European vaccine regulators had major concerns over the quality of early batches of Pfizer's Covid jab, leaked emails reveal

 Major concerns were raised about the quality of early batches of Pfizer's coronavirus vaccine, leaked documents from the EU's medical regulator have revealed. 

Scientists charged with checking the chemicals sent to the bloc for approval last year found doses were of a lower standard than the US drugmaker had promised.

In an email dated November 23, a senior European Medicines Agency official warned of a 'significant difference' in the quality of the vaccines compared to jabs used in Pfizer's clinical trials. 

The cause of the poorer quality was unknown and the impact on safety and efficacy of the vaccine was 'yet to be defined', the email said. Pfizer claims the affected jabs were not rolled out on the continent.

It's unclear if similar quality issues were raised in the UK, where the Pfizer jab is one of two vaccines that has been rolled out to 23million Brits already. Regulators in the EU and UK check every batch of the vaccine before allowing them to be used. 

On the back of the find, EU officials filed two 'major objections' to Pfizer, along with a host of other quality control questions it wanted addressed, before it could approve the vaccine. 

The documents were leaked to the British Medical Journal (BMJ) following a cyber attack on the EU regulator in December. 

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Hundreds of thousands of doses of Pfizer's Covid-19 vaccine being prepared in a factory in Belgium (file image)

While the reason behind the poorer quality of vaccines sent to the EU is unclear, Pfizer's jab is made from extremely volatile genetic material known as messenger RNA (mRNA), which at the time meant it had to be kept at -70C.  

If not stored or transported properly the mRNA can be damaged by other molecules in the environment, including light and temperature. 

Guidance has since been updated to say the vaccine can be kept at normal freezer temperatures for two weeks. Once it arrives at a clinic it can be stored in a fridge for five days before use. 

The EMA found just 55 per cent of the mRNA in the vaccines shipped to the EU were stable and intact, compared to 78 per cent in Pfizer's studies. 

Exactly what effect this has on the vaccines is unclear, but intact mRNA is essential to the potency of the vaccine, experts say. 

The EMA approved Pfizer/BioNTech's vaccine on December 21 and claimed the jab's quality was found 'to be sufficiently consistent and acceptable'. 

However, it's unclear how the agency's concerns were satisfied. 

According to one of the leaked emails dated November 25, an EMA official said: 'The latest lots indicate that % intact RNA are back at around 70-75 per cent, which leaves us cautiously optimistic that additional data could address the issue.'

The emails were part of more than 40 megabytes of classified information from the agency's review that were published on the dark web following the cyber attack.

Several journalists — including from the BMJ — and academics worldwide were sent copies of the leaks.

They came from anonymous email accounts and most efforts to interact with the senders were unsuccessful. 

None of the senders revealed their identity, and the EMA says it is pursuing a criminal investigation.

In a statement issued last night, the EMA said the leaked information was partially doctored but it confirmed the emails were real.

It added: 'Whilst individual emails are authentic, data from different users were selected and aggregated, screenshots from multiple folders and mailboxes have been created, and additional titles were added by the perpetrators.' 

A Pfizer spokesperson told MailOnline the quality issues were ironed out with the EMA and none of the vaccines of concern were rolled out on the continent.

It added that the EMA now double-checks Pfizer's vaccine supply shipments.

They added: 'Following the initial disclosure of a data breach that occurred at EMA, some documents relating to the EMA's rolling review of the Pfizer/BNT vaccine clinical program have been found on the internet.

'Discussions with the regulatory authorities about the vaccine's quality aspects, including specifications, represent a normal component of the regulatory review process. 

'All the topics that emerged during the procedure have been discussed transparently with the agency, in accordance to the normal practices, and all questions have been duly addressed during the review process.

'The positive opinion granted by EMA... on December 21... are results of this process, meaning that all the questions raised during the procedure were addressed satisfactorily and the efficacy, safety and quality of the vaccine could be demonstrated on the data submitted.

'EMA is conducting a full investigation into the cyberattack on its systems.

'It's important to note that each batch of vaccines is tested by the official medicinal control laboratory (OMCL) – the Paul-Ehrlich Institute in Germany – before final product release. 

'As a result, the quality of all vaccine doses that are placed on the market in Europe has been double tested to ensure compliance with the specifications agreed upon with the regulatory authorities. Should a batch not meet these required specifications, the product wouldn't be released for use in Europe.

'As with all vaccines, equivalent quality controls are in place with the U.S. FDA and multiple other regulators around the world where the vaccine has been authorised for use.'

The leaks raise questions about the quality of other mRNA vaccines, including Moderna's jab which is already being rolled out in the US and will be shipped to Britain sometime in the coming weeks. 

Pfizer and Moderna have refused to reveal what percentage mRNA integrity they consider acceptable for vaccines against Covid.

The EMA, US Food and Drug Administration (FDA) stated that specific information on criteria is confidential. 

And the UK Medicines and Healthcare products Regulatory Agency has yet to respond to MailOnline's request for comment.  

Pfizer also declined to comment on what percentage of mRNA integrity it is aiming for, nor would it say what may have caused quality dips in certain batches. 

The lack of transparency from regulators and vaccine makers will raise concerns that similar problems could arise in the future. 

Professor Daan Crommelin, a pharmaceutical expert at Utrecht University in the Netherlands, said there is a lack of understanding about the percentage of intact mRNA needed because it is a brand-new technology.

He added: 'For small, low molecular weight products, the active pharmaceutical ingredient integrity is typically close to 100 per cent.' 

'But for mRNA vaccines? Experience with mRNA integrity is limited.' 

Unlike traditional jabs which scientists have decades of experience in developing, this is the first time mRNA has ever been used in vaccinations.

Scientists say mRNA vaccines are cheaper to make and easier to modify in the face of new variants or viruses.

The process of developing mRNA vaccines is also purely synthetic, meaning scientists don't have to rely on cells from living animals.

Siu Ping Lam, MHRA Director of Licensing, said: 'The observations of lower levels of RNA integrity with certain early batches have been addressed, and are not an ongoing concern.

'We are satisfied that the RNA integrity of all batches used in the UK to date have met the product requirements.'