Efficacy confidence isn't affected, but side effect confidence is.

20% points seems to be the drop as the rapid approval process became a victim hyper-partisanship in the US. The push for a rapid approval has been viewed, by the left, as a political ploy by the right instead of a well-planned & scientifically supported approval process. Early polls about taking a vaccine showed much higher support for it before it was politicized. [0]

Support dropped by 20%. Surprisingly, it dropped by about the same amount for both the political right & left, although support on the left started at a higher level. This may indicate that even people on the right were influenced by the perception of a too-rapid approval process.

[0] https://www.pewresearch.org/science/2020/09/17/u-s-public-no...