Omicron subvariant BA.2 continues global rise as experts assess mixed data

A sub-lineage of the omicron coronavirus variant, dubbed BA.2, continues to increase steadily around the globe as scientists, and health officials are still working to understand the risk it poses to public health.

So far, the overall data has been a mix. Some recent laboratory and animal data has suggested that BA.2 can cause more severe disease than the original omicron variant, BA.1. But, so far, that finding isn't bearing out in real-world data. Countries where BA.2 is dominant are not seeing higher rates of severe disease. And many places seeing BA.2 increasing are also seeing cases decline, along with hospitalizations.

While animal experiments have hinted that BA.2 interacts differently with some immune responses than the original omicron variant, so far real-world vaccine data finds two doses and booster doses are just as effective—if not slightly more effective—against BA.2 than BA.1. There is one thing that everyone agrees on, however: BA.2 is a little more transmissible than BA.1, which was already considered ultratransmissible. Studies have consistently found that BA.2 has a growth advantage, and current estimates peg BA.2's transmission as about 30 percent to 40 percent higher than BA.1's. That explains how BA.2 is now chipping away at BA.1's global domination.