J&J Vaccine Recipients Seek mRNA Booster Without CDC Backing (1)

Some people who received the Johnson & Johnson Covid-19 shot in the U.S. are seeking out added doses of a messenger-RNA vaccine, fearing their initial inoculation won’t protect them from the virus.

Demand for the one-and-done J&J shot has suffered in part due to the perception that it’s inferior to the two-dose mRNA vaccines that showed higher efficacy in clinical trials. But it is unclear if mixing vaccines will safely increase protection, and there are fresh signs that J&J’s shot is a strong shield against variants.

Last month, the first suggestion that mixing may be helpful came in a study ...