A team of researchers from the Fred Hutch Cancer Center and the University of Washington has determined how person-to-person variation in antibody immunity plays a key role in shaping which influenza (flu) strains dominate in a population. The study findings were published as a Reviewed Preprint in the scientific journal eLife.

The team developed 78 genetically marked flu viruses that represent circulating strains and vaccine variants.

Analyzing blood serum samples from 150 children and adults, the researchers obtained more than 11,000 measurements of the immune response. The results showed significant differences between individuals: some children showed strong neutralization of most strains, while others had a weak immune response.

Comparing the immunity data with the dynamics of the spread of strains in the 2023/24 season, the researchers discovered an important pattern. The most successful were the viral variants against which a significant part of the population had a weak immune response.

The main factor is not the average immunity of the population, but individual variations in protection, explained the study's co-author, Dr. Andrea Loes.

The results are important for predicting the evolution of the flu virus and developing effective vaccines against it.

Traditional methods using pooled blood serum samples can miss important features of the immune response.

These results could change the approach to epidemiological forecasting and the development of preventive drugs.