In the final update of a living, rapid review, authors report that antibody levels are sustained for a year or more following infections of the delta or omicron variants of SARS-CoV-2. However, protection against reinfection was weaker and waned more quickly for the omicron variant.
“Most adults had IgG antibodies after SARS-CoV-2 infection at time points greater than 12 months (low strength of evidence [SoE]),” the authors wrote based on evidence available through Aug. 22, 2022. “Although most immunocompromised adults develop antibodies, the overall proportion with antibodies is lower compared with immunocompetent adults (moderate SoE for organ transplant patients and low SoE for patients with cancer or HIV). Prior infection provided substantial, sustained protection against symptomatic reinfection with the Delta variant (high SoE) and reduced the risk for severe disease due to Omicron variants (moderate SoE). Prior infection was less protective against reinfection with Omicron overall (moderate SoE), but protection from earlier variants waned rapidly (low SoE).”