Quote Originally Posted by Aimless View Post
The answer to your question "have they thought about the possibility that this is related to the use of birth control" is that they have thought about both possible association with—and risk of confounding by—the use of hormonal contraceptives; it was widely discussed before the EMA's safety signal review, and touched on at the presser immediately following that review. At the time, they said they were looking into it more closely—but they did not have enough data to even speculatively answer the question. It is a particularly important consideration for some of the types of clotting issues that have been reported (eg. CVST), especially because AZN's vaccine has been preferentially administered—in most of Europe—to groups in which a majority are women in age groups where the use of hormonal contraceptives (as well as clotting disorders) is common; in other words, it was known at the time of the initial review that people who might experience this type of clotting problem after vaccination with AZN's vaccine may well be more likely to use hormonal contraceptives (re. the observation that "very often the people who suffer from it are on birth control"—although it might not be appropriate to say "very often" about such rare occurrences). So the very straightforward answer to your question is: yes—they have thought about that possibility, and it is difficult to determine how—or even if—the use of hormonal contraceptives plays into the issue of more straightforward clotting conditions among people who have been vaccinated with AZN's vaccine.

What complicates matters are the rarer cases of more weird and more dangerous clotting problems that were initially thought to resemble DIC but are now thought to resemble HIT, giving rise to the term "VIPIT". There are very few reported cases of this possible complication, and the EMA's latest review (as of a few days ago) could not determine any patterns wrt. risk factors for developing this condition. There are too few cases for anyone to be able to draw any firm conclusions.

The uncertainty is just the reality we have to deal with, when it comes to answering this type of question; it isn't unique to this year or this substance. The straightforward answer to the more important question about whether or not AZN's vaccine is safe enough that the possible risks are outweighed by the overall benefits—at the group level—is: yes.
I have the strong feeling the risk evaluation is done as if the vaccination is done in a situation where the actual pandemic isn't really happening. If people weren't dying in bigger numbers without the vaccine, not pushing ahead might make sense, but people are dying in much bigger numbers (and that's not even taking into account the other side effects of an overburdened health care system).