You're making a bad-faith argument if you think Kamal Harris and Joe Biden had a major impact on vaccine hesitancy. There's no way anyone actually believes that.
Whether we like it or not, bad leadership has consequences. The bad leadership here is that public officials have been manipulative. In this example, Biden and Harris attempted to undermine the public’s trust in the vaccine simply because they wanted to win an election against a man who was spearheading the rapid creation of a much-needed vaccine. They then flipped the narrative when they won the election and have now been accusing idiot republicans (and Facebook) as being the sole cause of the protraction of the pandemic because of republicans playing politics with vaccine hesitancy and misinformation. The consequences of all this is that many people have lost trust in public officials. And just as Harris/Biden implicitly encouraged resistance to a vaccine that was soon to be encouraged by a republican president, foolish people have adopted the strategy to undermine the democrats’ mission to vaccinate the population with that same vaccine.
I think it would restore trust in public officials if they just came forward and admitted some accountability in the political rivalry that has led to foolish vaccine decisions. Do they not have the moral courage to fob this?