The new strain appeared in February in Europe, migrated quickly to the East Coast of the United States and has been the dominant strain across the world since mid-March, the scientists wrote.

In addition to spreading faster, it may make people vulnerable to a second infection after a first bout with the disease, the report warned.

The 33-page report was posted Thursday on BioRxiv, a website that researchers use to share their work before it is peer reviewed, an effort to speed up collaborations with scientists working on COVID-19 vaccines or treatments. That research has been largely based on the genetic sequence of earlier strains and might not be effective against the new one.