Study shows dramatic decline in effectiveness of all three COVID-19 vaccines over timeLos Angeles TimesA study of 780,000 veterans shows a dramatic decline in effectiveness for all three COVID-19 vaccines in use in the U.S.

By the end of September, Moderna’s two-dose COVID-19 vaccine, measured as 89% effective in March, was only 58% effective.

The effectiveness of shots made by Pfizer and BioNTech, which also employed two doses, fell from 87% to 45% in the same period.

And most strikingly, the protective power of Johnson & Johnson’s single-dose vaccine plunged from 86% to just 13% over those six months.