In a breakthrough in the battle against influenza, researchers have developed a way of classifying host immunity, which could lead to individualised vaccine regimes to give at-risk patients long lasting immunity.
While it has been well established that the effectiveness of influenza vaccines can vary considerably between people — depending on vaccine types and individual circumstances — immunisation programs use a regular vaccine schedule that largely ignores the contribution of host immunity.
The flu causes about 650,000 deaths each year and serious illness for up to 5 million people worldwide, and the team said their discovery will not only reduce influenza-related illness, but also reduce the logistical and financial impacts on healthcare systems.
Over the course of four flu seasons, the researchers took blood samples from 286 healthy donors aged 18-81, 45% of whom were women, to try and identify those who were still unprotected after vaccination.
The results of the study were presented by Dr Nhan Nguyen, a postdoctoral researcher at the Centre for Individualised Infection Medicine, at the annual conference of the European Society of Human Genetics, in Hannover, Germany on June 4.
“Each seasonal influenza vaccine is designed to protect against three or four different flu viruses, so a lot of factors are involved in an individual’s vaccine response,” Dr Nguyen said.
“For example, as the influenza vaccine is updated every year in response to variations in the virus, this means that the pre-vaccination antibody level can differ in individuals due to previous infection or their vaccination history.
“As such, we aimed to identify the robust signals of response that spanned across different influenza seasons and were consistent despite the variations in the response of the same individual to different flu viruses.”
After examining participants’ pre- and post-vaccination antibody status, Dr Nguyen and his colleagues used multiomics1 technology to identify proteins and metabolites that could serve as predictive markers for the identification of individuals who had low levels of protection even after vaccination.
The results from the new method were consistent throughout the four flu seasons and across four different vaccine updates that occurred during this time.
“This is a more sophisticated way of identifying such people than that which is used at present, where protection is assessed solely by changes in the number of antibodies in the blood pre- and post-vaccination,” Dr Nguyen explained.
“The current vaccine response calculation may therefore not provide host-specific information that is sufficiently accurate to estimate a person’s immune response and/or vulnerability to future infections, since some people already have high antibody levels at pre-vaccination that do not change significantly after they have received a vaccine.”
Dr Nguyen’s team hope that the newly identified biomarkers will reduce the cost of vaccine response screening and enable the development of personalised influenza vaccine administrations for vulnerable people — including higher doses, repeated vaccinations, or the addition of an adjuvant to boost response.