Watch: How — and why — coronaviruses mutate

Like all viruses, SARS-CoV-2, the virus that causes Covid-19, is mutating all the time. Recently some concerning mutations have emerged: the B.1.1.7 variant first discovered in the United Kingdom, which is thought to be approximately 50% more contagious, and the B.1.351 variant first seen in South Africa, which may also have potential to decrease the efficacy of vaccines. These variants are not believed to lead to more serious disease, but a more transmissible virus can put even more stress on an already overloaded health care system, and ultimately lead to more deaths.

Most of the time when a virus mutates, the resulting variants are benign or even weakened versions of the pathogen. But the coronavirus is spreading practically uncontrolled all over the world, which means it is more likely to evolve into a more efficient version. Over time, it is possible that future mutations could result in a virus that is even more contagious, more deadly, or harder to vaccinate against.

In the video above, find out why, and how, viruses mutate.