Johnson & Johnson, AstraZeneca COVID-19 Vaccines Share Concerns About Rare Blood Clots

As the FDA and CDC have paused use of the Johnson & Johnson COVID-19 vaccine in the United States, research is ongoing to understand whether cerebral venous sinus thrombosis (CVST) is directly linked to the vaccine.

The AstraZeneca vaccine has faced similar concerns in Europe, said Michael Haydock, senior director of therapy area analysis for cardiovascular, metabolic, and infectious diseases at Informa Pharma Intelligence. In an interview with Pharmacy Times, Haydock said that because researchers do not really know the rate of naturally occurring CVST, they are trying to establish whether vaccine-related rates of the condition are higher.

Because the single-shot approach of the Johnson & Johnson vaccine could potentially accelerate vaccination efforts in the United States, Haydock said the pause in use could significantly slow down the vaccination campaign, especially among young adults. Because younger adults often believe themselves to be at a lower risk, and therefore do not see the vaccines as necessary, any additional risk posed by the vaccines—even if the benefits outweigh the risks—could give young adults a reason to not receive the vaccine. This could be the biggest potential problem, Haydock said.

Despite these concerns, Haydock said he still believes that the benefits far outweigh the risks for both the Johnson & Johnson and AstraZeneca COVID-19 vaccines.