The blood-clot problem is multiplying

‘Whether the blood issues are ultimately linked to only one vaccine, or two vaccines, or more, it’s absolutely crucial to remember the unrelenting death toll from the coronavirus itself—and the fact that COVID-19 can set off its own chaos in the circulatory system, with blood clots showing up in “almost every organ.” That effect of the disease is just one of many reasons the European Medicines Agency has emphasized that the “overall benefits of the [AstraZeneca] vaccine in preventing COVID-19 outweigh the risks of side effects.” The same is true of Johnson & Johnson’s. These vaccines are saving countless lives across multiple continents.

‘But it’s also crucial to determine the biological cause of any vaccine-related blood conditions. This global immunization project presents a lot of firsts: the first authorized use of mRNA vaccines like the ones from Pfizer and Moderna; the first worldwide use of adenovirus vectors for vaccines like AstraZeneca’s, Johnson & Johnson’s, and Sputnik V; and the first attempt to immunize against a coronavirus. Which, if any, of these new frontiers might be linked to serious side effects? Which, if any, of the other vaccines could be drawn into this story, too? How can a tiny but disturbing risk be mitigated as we fight our way out of this pandemic? And what might be the implications for vaccine design in the years to come?

‘To answer these questions, scientists will have to figure out the biology behind this rare blood condition: what exactly causes it; when and why it happens. This is not an easy task. While the evidence available so far is fairly limited, some useful theories have emerged...

• Theory 1: Platelet problems
• Theory 2: The spike’s the problem
• Theory 3: A suspect sequence
• Theory 4: The mixed bag

Read here (The Atlantic, Apr 17, 2021)

Three different futures for the Johnson & Johnson vaccine

‘Based on what we know so far, the future of the J&J vaccine can fork in at least three different directions. In one, the vaccine flames out; unless many, many more cases come to light soon, this seems unlikely. Either of the other two—in which officials end the pause and return the nation to its regularly scheduled vaccine programming, with or without restrictions on who gets J&J next—are more likely. No matter the outcome, though, today’s announcement won’t quickly be forgotten. Pauses in clinical trials, sprinkled through the past year, have already stoked vaccine hesitancy, skepticism, and outright denialism in many circles. The Johnson & Johnson vaccine, previously stigmatized for being “less effective,” now risks a second label: “less safe.” It’s on the precipice of becoming our country’s grody vaccine; maybe it’s already toppled over the edge. An altered reputation in the U.S. will reverberate throughout the world, and set back the global struggle to contain the coronavirus.

‘If the J&J vaccine does return with the FDA’s blessing, we’ll need to rehabilitate it with clear and nuanced messaging, Gounder and many others told me. A vaccine can be excellent. A vaccine can also carry risks. Both can be true; both have been true, for other shots we’ve used. In this case, the gamble could be very small—and still be well worth it.’

Read here (The Atlantic, Apr 13, 2021)