Vaccines developed against SARS-CoV-2 have proven to be highly effective in preventing symptomatic infection. Similarly, prior infection with SARS-CoV-2 has been shown to provide substantial protection against reinfection.  However, it has become apparent that the protection provided to an individual after either vaccination or infection wanes over time.  Waning protection is driven by both waning immunity over time since vaccination or initial infection.  The evolution of new variants of SARS-CoV-2.  Both antibody and T/B-cells levels  investigations correlates of protection post-vaccination or post-infection.  The activity of antibodies and T/B-cells provide insight into the underlying causes of waning protection against new COVID virus variants.  This post summarizes and distills what is currently known about the waning of protection provided by both vaccination and/or prior infection, as well as the current information on the respective antibody and T/B-cell responses to new variants.

Per the Studies CD4 drops from 100% to 78.8 then rises.  CD8 start at 70% rises to 86.7% then drops to 50%.   This is the reason to get the new vaccines when available!

Reference Journal article

Summary of Research on Decrease of Vaccine Effectiveness over time

Timepoint                     T-cell detectable T-cells
≤ 1 month CD4 100% (95% CI 83.9, 100.0)
1–2 months 93.3% (95% CI 70.2, 98.8)
4.5 months 78.8% (95% CI 65.1, 88.0)
6–8 months 91.7% (95% CI 78.2, 97.1)
 ≤ 1 month CD8 70.0% (95% CI 48.1, 85.5)
1–2 months 86.7% (95% CI 62.1, 96.3)
4.5 months 57.4% (95% CI 43.3, 70.5)
6–8 months 50.0% (95% CI 34.5, 65.5)