Europe To Resume AZ Vaccine Use After Safety Review, But Confidence Knocked
Source : 'The Pink Sheet'
Countries in the European Union which had suspended use of AstraZeneca PLC’s COVID-19 vaccine will resume after the bloc’s medicines regulator gave it the all clear.
The European Medicine Agency’s preliminary review concluded that the vaccine remained safe and effective at protecting against the “significant threat” of COVID-19, and in preventing hospitalization and death, with this continuing to outweigh the risk of possible side effects.
However, the agency’s head Emer Cooke said a warning of “rare but very serious” bleeding disorders will be added to the product information. Nine deaths due to these adverse events have been recorded shortly after vaccination – an unusually high level, though its experts said a causal link could not be established.
Of the 13 countries which had paused the vaccine’s use over the past week, Germany, France, Italy and Spain all said they would restart inoculations. Norway and Sweden said they would consider the evidence further, with the latter recording another death shortly after vaccination involving a blood clot.
The decisions to re-start have been welcomed by public health leaders across the continent. Many EU countries are experiencing worrying rises in new COVID-19 cases, and deaths across the 27 member states hit a high daily rate of 2,500 one day last week.
Progress on vaccination also remains slow compared to the US and UK, made worse by limited supplies and an ongoing row between the European Commission and AstraZeneca.
The pharma company and its partner Oxford University have kept a low profile over the last week, but both have now welcomed reviews from the EMA and the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) which restated the product’s benefit/risk profile.
However, there are concerns that public confidence in AstraZeneca’s shot, already low because of rows over supplies and doubts about its effectiveness, could be irreparably damaged, even after the EMA’s reassurances.
The EMA’s Pharmacovigilance Risk Assessment Committee (PRAC) found that the vaccine does not cause an increase in the overall risk of blood clots (thromboembolic events) of a more typical nature in those who receive it.
PRAC chair Sabine Straus said it had ruled out a theory that linked side-effects to specific contaminated batches, stating that further tests had disproved this suspicion.
However, the committee did not rule out a link with very rare incidences of blood clots accompanied by low levels of blood platelets (thrombocytopenia). These rare cases include a condition known as cerebral venous sinus thrombosis (CVST), of which 18 cases were recorded, and seven cases of disseminated intravascular coagulation (DIC), which involves blood clots in multiple blood vessels around the body.
These are rare cases given that around 20 million people in the UK and EEA had received the vaccine as of 16 March.
The agency said the committee experts looked in “extreme detail” at records of DIC and CVST reported from member states, nine of which resulted in death. Most of these occurred in people under 55 and the majority were women. Because these events are rare, and COVID-19 itself often causes blood clotting disorders in patients, estimating a background rate for these events is difficult.
However, based on pre-COVID figures it was calculated that less than one reported case of DIC might have been expected by 16 March among people under 50 within 14 days of receiving the vaccine, whereas five cases had been reported. Similarly, on average 1.35 cases of CVST might have been expected among this age group whereas by the same cut-off date there had been 12. A similar imbalance was not visible in the older population given the vaccine.
As this incidence was higher than expected, Straus said the cases merited further monitoring and investigation.
Recently vaccinated people will now be advised to seek medical attention if they experience any of a number of symptoms including breathlessness; pain in the chest or stomach; swelling or coldness in an arm or leg; severe or worsening headache or blurred vision after vaccination; or blood blisters under the skin.
Quizzed by journalists at the press briefing for possible explanations for the apparent pattern seen in younger women, Straus said the committee would pursue a number of likely explanations. These included a potential link to the use of oral contraceptives, where the increased risk of blood clots is well established.
Michael Head, senior research fellow in global health at the University of Southampton, said it was good to see the EMA reaffirming the vaccine’s safety, alongside the World Health Organization and the UK’s regulator, the MHRA.
He said it remained unclear why many EU countries had chosen to suspend its use while the adverse events were being investigated.
“Withdrawing a vaccine during a pandemic will have other consequences, including leaving people unprotected against COVID-19 when they may otherwise have been immunized,” Head declared. “There may also be a rise in vaccine hesitancy, and that may be difficult to overcome in the short to medium term. We don’t want a situation where people wait for another vaccine to arrive, or worse still, prefer not to get vaccinated at all.”
While questions about safety may now take a back seat, the row over AstraZeneca’s lower-than-expected number of doses has been reignited. European Commission president Ursula von der Leyen has warned again this week it could block vaccine exports to the UK if the EU does not receive its “fair share” of supplies.
By Andrew McConaghie