However, circulating IgA responses remained stronger against Wuhan-Hu-1 FLS even after Omicron breakthrough infection following two (median OD ± IQR, 1.22, 1.10–1.43 vs. 0.98, 0.87–1.25, p = 0.0010) or three (0.87, 0.61–1.42 vs. 0.67, 0.48–1.23, p = 0.0003) vaccinations (Figure 4a). Here, CD79A is linked to infection.