SARS-CoV-2 Variants
By mid-2022, most countries have moved past the infection surges from BA.5 (a subvariant of the Omicron variant). However, BA. 2.75 remains a concern for scientists and the medical community. Yet, even as the threat of BA.5 was gradually disappearing, scientists were aware that another sublineage would appear.
Winter is approaching the Northern hemisphere, with potential waves of SARS-CoV-2 variants. The wave of new subvariants is a change in the course of SARS-CoV-2. Previously, one variant was replaced by another. Variant trackers have researched global SARS-CoV-2 sequencing data to identify potential subvariants. Their research discovered there are over a dozen sublineages that are quickly rising. The number of variants has led to a question of which to watch for global and winter surges. But, the rise in subvariants has led to a "COVID soup." The increasing number of subvariants means scientists and researchers can't predict which variant will drive the potential surge in COVID-19 this winter.
Whether scientists refer to these variants as swarms or variant soup, the latest immunity-evasive offshoots of Omicron exceed other SARS-CoV-2 variants. The unprecedented amount of offshoots creates complications when predicting waves of infection. Scientists forecast that the uncertainty may create a "double wave" of infection in some areas. Double waves can occur when an area is coping with a surge of one variant and another rise from a different variant occurs.
Past waves of infection were driven by variants such as Alpha, Gamma, Beta, and Delta. The variants stemmed from specific branches of the SARS-CoV-2 family tree. However, since the emergence of Omicron, several subvariants from it have occurred.
Omicron COVID-19
Subvariants
Variant trackers1 have researched global SARS-CoV-2 sequencing data to identify potential subvariants. Their research discovered there are over a dozen sublineages that are quickly rising. The number of variants has led to a question of which to watch for global and winter surges.
Global Surges
Despite COVID-19 cases decreasing globally, Europe and North America are experiencing a rise in cases from the BQ.1 and BQ.1.1 Omicron variant. In addition, another variant predominately found in Asia is the XBB and XBB.1 variant2.
The variants differ in their point of origin. For example, BQ.1 is a subvariant of BA.5, while XBB is considered a recombinant.
XBB is the result of two COVID-19 strains. The variants exchanged part of their genetic material and formed Centaurus (BA. 2.75) and BA. 2.10.1. Throughout the pandemic, there have been recombinants, but unlike the XBB and XBB.1 strain, they haven't spread too far.
The data collected by the Global Influenza Surveillance and Response System (GISRS)3 reports BQ.1 infection is spreading in Europe. European health officials consider this variant may lead to most COVID-19 cases during the winter. Furthermore, the experts project BQ.1 will be the dominant strain into 2023.
Winter Surge in the United States
The Centers for Disease Control and Prevention's (CDC) COVID Tracker4 predicts the two variants from the BQ strain are likely to surge this winter, consisting of 35% of infections. In early November, approximately 35% of new cases in the United States were from the BQ.1 and BQ.1.1 strain. As the strain spreads throughout California and New York, health officials are warning the rest of the country could be engulfed by the BQ strain this winter.
The CDC estimates the reported cases of COVID-19 will be connected to these strains:
The CDC did not include the potential infection rate for the XBB family strain.
Transmission of XBB, XBB.1, BQ.1, and BQ.1.1
BQ.1, BQ.1.1, XBB, and XBB.1 strains of Omicron have a common denominator. Both variants contain several mutations in their spike proteins.
The mutations in the BQ.1 and XBB's lineage's spike proteins create an issue. The data from researchers shows that the variants spread quicker than their predecessors. However, medical professionals, researchers, and public health officials are tracking the data and don't see an increase in hospitalizations. Also, they have noted that the disease severity appears to remain similar to the other Omicron variants.
Effectiveness of Vaccines Against BQ.1 and XBB Family Strains
The mutations in BQ.1, BQ.1.1, XBB, and XBB.1 provide the potential for these variants to be immune to the protective elements of the current vaccines. Dr. David D. Ho, director of Columbia University's Aaron Diamond AIDS Research Center (ADARC)5, shared results from research studies. The studies illustrated how BQ.1, BQ.1.1, XBB, and XBB.1 evade vaccine-derived and infection-derived immunity. The variants' mutation occurs in the regions that bind to cells and infect. This process increases the subvariants' transmission rate, making them highly infectious.
Dr. Ho and his research team studied blood sera samples from 88 people in five groups. The results found people who were infected with BA.2, BA.4, or BA.5 had the smallest drop in neutralizing antibody levels against BQ.1 and BQ.1.1. Those with three doses of the mRNA vaccines and one dose of the Omicron vaccine had only slightly better antibody protection than those with three doses of the mRNA vaccines.