http://www.newsweek.com/stealth-omicron-meaning-explained-ba-2-covid-variant-subvariant-us-cases-1673022

The Omicron BA.2 sub-type continues to attract attention as it spreads in various parts of the world including the U.S.

In several news reports and even by some healthcare experts, BA.2 has sometimes been referred to as "stealth Omicron."