The COVID virus Omicron BA.4 and BA.5 variants that fueled infections through most of 2022 are being replaced by new, related subvariants BQ.1 and BQ.1.1. These new subvariants have additional changes (mutations) in their spike protein that increase infectivity and also reduce sensitivity to current monoclonal antibody therapies.
For most of us who are fully vaccinated, including the bivalent booster targeting the Omicron variants (you have gotten this booster, right?), these new subvariants are not a big concern. Paxlovid remains effective against them, and it is the CDC-recommended therapy for most of us at risk of serious infection. However, some individuals cannot take Paxlovid because of poor kidney function or drug interactions with a needed medication. In addition, individuals with compromised immune systems have poor responses to vaccines and have been dependent upon monoclonal antibodies that no longer work against these new subvariants. Think of transplant recipients and patients on cancer therapy as examples of the estimated 3-5% of US citizens with limited treatment choices for COVID subvariant infection.
There are a couple of options for these vulnerable individuals. Clinical trials of new monoclonal antibodies directed at more conserved regions of the spike protein are underway, and promising preclinical study results have been reported. These should recognize the new subvariants. The older, intravenous-administered antiviral Remdesivir is an available option for those who cannot take Paxlovid.
The chess match between the virus and the immune system will continue. New variants will arise as the virus seeks to evade immune responses triggered by vaccines or natural infection. There will be no checkmate.