Durability of cross-neutralizing antibodies 5.5 months after bivalent COVID-19 booster.

We analyzed neutralizing antibodies in samples from ancestral+BA.1 and ancestral+BA.4/5 boosted individuals, collected around 5.5 months after booster. Titers of neutralizing antibodies generally decreased compared to a time point early after the bivalent booster immunization. This was more pronounced for individuals without infection history and for recently emerged omicron variants.