of countries temporarily halting AstraZeneca vaccines amid concern around blood clots.

But should you be concerned if you have had or are given the AstraZeneca brand of the Covid-19 vaccine? We've tried to answer your questions.

Is there evidence of the Oxford/AstraZeneca vaccine leading to blood clots?

AstraZeneca has insisted its vaccine is safe, saying a review of available data in more than 17 million people who have been vaccinated across the UK and EU has shown no evidence of an increased risk.

And the Medicines and Healthcare products Regulatory Agency (MHRA), the UK's medicines regulator, said the available evidence "does not suggest the vaccine is the cause" of clots.

These messages were backed up by Professor Anthony Harnden, deputy chairman of the Joint Committee on Vaccination and Immunisation (JCVI), on Monday morning.

He told BBC Breakfast there was "no demonstrable difference" in the number of blood clots seen between the general population and the 11 million who have so far received the Oxford/AstraZeneca jab to date.

"Safety is absolutely paramount and we monitor this data very carefully," he said.

"There are 3,000 blood clots a month on average in the general population and because we're immunising so many people, we are bound to see blood clots at the same time as the vaccination, and that's not because they are due to the vaccination. That's because they occur naturally in the population."

The World Health Organisation (WHO) and the European Medicines Agency (EMA) have also denied the existence of a link between the vaccine and blood clots.

Downing Street sought to reassure people about the safety of the Oxford/AstraZeneca Covid-19 vaccine.

The prime minister'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."

Wymondham & Attleborough Mercury: Prime minister Boris Johnson said there is 'no reason at all to discontinue the vaccination programme'.Prime minister Boris Johnson said there is 'no reason at all to discontinue the vaccination programme'. (Image: PA)

And when asked if he could tell the public that the vaccine is safe during a visit to Coventry on Monday, Boris Johnson said: "Yes, I can. In the MHRA we have one of the toughest and most experienced regulators in the world.

"They see no reason at all to discontinue the vaccination programme... for either of the vaccines that we're currently using. They believe that they are highly effective in driving down not just hospitalisation but also serious disease and mortality.

"We continue to be very confident about the programme and it's great to see it being rolled out at such speed across the UK."

So why have some countries suspended its use?

On Monday, the Netherlands suspended use of the Oxford/AstraZeneca vaccine over concerns about possible side effects. Germany, Italy and France later made the same decision.

The Dutch government said the precautionary move will last until at least March 29, following a similar decision made by the Republic of Ireland.

Denmark, Norway, Bulgaria, Iceland and Thailand have all temporarily suspended their use of the AstraZeneca jab.

The Republic's health minister Stephen Donnelly said use of the Oxford/AstraZeneca jab was being temporarily suspended "based on new information from Norway", in reference to reports of serious clotting in adults in Norway which left four people in hospital.

Wymondham & Attleborough Mercury: Several countries have suspended use of the AstraZenica vaccine over blood clot concerns, though the manufacturer insists it is safe.Several countries have suspended use of the AstraZenica vaccine over blood clot concerns, though the manufacturer insists it is safe. (Image: PA)

These countries have taken these steps despite the EMA's assurance that the vaccine's benefits continue to outweigh its risks and that jabs can keep being administered while it carries out a review into any incidents of blood clots.

It noted last week that there had only been 30 cases reported among almost five million people jabbed in the European Economic Area.

AstraZeneca's chief medical officer Ann Taylor said its review had found no evidence of an increased risk of pulmonary embolism, deep vein thrombosis or thrombocytopenia, in any defined age group, gender, batch or in any particular country.

What do experts say about the greater danger of not having a vaccine?

Professor Andrew Pollard, director of the Oxford vaccine group, said there were "huge risks" from Covid and "if we have no vaccination and we come out of lockdown in this country, we will expect tens of thousands of more deaths to occur during this year".

He said: "A number of countries around Europe are now seeing an increase in cases again. Italy and France and Germany and Poland – all have the start of a new surge in cases.

"It's absolutely critical that we don't have a problem of not vaccinating people and have the balance of a huge risk – a known risk of Covid – against what appears so far from the data that we've got from the regulators – no signal of a problem."

And the UK's national statistician said he has "no doubt" that there will be a further wave of Covid-19 infections in the autumn.

Professor Sir Ian Diamond, head of the Office for National Statistics (ONS), said while people need to understand how the data is moving forward and look at the impact of the "wonderful" vaccine rollout, the virus "isn't going to go away".

He told BBC's The Andrew Marr Show: "I have no doubt that in the autumn there will be a further wave of infections."

What about possible side-effects from the jabs?

Prof Harnden told BBC Breakfast on Monday women were more likely to get side effects from the Oxford/AstraZeneca jab.

Asked whether people might experience some side effects, he said: "Yes, there are. 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.

"They do seem to be more common in women and in younger women.

"With the Pfizer vaccine, which we are given at the moment, it seems to be the reverse – side effects are more likely with the second vaccine.

"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. And don't not have your second vaccine because of the side effects because the second vaccine is likely to be less reactogenic than the first."

Are people likely to need a booster jab later in the year?

Prof Harnden said a booster jab could be rolled out to the nation's vulnerable and elderly in late summer in preparation for a third wave.

Wymondham & Attleborough Mercury: A booster jab is possible in the autumn or winter over fears of a third wave of Covid-19.A booster jab is possible in the autumn or winter over fears of a third wave of Covid-19. (Image: Copyright: Archant 2020)

He told The BMJ's Talk Evidence podcast: "We certainly don't want to see a winter like we've seen this winter – and if we've got new variants circulating and we've got dropping levels of immunity due to the vaccination, then that becomes an imperative to do a booster.

"I think we’re likely to make a bold decision to recommend a booster dose, even if we haven’t got all the evidence of the necessity, just because I think the consequences of not immunising with the booster dose are so big. If it’s proved that it’s needed months later it may be too late."

He added the worries over a third wave and its effect on the vulnerable and the elderly mean it's possible the boosters could be rolled out as early as August or September.

And he believes it is "very difficult to predict" whether the Covid jab will become an annual vaccine.