COVID-19 Continues to Evolve: SARS-CoV-2 Subvariants Outcompete and Elope from Antibodies

Strategic Insights -

Research has revealed that SARS-CoV-2 continues to evolve, causing waves of infections, and it is crucial to understand the characteristics of the virus responsible for its growth advantages. According to a recent study published in Cell Reports, the SARS-CoV-2 Omicron JN.1 subvariants KP.3.1.1 and XEC were outcompeted by LP.8.1 and LP.8.1.1, and other subvariants, such as LF.7.2.1 and MC.10.1, were under monitoring. However, subsequently, NB.1.8.1 and XFG became dominant subvariants. The study found that serum neutralizing antibody titers against LP.8.1, LP.8.1.1, LF.7, LF.7.2.1, and MC.10.1 were similar to XEC in 40 adults, including KP.2 monovalent mRNA vaccine recipients. Notably, NB.1.8.1 and XFG were more evasive of serum neutralization than LP.8.1.1.

Key Takeaways:

  • The SARS-CoV-2 Omicron JN.1 subvariants KP.3.1.1 and XEC were outcompeted by LP.8.1 and LP.8.1.1.
  • Serum neutralizing antibody titers against LP.8.1, LP.8.1.1, LF.7, LF.7.2.1, and MC.10.1 were similar to XEC in 40 adults, including KP.2 monovalent mRNA vaccine recipients.
  • NB.1.8.1 and XFG were more evasive of serum neutralization than LP.8.1.1.
  • The study found that the expansion of NB.1.8.1 and XFG appears correlated with enhanced antibody evasion.
  • Receptor-binding affinity better explained the rise of LP.8.1, unlike most prior SARS-CoV-2 sublineage evolutionary trajectories.
  • The study revealed that LP.8.1, NB.1.8.1, XFG, and related subvariants exhibit different evasion strategies for monoclonal antibodies.

Statistics:

  • 40 adults participated in the study to compare serum neutralizing antibody titers.
  • The study found that serum neutralizing antibody titers against LP.8.1, LP.8.1.1, LF.7, LF.7.2.1, and MC.10.1 were similar to XEC.
  • The receptor-binding affinity of LP.8.1 was the highest among the tested viruses.
  • The study revealed that 12 monoclonal antibodies (mAbs) were used to neutralize LP.8.1 and XFG, MC.10.1 and NB.1.8.1, and LF.7.2.1.

Sources:

  • NewsRx. Researchers from Columbia University Vagelos College of Physicians and Surgeons Describe Findings in COVID-19 (Antibody evasion and receptor binding of SARS-CoV-2 LP.8.1.1, NB.1.8.1, XFG, and related subvariants). Medical Letter on the CDC & FDA. November 2, 2025; p 220.
  • Cell Reports. (2025;44(10):116440).