A “stealth” version of Omicron cannot be distinguished from other variants using the PCR tests that public health officials deploy to judge its spread around the world. Stealth Omicron (BA.2) has many mutations in common with standard Omicron, but it lacks a particular genetic change that allows lab-based PCR tests to be used as a rough and ready means of flagging up probable cases.
Both FDA-approved lab-based and at-home tests should detect BA.2, as well as the other Omicron (sub-lineage), BA.1.
This variant has been reported to be 50% more transmissible than the original Omicron variant (BA.1) first found in South Africa which spread around the world in a matter of weeks.
BA.2 has already been detected in California, Washington, New York, Texas, Utah, New Mexico and other states. It will likely overtake Omicron as the dominant variant in America.
It’s too soon to know for sure, but there are concerns that the specific mutations identified with the BA.2 sub-type could make it more contagious or better able to evade vaccines.
Preliminary research in Denmark, where cases involving BA.2 are rising, suggest that the sub-variant may be more contagious than the original omicron strain, which was already the most transmissible known variant to date. The BA.2 sub-type accounted for 20 percent of Denmark’s Covid-19 cases at the end of December, and it jumped to 45 percent of reported cases by the second week of January. Danish Health Minister Magnus Heunicke said this week that the BA.2 sub-variant is now dominant in the country.
So far, there is no evidence to suggest that the sub-variant causes more severe illness or symptoms, but it may be too soon to tell. More research is needed, but early reports show that vaccines are roughly as effective against BA.2 as they are against the original strain of omicron. Vaccines protect against serious illness and hospitalizations.
The United States has the highest levels of hospitalizations in the world right now partly because so many Americans chose not to get vaccinated. Hospitalizations have just peaked in America and are starting on the way down but once BA.2 spreads those numbers will likely again rise because so many people will be getting infected with the stealth Omicron variant.