Here are the main COVID variants and everything you need to know about each

As the relentless health crisis continues to evolve, authorities around the world have been using Greek letters to name each COVID-19 variant -- including alpha, beta and the now-infamous delta -- as a more practical way to inform non-scientific audiences. Those names are easier to remember than scientific terms, but it's not so easy to keep track of each variant's impact and known risks as new ones keep popping up every now and then.