FDA (The Food and Drug Administration and Centers for Disease Control and Prevention) recommended a pause in the use of the Johnson & Johnson vaccine on Tuesday as they examine six severe cases of rare blood clots. J&J’s JNJ, -1.34% vaccine is an adenovirus vector-based vaccine that only requires one shot. Clinical trials showed it had 72% efficacy in the U.S.
The two-shot mRNA-based vaccines made by Pfizer PFE, +0.51% and German partner BioNTech SE BNTX, +6.68% and Moderna MRNA, +7.40% make up the majority of shots administered in the U.S., and were about 95% effective in clinical trials. (Mayo Clinic research puts their “real world” effectiveness at closer to 88.7%, still high.)
