Plasma after both SARS-CoV-2 boosted vaccination and COVID-19 potently neutralizes BQ.1.1 and XBB.1.

The SARS-CoV-2 Omicron variants, dominating in the late 2022 COVID-19 waves, have acquired resistance to most neutralizing anti-Spike monoclonal antibodies authorized so far, and the BQ.1.* sublineages, dominant in the western countries, are notably resistant to all authorized monoclonal antibodies. Polyclonal antibodies from individuals both with at least 3 vaccine doses and also recently recovered from Omicron COVID-19 (VaxCCP) could retain neutralizing activity against such new Omicron lineages. Here we reviewed BQ.1.1 virus neutralization data from 740 individual patient samples from 37 separate cohorts defined by boosted vaccinations with or without recent Omicron COVID-19, as well as infection without vaccination. More than 96% of the plasma samples from individuals in the recently (within 6 months) boosted VaxCCP study cohorts neutralized BQ.1.1, XBB.1 and BF.7 with 100% neutralization of WA-1, BA.4/5, BA.4.6 and BA.2.75. The geometric mean of the geometric mean 50% neutralizing titers (GM(GMT 50 ) were 334, 72 and 204 for BQ.1.1, XBB.1 and BF.7, respectively. Compared to VaxCCP, plasma sampled from COVID-19 naïve subjects who also recently within 6 months received at least a third vaccine dose had about half of the GM(GMT 50 ) for all viral variants with percent neutralizations of 79%, 52% and 94% for BQ.1.1, XBB.1 and BF.7, respectively. Boosted VaxCCP characterized by either recent vaccine dose or infection event within 6 months represents a robust, variant-resilient, passive immunotherapy against the new Omicron BQ.1.1, XBB.1 and BF.7 variants.