Document reveals safety concerns over AstraZeneca vaccine trial in children

Newly released documents have raised questions about the United Kingdom’s decision to allow a clinical trial of the AstraZeneca COVID-19 vaccine involving children as young as six to continue in 2021, despite concerns among government advisers about a rare but potentially life-threatening blood-clotting condition.

The documents, reportedly first brought to public attention by GB News on Monday, contain minutes of a May 21, 2021 meeting of the Commission on Human Medicines (CHM), the advisory body responsible for providing the UK government with expert guidance on the safety, efficacy and quality of medicines.

The meeting considered the risk of vaccine-induced immune thrombotic thrombocytopenia (VITT), a rare condition involving blood clots and low platelet counts that was associated with the AstraZeneca COVID-19 vaccine.

According to the partially redacted minutes, the committee discussed what it described as a “very small but potentially very serious risk” associated with the condition.

Despite the concerns, the Paediatric Medicines Expert Advisory Group reportedly agreed that the clinical trial involving 262 children aged between six and 17 should proceed.

The document indicated that at least one participant argued that the study should be allowed to continue, despite acknowledging that there was often no successful intervention available for VITT.

The revelations have renewed scrutiny of the regulatory decisions surrounding the vaccine’s use in children, particularly because the minutes reportedly acknowledged that the direct benefit of vaccination for children was relatively remote and that the benefit-risk balance was low.

The clinical trial had been temporarily paused in April 2021 following reports of extremely rare blood-clotting events associated with the vaccine.

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Regulators defend decision to continue trial

The UK Medicines and Healthcare products Regulatory Agency (MHRA) has defended the regulatory scrutiny applied to the trial after the safety concerns emerged.

Alison Cave, the agency’s chief safety officer, told The Defender that emerging safety information, including concerns about thrombosis with thrombocytopenia and the benefit-risk assessment of further vaccination among trial participants, was subjected to regulatory and independent expert scrutiny after the study was paused.

She said decisions were made based on the evidence available at the time and remained under review as additional information emerged.

Cave added that the safety and interests of clinical trial participants were central to the regulatory process.

However, the reported minutes have attracted criticism from some medical professionals who believe the trial should have been halted.

Dr Angus Dalgleish, a professor of oncology at City St George’s, University of London, said he was surprised that the committee allowed the study to continue despite the potential severity of the blood-clotting condition.

He described the decision as negligent, arguing that the risk should have prompted an immediate halt to vaccination of children in the trial.

The clinical trial was launched in February 2021, at a time when healthy children were generally considered to face a relatively low risk of severe COVID-19 illness.

According to the report, the study focused primarily on assessing the vaccine’s safety profile rather than establishing its effectiveness in preventing infection among children.

Concerns over second doses

Further questions have emerged over the administration of second doses to children participating in the trial.

GB News cited a study published in The Lancet in June 2022, which indicated that participants received their second AstraZeneca vaccine dose 112 days after the first.

This means the second doses were administered approximately two months after the May 21, 2021 meeting at which advisers discussed the blood-clotting concerns.

The Lancet study stated that the MHRA’s Clinical Trials Unit approved the second doses following a review.

The report also cited figures showing that, by the time of the May 2021 meeting, the UK medicines regulator had received 332 reports of the rare blood-clotting condition associated with the AstraZeneca vaccine, including 58 deaths.

By November 2022, the number of suspected cases had reportedly increased to 445, including 81 deaths.

The figures formed part of the wider safety concerns surrounding the vaccine, although reports of suspected adverse reactions do not, by themselves, establish that the vaccine caused every reported event.

Medical experts question risk-benefit assessment

Brian Hooker, chief scientific officer of Children’s Health Defense, criticised the decision to continue the trial, arguing that the safety reports available at the time should have prompted regulators to reconsider the participation of children.

He maintained that the AstraZeneca vaccine should not have been administered to children given the reported adverse events.

Karl Jablonowski, a senior research scientist with the organisation, also questioned the regulatory assessment, claiming that medical literature available before the May 2021 meeting had already raised concerns about cardiovascular complications associated with COVID-19 vaccination.

The trial’s results were subsequently published in the journal Vaccine. The study identified five serious adverse events and four adverse events of special interest, although its investigators concluded that none was related to the vaccine.

The reported findings have also drawn attention to data obtained through freedom of information requests, which indicated that the MHRA received 48,472 reports of adverse events involving heart conditions following AstraZeneca vaccination in 2021.

Such reports are part of vaccine safety monitoring and do not necessarily establish a causal relationship between vaccination and the reported medical conditions.

UK, European countries restricted vaccine use

The controversy also comes against the background of decisions by the UK and several European countries to restrict or suspend the use of the AstraZeneca vaccine among certain population groups in 2021.

In April that year, the UK’s Joint Committee on Vaccination and Immunisation recommended that people under 30 who had not received their first dose should be offered an alternative vaccine where available.

The changes followed reports of rare blood-clotting events among people who had received the AstraZeneca vaccine.

Several European countries, including Denmark, Norway and Iceland, had suspended the vaccine’s use in March 2021. France, Germany, Italy, the Netherlands, Spain and Sweden also introduced suspensions or restrictions during the period.

AstraZeneca vaccine withdrawn from market

The safety debate continued in subsequent years, with legal action brought by people who alleged that they suffered injuries after receiving the AstraZeneca vaccine.

More than 80 lawsuits were reportedly filed in the UK over alleged vaccine-related injuries.

In 2024, AstraZeneca withdrew its COVID-19 vaccine from the market, attributing the decision to a decline in global demand rather than safety concerns or the legal challenges.

The latest disclosure has revived debate about transparency in vaccine regulation, the handling of emerging safety signals and the standards applied when clinical trials involve children.

While critics argue that the newly released minutes raise serious questions about the decision to continue the trial, the MHRA maintains that the available evidence was subjected to regulatory and independent expert scrutiny and that decisions were based on the information available at the time.