The warning from the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) comes as concern grows over potential blood clotting issues with the jab, which is currently one of two being rolled out in Australia.

MHRA chief executive Dr June Raine told a Downing Street press conference on Thursday night that headache or severe bruising could be sign of a rare blood clot.

There have been five reports in the UK of cerebral sinus venous thrombosis (CSVT) shortly after the patient received the AstraZeneca shot.

“This type of blood clot can rarely occur naturally in unvaccinated people as well as in people with COVID-19,” Dr Raine said.

“A causal relationship with the vaccine has not yet been established and that the rate of occurrence of these CSVT events among the 11 million vaccinated is extremely rare.”

But Dr Raine said as a precaution, the MHRA advised “anyone with a headache that lasts more than four days after vaccination or bruising beyond the site of vaccination after a few days to seek medical attention”.

Dr Phil Bryan, the MHRA vaccine safety lead, earlier said there was less than “one in a million” chance of suffering this type of blood clot based on the number of doses administered in the country, The Sun reported.

The comments came as the European Medicines Agency, Europe’s top drug regulator, confirmed that the AstraZeneca vaccine was safe for use after some 20 countries including France, Germany and Italy suspended the rollout following a handful of deaths and hospitalisations related to blood clots.

EMA executive director Emer Cooke said the regulator was keenly aware that a number of EU member states had paused vaccinations and were waiting for the outcome of the EMA’s review – and that she would get the jab “tomorrow” if offered.

“Its benefits in protecting people from COVID-19, with the associated risks of death and hospitalisation, outweigh the possible risks,” she said.

“The committee also concluded that the vaccine is not associated with an increase in the overall risk of thromboembolic events, or blood clots.”

Ms Cooke said given “thousands of people in the EU die every day – in fact over 2500 were reported one day last week – it really was crucial for EMA to review rapidly and thoroughly all the available evidence, so we made this review our highest priority”.

“We are delivering on that promise today and our responsibility is to come to a conclusion as to whether the benefits outweigh the risks of the vaccines so that countries can make an uniformed decision and increase trust in the vaccine,” she said.

UK Prime Minister Boris Johnson welcomed the news on Thursday night. “They’ve confirmed that the benefits of the vaccine in preventing COVID far outweigh any risks,” he said.

“The Oxford jab is safe, the Pfizer jab is safe, the thing that isn’t safe is catching COVID. I‘m getting mine tomorrow. Get that jab when your turn comes. Let’s get the jab done.”

Earlier this week, health authorities in Australia said they would delay giving the AstraZeneca vaccine to those who are sensitive to anaphylactic responses after four Queensland recipients had alarming allergic reactions to the jab in the last 48 hours.

Queensland Health Minister Yvette D’Ath said there would now be “precautionary measures” to advise those who are anaphylactic to delay getting the jab while those who proceed to get the vaccine who suffer from these conditions will be observed in hospitals afterwards.

“I want to reassure people that we have absolute confidence in our vaccines in Australia, as the Therapeutic Goods Administration has said all along, that there is a risk category there in relation to people who have allergic reactions,” she told reporters on Wednesday morning.

“We expected this, we are prepared for this but we do want to make sure because we are seeing a number of people react to the AstraZeneca that we are letting people know about that and monitoring them for a longer period to make sure that everyone is safe.”

That came after the nation’s chief medical officer attempted to hose down fears over the jab, saying there was “no evidence” it was linked to blood clotting.

Paul Kelly said on Tuesday that “unusual events” were expected in any major vaccine rollout, and that blood clots were “fairly common” with 17,000 reported in Australia annually – but Professor Kelly stressed authorities would “take it seriously … (and) investigate”.

“We do expect to see blood clots at the time when we when vaccinations are given,” he said.

“But this does not mean that an event that happens after vaccination has been given is indeed due to that vaccine. From my perspective, I do not see that there is any specific link between the AstraZeneca vaccine and blood clots, and I’m not alone in that opinion.”

Health Minister Greg Hunt has said the government “clearly and unequivocally” continued to support the AstraZeneca rollout.

“The TGA does not have any evidence of a biologically plausible relationship that could suggest a cause and effect relationship during vaccination and blood clots,” he told parliament.

Independent MP Craig Kelly and Nationals Senator Matt Canavan have this week both called for the AstraZeneca rollout to be paused in Australia.

“I don’t think all the capitals of Europe have been overtaken by anti-vaccine zealots. There is obviously legitimate concerns here,” Mr Canavan told Sky News on Tuesday.

“Given that we are a country where there is not really an imminent threat of coronavirus, I just don’t see how the risk of the vaccine outweighs, or is better than, suspending right now.”

frank.chung@news.com.au

– with NCA NewsWire