Two J&J Shots Offer Least Protection Against Omicron, NIH Finds

Combining two Johnson & Johnson Covid-19 shots offers the least amount of antibody protection against omicron, according to an NIH study on how well mix-and-match boosters work against the highly contagious variant.

The study comes as the omicron strain now accounts for 98% of cases of Covid-19 in the U.S. Public health leaders have stressed the importance of boosters, but most of the data showing that the additional doses increase antibody levels stems from the Pfizer Inc.-BioNTech SE or Moderna Inc. vaccine.

The latest study, which appears on the pre-print server MedRxiv, found most combinations of boosting ...