The impact of immune history and variant on SARS-CoV-2 viral kinetics and infection rebound
The combined impact of immunity and SARS-CoV-2 variants on viral kinetics during infections has been unclear. To address this gap, we characterized 2,964 infections in the National Basketball Association occupational health cohort. Over half remained potentially infectious (cycle threshold (Ct)<30) five days post detection, with minimal differences by variant and vaccination history. Only 7/1032 infections (0.7%) showed viral rebound, defined as 3+ days with Ct<30 following an initial clearance of 3+ days with Ct≥30. Pre-booster antibody titers and symptoms predicted peak viral RNA and clearance rates. Boosted individuals with Omicron BA.1 infections were more likely to have low pre-booster antibody titers and cleared their infections more slowly than non-boosted individuals. Since booster vaccination protects against infection, these longer clearance times suggest viral clearance takes longer in individuals with less infection protection. The shifting landscape of viral kinetics underscores the need for continued monitoring to optimize clinical and public health interventions.