Exposure to cigarette smoke makes airway cells more vulnerable to infection with the new coronavirus, UCLA researchers found.
They obtained airway-lining cells from five individuals without COVID-19 and exposed some of the cells to cigarette smoke in test tubes.
Then they exposed all the cells to the coronavirus. Compared to cells not exposed to the smoke, smoke-exposed cells were two- or even three-times more likely to become infected with the virus, the researchers reported on Tuesday in Cell Stem Cell.
Analysis of individual airway cells showed the cigarette smoke reduced the immune response to the virus.
“If you think of the airways like the high walls that protect a castle, smoking cigarettes is like creating holes in these walls,” coauthor Brigitte Gomperts told Reuters.
“Smoking reduces the natural defenses and this allows the virus to enter and take over the cells.