EPIDEMICSmRNA Vaccine Beats Infection for Key Defense against COVID-19: Stanford Scientists
The Pfizer/BioNTech mRNA vaccine directed at COVID-19 is much better than natural infection at revving up key immune cells called killer T cells to fight future infection by SARS-CoV-2, the virus that causes COVID-19.
The Pfizer/BioNTech mRNA vaccine directed at COVID-19 is much better than natural infection at revving up key immune cells called killer T cells to fight future infection by SARS-CoV-2, the virus that causes COVID-19, Stanford Medicine investigators have found.
The scientists also showed, in a study published online in Immunity, that getting infected by SARS- CoV-2 before getting vaccinated lowers the vaccineʼs otherwise exceptional ability to spur proliferation and activation of killer T cells directed at SARS-CoV-2. Their finding suggests that those hoping to avoid the manifold health risks associated with COVID-19 would do well to get vaccinated before they contract the disease.
The good news is that vaccination after having had COVID-19 does somewhat boost the numbers and battle-readiness of this SARS-CoV-2-infection-impaired killer T cell population — just not nearly as much as if vaccination had preceded infection.
Although the study didnʼt directly demonstrate it, killer T cellsʼlost punch after a bout of COVID-19 could spell a weakened immune response to a new SARS-CoV-2 assault later, boosting the odds that the virus will persist in overlooked infected cells and possibly contributing to the development of long COVID, suggested Mark Davis, PhD, professor of microbiology and immunology and a Howard Hughes Medical Institute investigator.
Davis, who is also the Burt and Marion Avery Family Professor, is the studyʼs senior author. Sharing lead authorship are postdoctoral scholars Vamsee Mallajosyula, PhD, and Fei Gao, PhD.
In contrast with antibodies, which are immune-generated proteins that can prevent a virus from getting inside our cells and kicking off infections, killer T cells roam through our bodiesʼtissues, inspect cellsʼsurfaces for telltale traces of infectious pathogens and kill infected cells.
A given killer T cell responds to only one of those telltale traces, or at most to a handful of them. In principle, it will attack only one type of pathogen.
While the bodyʼs gigantic repertoire of killer T cells typically contains numerous cells recognizing various features of that pathogen, the vast majority of cells in that massive repertoire remain at ease. For that reason, an infection by one particular virus wonʼt generate an exhaustive — and exhausting — immune response to every microbial invader under the sun.
