The UK’s medicines regulator on Wednesday said that under-30s in the country will be offered an alternative to the Oxford/AstraZeneca vaccine due to "evolving evidence” linking it to rare blood clots, even as the European Medicines Agency (EMA) concluded a "possible link" between the vaccine and rare clotting.
The Medicines and Healthcare products Regulatory Agency (MHRA) said that routine monitoring has concluded that there is a "strong possibility" that the AstraZeneca vaccine has caused blood clots in an extremely small number of cases. Its review found that by the end of March, 79 people in the UK had suffered rare blood clots after the jabs – 19 of whom died.
It said that 20.2 million doses of the AstraZeneca vaccine, also being produced in collaboration by the Serum Institute of India as Covishield, had been administered in the UK – which means the overall risk of these blood clots is approximately 4 people in a million who receive the vaccine.
“The Oxford/AstraZeneca vaccine is safe, effective and has already saved thousands of lives,” a UK government spokesperson said.
“The government will follow today’s updated advice, which sets out that, as a precaution, it is preferable for people under the age of 30 with no underlying health conditions to be offered an alternative vaccine where possible once they are eligible,” the spokesperson said.
The MHRA stressed that further investigation is required as there is no proof the jab had caused the clots and reiterated its previous advice that the benefits of the vaccine to protect against Covid-19 continue to outweigh the risks.
“No effective medicine or vaccine is without risk. While the clinical trials of vaccines allow us to assess common effects, very rare effects are only seen when the vaccine is used at scale,” said Dr June Raine, MHRA chief executive.
“I would like to reiterate that this is extremely rare," said Dr Raine.
She said as the balance of risk is in favour for older people, the advice would be for younger people to be offered alternatives by the National Health Service (NHS) – either the Pfizer/BioNTech and Moderna vaccines.
The Joint Committee on Vaccination and Immunisation (JCVI) has accordingly published updated guidelines to say that: “JCVI has weighed the relative balance of benefits and risks and advise that the benefits of prompt vaccination with the AstraZeneca Covid-19 vaccine far outweigh the risk of adverse events for individuals 30 years of age and over and those who have underlying health conditions which put them at higher risk of severe COVID-19 disease.”
“JCVI currently advises that it is preferable for adults aged below 30 years without underlying health conditions that put them at higher risk of severe Covid-19 disease, to be offered an alternative Covid-19 vaccine, if available. People may make an informed choice to receive the AstraZeneca Covid-19 vaccine to receive earlier protection,” it said.
The MHRA advice for those who have received the Oxford/AstraZeneca vaccine and display certain symptoms after four days or more should speak to their doctors.
These symptoms include severe headache, blurred vision, chest pain, leg swelling, shortness of breath, persistent abdominal pain or unusual bruising. The advice for anyone who experiences blood clots and low levels of platelets after their first dose is that they should not have a second dose.
England's Deputy Chief Medical Officer, Professor Jonathan Van-Tam, described the latest developments as a "course correction", which is not unusual in vaccination programmes.
The conclusions of the MHRA, announced in a virtual briefing, came alongside a virtual briefing from the European Medicines Agency (EMA) in Amsterdam which also revealed similar findings and said that the overall “benefit-risk” remains positive for the Oxford/AstraZeneca jabs.
“EMA’s safety committee has concluded that unusual blood clots with low blood platelets should be listed as very rare side effects of Vaxzevria (Oxford/AstraZeneca vaccine),” the EMA said.
“People who have received the vaccine should seek medical assistance immediately if they develop symptoms of this combination of blood clots and low blood platelets,” it said.
The EMA said 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, HIT). It has issued new studies and amendments to ongoing ones to provide more information on this.
The EMA said it carried out an “in-depth review” of 62 cases of cerebral venous sinus thrombosis and 24 cases of splanchnic vein thrombosis reported in the European Union (EU) drug safety database as of March 22, 18 of which were fatal.