ttps://www.bloomberg.com/news/articles/2021-08-31/moderna-jab-spurs-double-pfizer-covid-antibody-levels-in-study The results, published Monday in a letter to the Journal of the American Medical Association, suggested the differences might be explained by the higher amount of active ingredient in the Moderna vaccine -- 100 micrograms, versus 30 micrograms in Pfizer-BioNTech -- or the slightly longer interval between doses of the Moderna vaccine -- four weeks, versus three weeks for Pfizer-BioNTech.