CHMP5 and infection: Early estimates show that in adults aged 18–49 years, the effectiveness of a bivalent mRNA booster dose (with mRNA encoding primary spike protein antigen and BA.4/BA.5 spike protein) given 2–3 months earlier compared to no bivalent booster was 52% against symptomatic infection with the BA.5 Omicron subvariant and 48% against infection with XBB/XBB.1.5 [147].