"Abstract: Mass COVID-19 vaccination and continued introduction of new SARS-CoV-2 variants increased prevalence of hybrid immunity at various stages of waning protection. We systematically reviewed waning of post-vaccination neutralizing antibody titers in different immunological settings to investigate differences. We searched published and pre-print studies providing post-vaccination neutralizing antibody responses against the Index strain or Omicron BA.1... Among 26 eligible studies, 65 cohorts (range 3–21 per stratum) were identified... Waning was similar across vaccination regimen and prior-infection status strata but was faster for Omicron BA.1 than Index strains, therefore, more recent sub-variants should be monitored. Wide differences in peak titers by vaccine platform and prior infection status mean titers drop to non-protective levels sooner in some instances, which may affect policy."
"Competing interests: M.M.H. and M.D.K. report research grants from Pfizer (all paid to the institution) for unrelated projects. All other authors declare no competing interests."
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