Since the beginning of the year the CDC has been propagating false science, publicly claiming that COVID vaccines protect people previously infected when there's no evidence of that

"Rep. Massie: And instead of fixing it, they proposed repeating it and just phrasing their mistake differently. So, at that point, right now I consider it a lie. I think the CDC is lying about the efficacy of the vaccine based on the Pfizer trials, for those who have already had the Coronavirus." 

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Massie continues to tweet his frustration as recently as Mar 20.