For people under 30, particularly women, the risk of blood clots from AZ is higher, while at the same time the risk from coronavirus infection is lower. When there are alternative vaccines available with no evidence of similar side effects, it makes sense to temporarily stop administering AZ/J&J to those groups to investigate if there are any risk factors we can use to predict and protect those who may be most vulnerable to side effects. (It has been suggested that young women on certain types of birth control are at highest risk of blood clots after AZ.)

That said, as some have pointed out, the risk of blood clots is still thought to be very low, even for women under 30, and anti-vax groups as well as the vaccine hesitant may see this news as a sign that it's not safe for anyone to take any vaccine. However, I don't think we as a society should actively try to conceal news or research about vaccine safety so that people don't worry. In my opinion, people have a right to know, and efforts to conceal concerning information often backfire, producing more public distrust.