Source: WebMD.com
A January 2022 study in Denmark showed no difference in the number of hospitalizations caused by BA.2 compared to BA.1. It also showed that as BA.2 cases went up, BA.1 cases went down. But other countries (Great Britain, Norway, and Sweden) report slower BA.2 increases.
Early studies show that current vaccines and boosters seem to work at least as well against the new Omicron variant, protecting against a first infection as well as against serious illness if you do get infected.
The virus keeps mutating, though. By May 2022, an Omicron subvariant called BA.2.12.1 was on the rise, making up almost 43% of COVID-19 infections in the U.
What Do We Know About Omicron BA.4 and BA.5?
BA.4 and BA.5 are subvariants first detected in South Africa in January and February 2022, respectively. Since then, the number of countries and cases associated with these two variants have spiked rapidly. This includes the U.S. Experts say this might mean it’s more transmissible than other Omicron variants.
While BA.4 and BA.5 are different COVID-19 variants, they share an identical mutation, or change, in their spike protein gene. Spike proteins are what the virus uses to infect cells. And while they're similar to other Omicron variants in some ways, they have more in common with the BA.2 variant. They also have additional mutations that may help them avoid antibodies formed from previous Omicron infections.
The two variants also carry a mutation seen in the Delta variant. This may be why the variant spreads more easily. Experts believe this might make the virus more contagious. The mutation may make it easier for the virus to attach to human cells and dodge immune cells.