Last week, the Senate voted 52-48 to use the Congressional Review Act to repeal the regulations issued by OSHA to mandate vaccines or COVID-19 testing in workplaces with more than 100 employees. The vote generated headlines but the impact of the vote on actual COVID-19 vaccine policy is zero.
The Congressional Review Act allows Congress to pass resolutions of disapproval of executive branch regulations without having to worry about the filibuster in the Senate (yes, the same people who zealously defend the filibuster are happy to see it waived in policy areas where they would like quick Congressional action). It has generally only been successfully used at the beginning of a presidential administration to repeal regulations from the previous president.