Just as some patients respond better to chemotherapy than others, the effect of a vaccine can vary in some individuals. With cancer treatments, genes are the major factor but for vaccines previous infection and vaccination history also play a role.
Could the ultimate destination be a simple blood test that helps doctors decide which vaccine – and which delivery method – is best suited to their patient?
Many still see this as science fiction. Others say that even if this were to become technically possible, it would prove impractical for logistical and cost reasons.
Dr Béhazine Combadière, Director of Research at INSERM at the Sorbonne in Paris, is an optimist. She’s careful not to promise that personalised vaccines are just around the corner, but she refuses to limit her thinking.
“Two years ago I would have said it was not possible [to contemplate personalised vaccines] but we have seen several developments in our understanding of vaccination and I think we need to be creative in our approach to research,” she told Vaccines Today after speaking at a lecture organised by the European Voice newspaper and sponsored by Pfizer.
Dr Combadière said significant improvements have been made in scientists’ understanding of how different types of vaccines affect the immune system. In addition, the decision to deliver vaccines using, for example, a needle or patch can influence how they work in individuals.
Add to that the ever-deepening knowledge of how different elements of the immune system “cooperate”, plus the impact of previous immune system “experience”, and the scope for new approaches to immunisation becomes clearer.
One illustration of the complexity of the immune response, says the Sorbonne researcher, was seen during the 2009 influenza pandemic.
Older people who had been infected with H1N1 influenza in the 1970s had a different response to the disease and to vaccines during the pandemic in 2009 compared to younger people who had never encountered a virus like this one.
The immune systems of those who had either been infected or vaccinated during the 1970s had changed permanently and their system ‘remembered’ it three decades later.
Similarly, people who have had annual seasonal flu vaccines have a different immune experience to those who have never been vaccinated. All of these factors should be explored and could eventually be taken into account when doctors are recommending vaccination.
However, Dr Combadière said much more research is needed in several areas. “We know there is great heterogeneity in the normal adult healthy population – not to mention very young or very old people. Some people are low responders and some are high responders. And we don’t know why.”