https://www.siliconvalley.com/2021/04/30/cdc-most-jj-vaccine-side-effects-are-nonserious-17-cases-of-blood-clot-condition/

A new review of Johnson & Johnson Covid-19 vaccine safety monitoring data finds that only 3% of reported reactions after receiving the vaccine are classified as serious — and there have been a total of 17 incidents of severe blood clotting while also experiencing low blood platelet levels.

The report, published on Friday by the US Centers for Disease Control and Prevention, notes that the safety profile of the vaccine so far has been similar to what was seen in clinical trials, but safety monitoring during the vaccine’s rollout quickly identified the blood clot incidents.