About 7 million people have received the single-shot vaccine in the United States. And out of those people, six have reportedly experienced cerebral venous sinus thrombosis (CVST) blood clots as of Tuesday morning. "Right now, these adverse events appear to be extremely rare," the agencies added.
The single shot vaccine was given emergency use authorization by the FDA last week and will provide the federal government with 100 million doses until the end of May. J&J's product is said to be less effective at 62% compared to the two-shot variety manufactured by Pfizer.