AstraZeneca vaccine's causal link to blood clots not proven, says European Medicines Agency

AstraZeneca's (AZN.L) share price continued to remain under pressure even as the European Medicines Agency (EMA) reiterated on Wednesday the benefits of the company's COVID-19 vaccine far outweigh the risks. This comes following reports of possible links of the vaccine to blood clots.

Meanwhile, the UK has said adults under 30 should be offered an alternative vaccine instead of the AstraZeneca jab if there is one available in their area and they are not at high risk of COVID.

AstraZeneca's stock was down 1% on Wednesday afternoon.

"COVID-19 is associated with a risk of hospitalisation and death. The reported combination of blood clots and low blood platelets is very rare, and the overall benefits of the vaccine in preventing COVID-19 outweigh the risks of side effects," the EMA said.

It added that very rare cases of unusual blood clots should be listed as a side effect, but that the vaccine is effective and should continue to be used.

"EMA is reminding healthcare professionals and people receiving the vaccine to remain aware of the possibility of very rare cases of blood clots combined with low levels of blood platelets occurring within two weeks of vaccination," it said in a statement.

"So far, most of the cases reported have occurred in women under 60 years of age within two weeks of vaccination. Based on the currently available evidence, specific risk factors have not been confirmed," it added.

It also said that one plausible explanation for the combination of blood clots and low blood platelets is an immune response, leading to a condition similar to one seen sometimes in patients treated with heparin (heparin induced thrombocytopenia).

WATCH: EMA says AstraZeneca COVID vaccine's benefits outweigh risks

EMA’s safety committee has requested new studies and amendments to ongoing ones to provide more information and "will take any further actions necessary."

READ MORE: Under-30s in UK will not be given AstraZeneca COVID vaccine due to ‘very rare’ risk of blood clots

Ahead of the EMA's briefing, Spain’s Castile and Leon region suspended the use of the AstraZeneca COVID-19 vaccine for the second time.

“We can’t run the risk of continuing to use the product knowing that there are questions about who it should be used for and risking adverse reactions,” Veronica Casado, regional health minister told local press.

Meanwhile in the UK, more than 31 million people have already had a first vaccine dose and more than 5 million people have received their second jab. These are either AstraZeneca or Pfizer (PFE).

The UK has also purchased 17 million doses of the Moderna (MRNA) jab, enough for 8.5 million people. Rollout of the vaccine has begun in Wales on Wednesday and is expected in England in the next few days.

June Munro, CEO for the UK's Medicines and Healthcare products Regulatory Agency, has also said the benefits of the AstraZeneca vaccine continue to outweigh the risks for “the vast majority of people.”

She said up to 31 March there had been 79 cases of this condition, with 19 deaths. Three of the 19 people who died were under the age of 30.

Earlier it had been reported that a trial of the vaccine on children in the UK has been halted until there is more clarity from regulators about the jab's possible link with rare blood clots in adults.

Earlier Speaking to The Telegraph, senior government adviser Dr Maggie Wearmouth said the rollout for younger people in the UK should be paused until regulators issue clear guidance on its safety. She said slowing down the rollout may be crucial to maintain public trust and confidence.

Professor Andrew Pollard from the University of Oxford told the BBC that although "there are no safety concerns in the paediatric clinical trial, we await additional information from the MHRA on its review of rare cases of thrombosis/thrombocytopaenia that have been reported in adults, before giving any further vaccinations in the trial."

As Astrazeneca's woes continue, the Netherlands became the latest country to pause rollout of its jab over the weekend amid concerns about possible blood clotting complications.

Last week, some cities in Germany temporarily halted the vaccine for people under the age of 60, while Canada has suspended its use for those under 55.

And the company’s ties with the EU have also been strained: the European Commission has blamed pharmaceutical companies — primarily AstraZeneca — for not delivering the promised doses to the EU.

WATCH: Oxford pauses UK trial for COVID-19 vaccine on children

Last week, some cities in Germany temporarily halted the vaccine for people under the age of 60, while Canada has suspended its use for those under 55.

And the company’s ties with the EU have also been strained: the European Commission has blamed pharmaceutical companies — primarily AstraZeneca — for not delivering the promised doses to the EU.