Today, the vaccine is injected into the muscle, but it is not 100% effective.
The flu epidemic has just ended and it has killed more than 7,000 people. The best way to protect yourself is to get vaccinated. The product is never 100% effective, but researchers at Inserm Unit 1135 show that a change in the mode of administration can improve its effectiveness. The study was led by Behazine Combadière and the results were published in the JCI journal.
When you get vaccinated against the flu, the product is injected by the muscular route. It allows the body to produce antibodies (humoral response). The new technique developed by French researchers causes a cytotoxic response: the vaccine stimulates the production of T cells, white blood cells capable of destroying infected cells. This new route of administration uses either intradermal injection or transcutaneous application, that is to say by the hair follicles.
Important results for the elderly
60 people aged 18 to 45 years participated in the clinical trial, conducted in collaboration with the CIC of vaccinology led by Dr. Odile Launay. Some of them had the expected cytotoxic response. "This result argues in favor of considering this route of injection of the vaccine insofar as it triggers an additional immune response to that obtained in the context of a conventional vaccination," explains the director of research, Behazine Combadière. Cytotoxic responses would be especially protective in the elderly after influenza vaccination. "
The day after the vaccination, the researchers studied, thanks to a genetic analysis of the blood, the immune response. Since they used three routes of administration, they expected to find three signatures of immunity. "Our results show only two signatures," says Behazine Combadière, "and these two signatures are correlated with the immune response of the individual: those who respond to the vaccine by increasing their humoral response and those who respond by inducing a cytotoxic response." Some biomarkers would even know the quality of the immune response in the body three weeks later. Further trials should be done before hoping to apply this technique during vaccination campaigns.
The vaccine for next winter already unveiled
Every year, the World Health Organization decides on the composition of the next vaccine largely before the outbreak begins. It establishes probabilities on the activity of different strains of influenza viruses before transmitting it to manufacturers, who need several months to develop it. For the northern hemisphere, the composition of the vaccine for next winter was published last February.