Will Worse Side Effects for Moderna's Vaccine Boost Pfizer's Fortunes?

Three COVID-19 vaccines are currently available to Americans. One of them, however, faces some challenges. Johnson & Johnson won't be able to supply as many doses of its vaccine in the next few weeks as originally hoped due to manufacturing issues at a contractor's facility. Questions about whether the vaccine could cause blood clots on a very rare basis have also arisen.

With these headwinds for J&J, the vaccines developed by Moderna (NASDAQ:MRNA) and Pfizer (NYSE:PFE) (with its partner BioNTech (NASDAQ:BNTX)) are in high demand. Both vaccines have very high efficacy levels. Both Moderna and Pfizer/BioNTech have secured supply deals with the U.S. for 300 million doses each.