To help you understand XBB and XBB.1.5, this article will discuss their origins as well as what you can do to protect yourself from infection.
Omicron
Because COVID-19 is an evolving virus, several variants and subvariants exist. The most notable of the variants are Delta and Omicron.
Omicron, a variant of the original COVID-19 SARS-CoV-2 virus, remains the dominant variant globally. Unfortunately, while it remains dominant, Omicron continues to evolve into subvariants. The continued mutation of Omicron resulted in several subvariants (sub-lineages), including BA.1, BA.2, BA.5, and BQ.1.
Each of these subvariants has unique mutations. For example, one subvariant, XBB, a subvariant of BA.2, mutated to form XBB.1.5. XBB and XBB.1.5 are becoming increasingly prevalent in America and other countries. The World Health Organization (WHO) reported XBB cases in 35 countries, including the United States, as of October 2022. The WHO declared BA.2 a variant of concern in the winter of 2022.
What is BA.2?
Omicron has mutated to form diverse subvariants. BA.2 is a sub-lineage of Omicron’s BA.1 (BA.1.1.529, BA.1.1, and BA.3). In 2022, BA.2 became the dominant strain of COVID-19 in the United States. The Centers for Disease Control and Prevention’s (CDC) COVID-19 Data Tracker reported that approximately 74% of new cases were linked to the BA.2 subvariant. During the height of BA.2 new cases, WHO stated that the BA.2 subvariant was easier to transmit from one person to another than its “sister” subvariant BA.1.
The WHO declared BA.2 a variant of concern in the winter of 2022. Their recommendation maintained the need to monitor the subvariant. Therefore, BA.2 continues to be classified as a subvariant of Omicron.
The BA.2 subvariant is known as the stealth Omicron variant because its genetic mutations make distinguishing it from the Delta variant difficult. Doctors, public health, and infectious disease officials noted that while BA.2 is more transmissible than BA.1, its symptoms are not more severe.