COVID Help Desk: Your questions answered on vaccine ingredients, allergies and more By Gwendolyn Wu, Staff writer Information is changing rapidly as the COVID-19 pandemic sweeps the country, infection rates surge and dip and health care providers roll out the coronavirus vaccine across the country. That’s what the Houston Chronicle’s COVID-19 Help Desk is here to get right. Every week, a Chronicle reporter will take readers’ questions about how the virus works and what to expect with the vaccine. What’s in the ingredient list of the Pfizer and Moderna vaccines? The U.S. Food and Drug Administration published the ingredients of both vaccines online as part of their emergency use authorizations. Pfizer-BioNTech's vaccine includes mRNA, lipids, potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodium phosphate dihydrate and sucrose. Moderna's vaccine includes messenger ribonucleic acid (mRNA), lipids, tromethamine, tromethamine hydrochloride, acetic acid, sodium acetate and sucrose.