Conspiracy theories like human to human transmission (initially denied by WHO), masks being useful (initially denied when authorities wanted people to not take up the mask supply), the lab leak theory (obviously China got away with it and their gain of function bat coronavirus research was funded by NIH/NIAID), myocardial infarction from vaccines (even if rare, reports of it were suppressed), the denial of the effectiveness of natural immunity, the unnecessary shut down of outdoor parks or schools or whatever else, the rampant fraud in stimulus schemes, and more? The real conspiracy theory is in the rampant abuse of the phrase ‘conspiracy theory’.
The only thing hampering pandemic prevention are there own lies. Turns out if you call everything a conspiracy theory people will eventually start believing them rather than you.