Researchers say they've pinpointed a gene that affects how much protection the flu vaccine gives a person.
They analyzed blood samples from more than 200 people who'd had organ transplants. The researchers found that versions of a gene called IL-28B influenced the strength of the immune response trigged by the flu vaccine.
Each person has two copies of this gene. The T version of the gene is more common, while the G version is less common. Of the people in the study, most had two copies of the T version. Some people had one copy of the T version and one copy of the G version. A few had two copies of the G version, according to the researchers.
The blood of people with at least one copy of the G version of the gene were more likely to have detectable antibodies against the flu strain targeted by the seasonal flu vaccine, according to Adrian Egli, University of Basel in Switzerland, and colleagues.
The researchers then replicated their findings in almost 50 healthy volunteers. They had a similar response, though the effect was more pronounced in transplant patients, according to the study authors.
They said their findings show that IL-28B plays an important role in the immune system's response to flu vaccination. That means it could offer a target to boost the effectiveness of seasonal flu vaccines, they said.
The study was published Dec. 11 in the journal PLoS Pathogens.