Pfizer Says Its Antiviral Pill Is Highly Effective in Treating Covid November 5, 2021 Auto Bot antibodies, Clinical Trials, Coronavirus (2019-nCoV), Food and Drug Administration, Merck & Company Inc, Pfizer Inc 0 Pfizer’s is the second pill to show effectiveness against Covid-19, and it is the first purpose-built to attack the virus that causes the disease.