What we know about Omicron COVID-19 subvariant BA.2

You may have heard of the BA.2 variant of the COVID-19 virus.

BA.2 is a subvariant of Omicron, meaning it’s too genetically related to the original Omicron strain (BA.1) to be classified as a new variant. So far, BA.2 has caused less than 1% of COVID-19 cases in Oregon.

graphic image of Omicron subvariant virus particle, BA.2

What do we know about BA.2?

Based on data from Denmark and the U.K., we know that BA.2 is about 33% more transmissible than the BA.1 Omicron variant. We also know that BA.2 currently represents a very small proportion of cases in the United States. The Centers for Disease Control and Prevention (CDC) estimates that BA.2 currently makes up about 8% of cases in the U.S. (week ending February 26).

Less is known about BA.2 when it comes to the severity of illness it causes, but researchers are gathering new data all the time. According to the World Health Organization, preliminary research and real-life data from Denmark, South Africa and the U.K. suggest that BA.2 doesn’t differ from BA.1 in severity.

Moreover, the WHO also reports that infections caused by the BA.1 Omicron strain seem to provide strong protection from reinfection by BA.2.

BA.2’s future

The future of BA.2 isn’t clear. In some countries, BA.2 surpassed BA.1 as the dominant strain but hasn’t led to more deaths or severe disease. Importantly, Oregon health officials do not expect BA.2 to cause another surge, even if it becomes more prevalent. Currently, approximately 86% of people in Oregon have some level of immunity to COVID-19, thanks to vaccines and boosters, or from previous infection, according to Oregon Health and Science University.

Oregon health officials regularly monitor the circulation of COVID-19 variants across the state. A significant portion of positive test samples are sequenced, which allows scientists to identify variants. Additionally, Oregon officials study samples from more than 40 wastewater sites around the state and can detect virus variants at the community-level. With this kind of surveillance, experts can tell whether one variant is becoming more dominant. If BA.2 suddenly starts causing more cases, OHA will know.

As with the previous COVID-19 variants, the best protection is to get vaccinated and boosted, if eligible, and to wear a well-fitting mask in indoor public spaces.