SARS-CoV, a beta virus that causes severe acute respiratory syndrome (SARS)
SARS-CoV-2, which causes COVID-19
How Do Variants Happen?
Coronaviruses have all their genetic material in something called RNA (ribonucleic acid). RNA has some similarities to DNA, but they aren’t the same.
When viruses infect you, they attach to your cells, get inside them, and make copies of their RNA, which helps them spread. If there’s a copying mistake, the RNA gets changed. Scientists call those changes mutations.
These changes happen randomly and by accident. It’s a normal part of what happens to viruses as they multiply and spread.