The US halt has indirectly put an end to any hope of supplies from J&J helping to boost the sluggish vaccine rollout in Europe; on the contrary, the campaign could slow further, some fear. Alongside the US discussion, the healthcare giant said it has been been reviewing the clotting incidents with the European Medicines agency and has decided to “proactively delay the rollout of our vaccine in Europe.”

A day earlier, J&J had supplied an unquantified number of first doses to Brussels, without indicating whether it would come close to meeting its obligations to deliver 55 million doses during the second quarter.

The clot issues are not expected to affect the US vaccination program significantly.  President Joe Biden’s Covid-19 response coordinator Jeff Zients said the country has more than enough supply to continue the current pace of vaccinations of 3 million shots per day, and Pfizer CEO Albert Bourla said Tuesday that its plants could deliver 300 million doses more of Comirnaty ahead of schedule.

Explaining the health authorities’ decision to pause, Anne Schuchat, principal deputy director of the CDC, and Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said, “It it is important to ensure that the healthcare provider community is aware of the potential for these adverse events and can plan for proper recognition and management due to the unique treatment required with this type of blood clot.”

While saying it was working with health officials on the matter, J&J stressed that, at present, “no clear causal relationship has been established between these rare events and the vaccine,” developed by its Janssen subsidiary.  

US reports said six women aged 18 to 48 who had received the shot developed a cerebral venous sinus thrombosis (CVST) with low blood platelets six to 13 days after being vaccinated. The EMA’s Pharmacovigilance Risk Assessment Committee (PRAC)  had said last weekend that capillary leak syndrome, a condition in which blood vessels leak into muscles and body cavities could be involved.

In October 2020, the US company paused all clinical trials with its Covid shot candidate –including the just begun Phase 3 clinical trial – citing an unspecified adverse event.  The EMA’s statement referred to that case as the same type of clotting disorder that popped up in the US rollout. The October incident occurred shortly after AstraZeneca in September paused its own Phase 3 trial after a neurological event that was believed to be transverse myelitis.

J&J’s adverse events said similar to AstraZenca’s

The adverse events seen in the US are said to be similar to those with AstraZeneca’s vaccine in Europe – this has not yet been rolled out in the US, where it is still being studied by the FDA. Both companies’ products are based on an adenovirus used as a viral vector to trigger an immune response. In AstraZeneca’s case the vector is an inactivated chimpanzee virus, in J&J’s case a human adenovirus.

Johnson & Johnson was already facing worldwide supply problems with its Covid vaccine, due partly to an incident at the Baltimore, Maryland, plant of CDMO Emergent Biosciences, which up to then produced the vaccines of both the New Jersey healthcare giant and the Anglo-Swedish drugmaker.

At least 15 million Janssen doses earmarked for the US were ruined by workers before the US government handed control of the Emergent plant to J&J and forced AstraZeneca to look for another supply partner. The gap was breached in some cases with ingredients made in Emergent’s Amsterdam facility.

As of Apr.11, the EMA said it had received reports of 222 cases of usually rare clotting problems during vaccinations in both the European Economic Area and the UK, where 34 million people had received the AstraZeneca vaccine. Not widely reported were seven cases of CVST in German vaccinations with BioNTech/Pfizer, which reports said were within the statistical average.

In two separate studies of the AstraZeneca incidents recently published in detail by The New England Journal of Medicine, teams from Germany and Norway found that people who developed blood clots after vaccination had produced antibodies that activated and decimated their blood platelets. Younger people, they said, appear more susceptible to the condition, they said, but as yet no relevant pre-existing health conditions have been identified as potentially involved.

Andreas Greinacher of the University of Greifswald,  one of the German study’s authors, said it was likely that those who developed the clotting disorder had individual co-factors that predisposed their immune systems to make ”powerful, misdirected antibodies” in response to the vaccine. He said there is “clear evidence” that the AstraZeneca vaccine can trigger this condition in rare cases; however, there is no way to predict whom it will affect.

The German researchers said they believe that specialized blood tests can diagnose the disorder and distinguish it from other, more common clotting problems unrelated to the vaccine. Both the German and the Norwegian teams suggested that the condition could be treated with an intravenous immune globulin.

According to the latest count, Germany, the Netherlands, the Philippines, Portugal, Ireland and Spain are recommending that the AstraZeneca vaccine be given only to people over 60. Canada and France have limited it to those over 55, Australia, to those over 50 and Belgium to people over 56. The UK is giving it only to those under 30. Cameroon, the Democratic Republic of Congo, Denmark and Norway have halted use of this vaccine, at least temporarily.

Author: Dede Williams, Freelance Journalist