How COVID-19 'breakthrough' infections alter your immune cells

June 3, 2024
How COVID-19 'breakthrough' infections alter your immune cells.

New research from scientists at La Jolla Institute for Immunology (LJI) suggests people who received COVID-19 vaccines and then experienced "breakthrough" infections are especially well armed against future SARS-CoV-2 infections. 

By analyzing blood samples from study volunteers, the LJI researchers discovered that people who experienced symptomatic breakthrough infections develop T cells that are better at recognizing and targeting SARS-CoV-2, including the Omicron and Delta variants. The researchers describe this increased protection as an "immunity wall." 

Key findings: 

  • Study volunteers who experienced symptomatic breakthrough infections developed T cells that recognized multiple targets on the SARS-CoV-2 viral "Spike" and non-Spike epitopes. 

  • This infection left study volunteers with T cells that were better equipped to recognize mutated regions on new SARS-CoV-2 variants. 

  • Even asymptomatic breakthrough infections boost T cell responses, though the effect was not as significant. 

  • Breakthrough infections also led B cells to produce cross-reactive antibodies against SARS-CoV-2. Most of these antibodies targeted the new viral variants and the original vaccine antigens. 

  • The researchers found no evidence of harmful "T cell exhaustion" in study volunteers who had experienced repeated COVID-19 vaccinations and SARS-CoV-2 infections.