A new mutant strain of the coronavirus is even more contagious than the versions that spread in the early days of the pandemic, according to a new study by scientists at Los Alamos National Laboratory. The Los Angeles Times reports the researchers think the new strain can spread faster and make people vulnerable to a second infection after their first. The study was reportedly posted on BioRxiv, a site researchers use to share work before it’s peer-reviewed. It states that the new strain originated in Europe at some point in February, but quickly spread to the East Coast of the United States and has since become the dominant coronavirus strain around the world. The scientists said they felt an “urgent need for an early warning” to ensure that vaccines and drugs that are being developed are effective against the mutated strain—and not just the first versions. If confirmed, the findings will raise fears that the virus can mutate and change in the the same way as the influenza virus, which requires a new vaccine every year.