Current smokers may be at risk for lower immune responses to some COVID-19 vaccines, Japanese researchers say, though more research is needed before firm conclusions can be drawn.
In a preliminary study of 378 healthcare workers, ages 32 to 54, the researchers analyzed levels of protective antibodies induced by the mRNA vaccine from Pfizer and BioNTech, using blood samples obtained roughly three months after the second dose. As has been found in previous studies, older participants had lower antibody levels.
After taking age into account, the only risk factors for lower antibody levels were being male and smoking – and the gender difference might be because smoking rates were twice as high in men as in women, the researchers speculate.
In a paper posted on Saturday on medRxiv ahead of peer review, they report that antibody levels were higher in former smokers than in current smokers, which “suggests smoking cessation will reduce the risk of a lower antibody titer.”
Microscopic lung damage may continue in ‘long COVID’
The persistent breathing issues that plague some COVID-19 survivors, known as “long COVID,” may be due to microscopic processes that continue to damage lungs even after the acute infection is over, new research suggests.
The researchers studied blood and airway cells from 38 patients who still had breathing problems at least three months after they were discharged from hospital. Compared to healthy volunteers, the airways of these COVID-19 survivors had higher numbers of immune cells that defend against viruses but can also cause damage.
They also had higher levels of proteins that are present when cell death and tissue repair are happening.
The findings, which still need confirmation in larger studies, suggest some patients have ongoing disturbances in their immune cells and damage to cells that line the airways, even several months after their initial infection and discharge from hospital, said James Harker of Imperial College London, coauthor of a report published on medRxiv ahead of peer review. “In a small group of patients, we were able to show that the abnormalities may in fact resolve with more time,” Harker said.