BA.5 much more infectious than BA.2; Kislaya et al.: "SARS-CoV-2 BA.5 vaccine breakthrough risk & severity compared to BA.2: a case-case and cohort study using Electronic Health Records in Portugal"
by Paul Alexander
“The odds of complete primary vaccination (aOR=1.07, 95% CI 0.93-1.23) or booster dose (aOR=0.96, 95% CI 0.84–1.09) among the BA.5 cases were similar to the BA.2 cases, suggesting no significant differences in vaccine effectiveness against infection for the BA.5 lineage compared to BA.2(Table2).
Higher odds of reinfection were observed in BA.5 cases compared with BA.2 (aOR=1.43, 95% CI 0.92-1.26). Combining vaccination and previous infection status, the aOR of BA.5 infection was 1.70 (95% CI 1.40- 2.05) times higher than for a BA.2 infection, within those with complete primary vaccination and with previous infection. Among those with booster dose vaccination and previous infection, the aOR was not statistically significant (aOR=1.18, 95% CI 0.95-1.47).”