At today's VRBPAC meeting they shared the data and analysis on the Vaccine Safety Datalink stroke signal seen among people 65 and older after the Pfizer bivalent booster. Here is the most informative chart from the presentation.
As you can see there was a signal observed in the first couple weeks after vaccination. The rate ratio compared to the comparator group was 1.47 with a 95% confidence interval of 1.11 to 1.95. But interestingly the signal attenuated over time during the analysis period. And there was no signal seen for Moderna or for people under 65. Perhaps suggesting that there were confounders causing the signal.
At this point there is no indication it is a real safety signal- it has not been observed in other safety systems and this safety signal is occurring under limited data. Importantly this has not been seen with the Moderna bivalent booster. So the FDA and CDC will continue collecting data on this and will update recommendations accordingly. As of now recommendations are unchanged with the Pfizer booster- eligible people should get it.