Researchers discover that individual flu strains elicit an antibody response to multiple different flu strains already experienced by a patient
A global team of researchers using a new modelling system have discovered that upon infection, patients exhibit immune responses to every strain that the individual has encountered, not just the infecting strain. The strongest responses came from the strains most closely associated with the infecting strain, but nonetheless a response was recorded to all previously experiences strains. This phenomenon has been dubbed ‘back-boost’ by the researchers.
The protocol through which current seasonal flu vaccines are decided focuses on flu strains circulating in February when the WHO meets to select a strain. By the time a few hundred million vaccines have been manufactured, and the new flu season rolls around, circulating flu strains are likely to have evolved away from the strain in the vaccine. This research suggests that we could improve the effectiveness of vaccines by predicting how we think the current strains will evolve during the 8 months or so before the vaccines hit the market.
This research shows that the WHO would not need to be 100% accurate in their predictions as a vaccine that is remotely close to the circulating strain will still promote a strong immune response to the circulating strain. The real beauty of this approach would be that the ‘Back-boost’ phenomenon provides a safety net that would provide coverage of current flu strians, and even flu strains that appear contrary to predictions.
One of the primary authors, Dr. Sam Wilks of the University of Cambridge and the WHO Collaboration Centre for Modelling, explains that “faced with uncertainty about how and when the flu virus might evolve, it’s better to gamble than to be conservative: if you update early, you still stimulate protection against current strains — much worse is if you update too late. Rather than trying to play ‘catch-up’, it’s better to anticipate and prepare for the likely next step of influenza evolution — and there is no penalty for doing it too soon.”
Cambridge’s Professor Derek Smith adds that “the beauty of this approach is that it would not require any change to the current manufacturing process. From the point that the new strain has been selected through to an individual receiving their shot, the steps will be exactly the same. The only difference would be greater protection for the recipient.”
you can find the study here: Antibody landscapes after influenza virus infection or vaccination