Phase I Studies of Two Candidate COVID-19 Nanoparticle RNA Vaccines

Despite an enormous worldwide need, no COVID-19 vaccine is available yet. Two companies, BioNTech and Pfizer, collaborated to develop RNA-based vaccines and, working with academic investigators, have now completed phase I studies on two lipid nanoparticle–formulated nucleoside-modified vaccines. One candidate vaccine (BNT162b1) encodes a secreted trimerized receptor-binding domain of SARS-CoV-2; the second (BNT162b2) encodes a modified full-length SARS-CoV-2 spike protein locked in a prefusion conformation. Each vaccine (or placebo) was given in two doses 21 days apart at different dose levels (10 µg, 20 µg, 30 µg) or, for BNT162b1 only, a single dose of 100 µg, to adults aged 18 to 85. The investigators determined safety through 6 months f…