COVID-19 Variants XBB and XBB.1.5: What You Should Know
Keeping up with new variants of COVID-19 is challenging. Each new subvariant comes from one or two other variants or subvariants. Now with the emergence of XBB and its subvariant XBB.1.5, knowing where these subvariants come from and what they mean to your health is essential.
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.
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XBB
While new cases of BA.5 – and its subvariants BQ.1, and BQ.1.1, an Omicron subvariant, were reported in Europe and America, cases of XBB were increasing in other parts of the world. As a result, the WHO released a statement on XBB as researchers and scientists discovered more about XBB. The report said, “While further studies are needed, the current data do not suggest substantial differences in disease severity for XBB infections. There is, however, early evidence pointing at a higher reinfection risk than other circulating Omicron sublineages.”
XBB Lineage
XBB comes from the BA.2 subvariant of Omicron. Two subvariants of BA.2, BA.2.10.1, and BA.2.75 combined to create XBB. This means the XBB subvariant has genes from two different viruses that infected the same host and exchanged DNA.
Infection Risk of XBB
Dr. Diana Finkel (Department of Medicine, Director of Infectious Disease Fellowship Program, Rutgers New Jersey Medical School) says early findings show XBB may have a higher infection rate than previous Omicron subvariants. Experts continue to study XBB’s reinfection rate.
XBB.1.5
The CDC signaled on December 30th, 2022, that a new subvariant, XBB.1.5, also referred to as Kracken, had emerged. In the four weeks before the CDC released its statement, officials tracked the number of new XBB.1.5 cases. The agency’s COVID-19 Data Tracker saw an increase in new XBB.1.5 (4% to 40.5%) cases beginning December 3rd, 2022, and ending the week of December 31st, 2022.
Professionals in the fields of epidemiology and virology believe XBB.1.5 has the potential to create a surge in COVID-19 cases in the United States. While experts aren’t sure how big the wave is or if hospitalizations could be increased, they continue to monitor it.
Despite the concern of a new subvariant originating in China, public health and medical professionals studying XBB.1.5 say that the XBB.1.5 subvariant came from the United States. Experts first detected the subvariant in New York and Connecticut in late October 2022.
Transmission Risk of XBB.1.5
The risk of being infected by XBB.1.5 is approximately 40% higher than other Omicron subvariants. People infected have a higher chance of passing on the virus to others. Further affecting the risk of becoming infected with XBB.1.5 is its ability to slip past previous defense measures. David Ho, MD (Columbia University) conducted trials on viruses engineered to have the genes of XBB, XBB.1, BQ.1, and BQ.1.1. He compared the viruses against those who were either infected, vaccinated with the original and bivalent vaccines, and those who were infected and had the vaccines. He discovered XBB.1 was 63 times less likely to be neutralized by antibodies found in vaccinated and infected people than the BA.2 subvariant and 49 times less likely to be neutralized when compared with BA.4 or BA.5. Meaning these subvariants can evade vaccines and antibodies built up in your body from a previous COVID-19 infection. Dr. Ho stated that XBB.1.5 holds the same potential as XBB.1 to bypass the protection provided by vaccines or past infections.
Prevention
Despite the increased risk of infection from XBB.1.5, you can still take steps to reduce your risk of infection or the effects of XBB.1.5. The CDC recommends people wear masks when indoors, especially in poorly ventilated or crowded places. The agency also has vaccines and booster shots guidelines on its COVID-19 page.
Christina Sisti, DPS, MPH, MS is a bioethicist and health care policy advocate. She works to create awareness and improve health care policy for those with long-term health issues.