Alpha, beta, gamma, delta, omicron: The names of the worrying variants of SARS-CoV-2 are collective terms for different lineages and subvariants. The more people become infected with the corona virus, the greater the likelihood that the variants will continue to change and split. By far the largest collection of sub-variants can currently be found in Delta. Three lines are known for Omicron: BA.1, BA.2 and BA.3 – plus one sub-line, BA1.1. The BA.2 line is now attracting increasing attention. She appears to have a fitness advantage over BA.1, the previously dominant Omicron line, and is probably even more contagious. There’s also some evidence that it’s a better immune escape variant.
BA.1 and BA.2 differ by fifty amino acids. That’s twice as many differences as between alpha, beta, gamma and delta. A working group led by Kei Sato from the University of Tokyo, which uploaded a BA.2 profile to the preprint server bioRxiv a few days ago, believes that the sub-variant deserves its own Greek letter.