Appropriate sampling and longer follow-up are required to rigorously evaluate longevity of humoral memory after vaccination

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Presentation Time: 11:30 AM - 12:45 PM
Poster Board Number: B915
Abstract ID: 4968

Presenting Author:
Vitaly V Ganusov , Professor at Texas Biomed. Res. Inst., Univ. of Tennessee

Abstract:

One of the goals of vaccination is to induce long-term immunity against the infection and/or disease. Many studies have followed generation of humoral immunity to SARS-CoV2 after vaccination; however, such studies typically varied by the duration of the follow up and the number of time points at which immune response were measured. How these parameters impact estimates of immunity longevity remains largely unknown. Several studies including one by Arunachalam et al. JCI 2023 evaluated humoral immune response in individuals receiving third or fourth dose of mRNA COVID19 vaccines; by measuring antibody (Ab) levels at 3 time points (prior vaccination, at one and 6 months post re-vaccination), Arunachalam et al. found similar half-life times for serum Abs in the two groups and thus suggested  that additional boosting is unnecessary to prolong immunity  to SARS-CoV-2. I demonstrate that measuring Ab levels at these 3 time points does not allow to accurately evaluate the long-term half-life of vaccine-induced Abs. By using the data from a cohort of blood donors followed for several years, I show that after re-vaccination with vaccinia virus (VV), VV-specific Abs decay bi-phasically and even the late decay rate exceeds the true slow loss rate of humoral memory observed years prior to the boosting. I finally illustrate how mathematical modeling can help determine most appropriate timing and duration of sampling to rigorously determine duration of humoral immunity after vaccination.