The European Medicines Agency found a possible link between Johnson & Johnson’s coronavirus vaccine and rare cases of unusual blood clotting disorders “very similar” to those occurring with the AstraZeneca shot but says benefits outweigh the risks.
It recommended a warning should be added to the vaccine’s product information. European Union member states could now “take decisions on how to roll out this vaccine based on their national situation”, the EU commissioner said. South Africa and the US have not yet announced whether they intend to lift their suspensions of the J&J vaccines use, though experts told MedicalBrief that resumption of usage was likely imminent in both countries
The EMA said it had examined eight serious cases of unusual blood clots associated with low levels of blood platelets, including one death, in the US, where more than 7 million people have so far received the vaccine. All had occurred in people under 60, mostly women, within three weeks of vaccination. As with AstraZeneca, most occurred in the brain and abdomen. It said the events should be listed as “very rare side-effects” of the vaccine.
“This is a very rare effect, but it is very important for doctors and patients to be aware of the signs so that they can spot any concerns and seek specialists’ help as soon as possible,” Emer Cooke, the EMA’s executive director, said. “Thousands of people are still dying every day of Covid-19 and these vaccines play an immensely important role in combating this pandemic. The vaccine’s benefits in preventing Covid-19 outweigh the risks of these very rare side-effects.”
The announcement came as the European commissioner in charge of the bloc’s vaccine supplies said he was confident the EU’s 27 member states would have enough doses to fully vaccinate 70% of their adult populations by mid-July. Johnson & Johnson halted the European rollout of its single-dose vaccine last week, a day after deliveries of the shot began, advising governments to store their doses until the EMA had issued guidance on their use.
The Guardian reports that the concerns with the vaccine echo those around the Oxford/AstraZeneca shot, which faced a similar setback last month when several European countries suspended its use temporarily over unusual blood clots in a small proportion of recipients. Most have resumed vaccinations with the AstraZeneca shot although a dozen, including France, Germany, Italy and Spain, are limiting its use to people over 55, 60 or 65, and Denmark has stopped administering it altogether.
Preliminary research released on Tuesday (20 April) from a German team investigating unusual blood clots in people who had the AstraZeneca shot suggests that a number of constituents in the vaccine may contribute to clots in very rare cases. Prof Andreas Greinacher at the University of Greifswald found that proteins and other molecules in the vaccine produced “complexes” which in some people led the immune system to overreact and induce clotting. “My assumption is that this is a class effect of vaccines using the adenovirus,” he said.
Greinacher said it may be possible to reduce the risk of clots by removing proteins that remain in the shots after the manufacturing process and reducing levels of an additive called EDTA, but he stressed that manufacturers would need to look at what changes could be made without affecting safety and efficacy. He said he will be looking at how the Johnson & Johnson vaccine may cause clots after talks with the firm.
Sabine Straus, the head of the EMA’s safety committee, said it was still too early to confirm a common mechanism. “The AstraZeneca vaccine is an adenovirus-based vaccine, as is the Johnson vaccine,” Straus said. “So there are quite some similarities between the two vaccines – but there are also differences. They use different vectors, for example, and also the spike protein is different. So I think it’s too early to draw conclusions.”
Besides the eight cases in Johnson & Johnson recipients, all in the US, the EMA said there had been 287 such incidents in people who had received the AstraZeneca vaccine, including 142 in Europe. The figures for the Pfizer/BioNTech and Moderna jabs were 25 and five.
Straus said that in relation to the number of people who had received the latter two vaccines, which use a different technology known as mRNA, the number of unusual clotting events observed was so far “lower than what we would expect in the general population”.
The EU, whose vaccination programme suffered from early supply shortages and logistical problems but is now picking up speed, has ordered 200m doses of the Johnson & Johnson vaccine. Thierry Breton, the European commissioner who heads the bloc’s vaccine taskforce, said at least 12 member states were confident of being able to meet the commission’s target of vaccinating 70% of their adult population by mid-July.
EMA’s full report
The Guardian report (Open access)
Towards Understanding ChAdOx1 nCov-19 Vaccine-induced Immune Thrombotic Thrombocytopenia (VITT) (Open access preprint)