Pfizer, Moderna turned down J&J request to probe COVID-19 vaccine clotting risks: report

Johnson & Johnson has been privately trying to set up an informal alliance with other COVID-19 vaccine makers that would study potential blood clotting risks tied to some of the vaccines and allow the companies to present a common front when addressing safety concerns raised by the public, according to a report in The Wall Street Journal on Friday citing anonymous sources. However, the sources said that while AstraZeneca was interested in joining forces, Pfizer and Moderna saw no need for group action and have declined.

An advisory panel in the US is scheduled next week to discuss whether or not to lift a pause on Johnson & Johnson's Ad26.COV2.S after six women who received the vaccine developed cerebral venous sinus thrombosis (CVST) with low blood platelets, and one died, out of roughly 7 million doses administered across the country. Similar incidents linked to AstraZeneca's Vaxzevria have also emerged in Europe and elsewhere.

Tarnished by association?

Both Ad26.COV2.S and Vaxzevria use adenovirus vector technology. Meanwhile, Pfizer and Moderna executives said their respective mRNA-based vaccines, BNT162b2 and mRNA-1273, appeared safe, according to the sources cited in The Wall Street Journal report. The sources also indicated that Pfizer and Moderna saw no need to duplicate ongoing efforts by regulators that are already trying to get to the bottom of the blood clotting cases, while one of the companies suggested the perception people have regarding the safety of the mRNA vaccines could be tarnished by association.

According to The Wall Street Journal report, Johnson & Johnson asked whether other companies were seeing the same clot risk, and whether there was any collective interest in looking into it. There was also talk about forming an expert panel to review all blood-clot reports among people who were vaccinated, with Johnson & Johnson looking to assess these using the same methodology.

Meanwhile, AstraZeneca talked with Johnson & Johnson about how all vaccine makers should more closely monitor both vaccinated and unvaccinated populations to better understand the clots, the report said. Further, the UK drugmaker has been looking at data suggesting that the frequency of severe blood clots, including potentially deadly ones in the brain, are a more frequent symptom of COVID-19 itself than previously known. University of Oxford researchers – although not those who partnered with AstraZeneca on Vaxzevria – this week released a non-peer-reviewed study indicating that the risk of clots was far lower among people who took the AstraZeneca, Pfizer or Moderna vaccines than among people who contracted COVID-19. The study did not look at recipients of Johnson & Johnson's vaccine.

Limits of industry solidarity

The Wall Street Journal report noted that the COVID-19 pandemic has led to an unusual amount of collaboration among rival drugmakers, including some even merging their manufacturing capabilities to produce more vaccines. However, the "recent private discussions, among the chief medical officers and other executives…show the limits of the industry's pandemic-bred solidarity," the report said. In September, companies including Johnson & Johnson, AstraZeneca, Pfizer and Moderna signed a pledge aimed at quelling public fears over the rapid development of coronavirus vaccines, saying they would not cut corners when it came to preserving the "integrity of the scientific process" and that the safety of vaccinated individuals would be their "top priority."

Separately on Friday, researchers from Johnson & Johnson published a report in the NEJM disputing suggestions that a "class effect" from adenoviral vector-based COVID-19 vaccines may be to blame for rare blood clots seen in some people who received Ad26.COV2.S.

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