evidence: Mayo Clinic research finds both inoculations have dropped in efficacy, but Pfizer’s decline has been much steeper; both remain highly effective against severe illness [...] However, one was still far more effective than the other — while Moderna was down to 76 percent, Pfizer was down to 42%. The study was conducted among over 50,000 patients. [...] The Mayo Clinic study found that across multiple states, those inoculated with Pfizer were twice as likely to experience a breakthrough infection despite being vaccinated, as compared to Moderna.