BALTIMORE — A new study from Johns Hopkins Medicine shows people who either were infected with the original COVID-19 virus or vaccinated, likely maintain some protection against the omicron variant.
Researchers describe how portions of a protein in the original virus trigger a response by what are known as killer T cells in the human immune system.
They concluded that the T cell response to omicron "should be virtually as strong as it was to the initial form of [COVID-19].”
The T cells used in this latest study were from blood samples collected in 2020 from 30 patients who had recovered from mild to moderate cases of COVID-19.
Blood samples used in the study were taken from 26 to 62 days after the donors stopped having COVID-19 symptoms, enabling their T cells to ramp up.
The researchers caution that their finding only relates to one type of cell-mediated immunity — the body’s defense against invaders that doesn’t involve circulating antibodies — and that it may be what is known as humoral immunity that fails when omicron causes so-called breakthrough infections.
Either way, the writers say more research is needed to fully define why people who have this protection may still get sick from omicron.
The full study can be read here.