Pfizer and Moderna Decline J&J's Request for Collaborative Research on COVID-19 Vaccine-Linked Blood Clotting Issues

Compiled by Keke

According to a recent report by The Wall Street Journal, Johnson & Johnson contacted Pfizer, Moderna, and AstraZeneca, requesting that they investigate clotting issues associated with COVID-19 vaccines and “provide input on safety concerns.” However, both Pfizer and Moderna declined, asserting that their vaccines are not linked to thrombotic events.

The two pharmaceutical companies believe it is unnecessary to duplicate the investigation by drug regulatory authorities, as they are already studying the issue of vaccines causing blood clots. However, some sources claim that Pfizer and Moderna may also be linked to clotting issues.

To date, the COVID-19 vaccines developed by AstraZeneca/Oxford University and Johnson & Johnson have been associated with very rare but potentially life-threatening blood clotting issues; however, the underlying cause of these clots has not yet been determined.

Moreover, the blood-related adverse events associated with each vaccine vary. The United States has suspended the distribution and administration of the Johnson & Johnson vaccine. The AstraZeneca/Oxford University vaccine has been halted in approximately 20 European countries but has not yet been approved in the United States.

For Johnson & Johnson’s vaccine, the clotting issue manifested as cerebral venous sinus thrombosis (CVST), observed in conjunction with low platelet counts (thrombocytopenia). The reported cases were predominantly among women aged 18–48 years, with symptoms appearing 6–13 days after vaccination.

In cases involving the AstraZeneca/Oxford University vaccine, the reported thrombotic events were deep vein thrombosis (DVT) and pulmonary embolism. It remains unclear whether these two vaccines caused thrombosis, or whether their coagulation mechanisms are entirely identical.

AstraZeneca had previously agreed to collaborate with Johnson & Johnson. The Wall Street Journal pointed out that during the COVID-19 pandemic, cooperation and information sharing among competing pharmaceutical companies far exceeded previous levels.

A Johnson & Johnson spokesperson stated that the company believes collaboration can help address questions regarding blood clots and patient safety. It is also cooperating with regulators in the United States and Europe on specific clotting events. All companies have stated that the benefits of the vaccines, including those from AstraZeneca and Johnson & Johnson, outweigh the risks.

In Johnson & Johnson’s studies, the risk of thrombosis was approximately one in a million, whereas the risk associated with the AstraZeneca vaccine was about five in a million. According to a study by the University of Oxford, the risks for the Pfizer-BioNTech and Moderna vaccines appeared to be around four in a million. Notably, however, approximately 16% of COVID-19 patients face a risk of severe thrombosis, which is roughly ten times higher than the risk associated with the Pfizer-BioNTech and Moderna mRNA vaccines.

Paul Harrison, Professor of Psychiatry at the University of Oxford and head of the Translational Neurobiology Group, stated: “COVID-19 significantly increases the risk of cerebral venous thrombosis (CVT) and exacerbates coagulation abnormalities associated with this infection. The risk posed by COVID-19 is higher than that currently observed with vaccination; this should be taken into account when weighing the risks and benefits of vaccination, even for individuals under the age of 30.”

Although Moderna and Pfizer/BioNTech mRNA vaccines use lipid nanoparticles to deliver mRNA encoding the SARS-CoV-2 spike protein, both the AstraZeneca/Oxford University and Johnson & Johnson vaccines employ common cold adenoviruses as vectors; the Johnson & Johnson vaccine uses a human adenovirus, whereas the AstraZeneca/Oxford vaccine utilizes a chimpanzee adenovirus.

There remains some debate as to whether this “excessive caution” regarding the risk of coagulation is truly “excessive.” Statistically, the likelihood of developing a blood clot is extremely rare.

Kawsar Talaat, an assistant professor in the Department of International Health at the Johns Hopkins Bloomberg School of Public Health, stated, “This may deter people from getting vaccinated, but it is important to consider that this is a completely new vaccine. When safety signals emerge, we pause and investigate, and determine how best to move forward so as to maximize vaccine uptake while also protecting people from adverse events.”

Reference Source: J&J Wanted to Collab on Blood Clotting Investigation, but Pfizer and Moderna Declined