BA.1 and BA.2

 BA.2 is a sub-variant of the omicron variant of SARS-Cov-2. It has basically the same collection of mutations as BA.1, the original omicron variant with about 28 others. It was first identified in South Africa on 2021-11-17. BA.2 is more transmissible than BA.1.

On 2022-01-30, I downloaded 7,623,097 records for SAR-CoV-2 sequences from GISAID. I plotted the the development of the variants of interest (VOI) and variants of concern (VOC) over time with plot_named_variants.R available on GitHub.

This messy plot show the growth of omicron (the green dots on the right) as it overtakes delta (the gold dots at the top right). The plot shows log counts of sequences in the GISAID database. Assuming GISAID data is a representative sample of COVID-19 cases, at least in developed countries, the straight line increase indicates that omicron is under going exponential grown.

We can compare the growth of BA-1 and BA-2.

BA_1_2 <- meta_2022_01_30 %>% 

     filter(Pango.lineage == 'BA.1' | Pango.lineage == 'BA.2')

ggplot(BA_1_2) + 
    geom_point(aes(x = Collection.date, y = log(Count), color = Pango.lineage)) + 
    ggtitle("Omicron Sub-variants")  

Again the straight line increase in both sub-variants indicates exponetial growt.