I remember them saying the incidence of blood clots in patients who received the Astrazeneca vaccine wasn't higher than that of the general population. (Maybe something's changed?) I don't know what's going on with the J&J. It SHOULD be investigated. None of these vaccines are approved by the FDA (or whatever the British equivalent would be) so they need to be extra watchful. I'm still answering CDC questionnaires regarding side effect of the Moderna one.