Summary
The startlingly poor performance revealed last week for a COVID-19 vaccine made by the German company CureVac isn’t just a disappointment, it’s a scientific puzzle. The company blames the rapidly changing pandemic virus. But several outside researchers suspect the vaccine’s design is at fault. Many scientists and investors alike had expected CureVac’s candidate, which uses messenger RNA (mRNA) to code for the spike surface protein of SARS-CoV-2, had a good chance of becoming one of the most powerful new weapons against the pandemic. It relies on essentially the same novel mRNA technology as vaccines from the Pfizer-BioNTech collaboration and Moderna, which demonstrated more than 90% efficacy in their trials, and it holds some practical transportation and storage advantages over those rival shots. But interim results from a large clinical trial found it only offered 47% efficacy.