We are getting closer to the possibility of creating a universal vaccine against all (or almost all) the possible forms of influenza, without the need to “chase” the variants of the virus every year. This announcement, which was made in the pages of the journal Nature Communications, comes from researchers from the Perelman School of Medicine of the University of Pennsylvania (one of the most prestigious and ancient faculties of medicine in the United States), who carried out experiments and achieved excellent results on laboratory animals with a type of vaccine that is completely different from those currently on the market (and that often have limited effectiveness).

“Traditional” vaccines are synthesized as soon as the initial signs of the flu virus appear, usually in spring, in the southern hemisphere. Based on estimations and indications from all countries all over the world, the health authorities – and first and foremost the World Health Organization – identify the strains that most probably will be responsible for the epidemic in the next cold season, and give instructions so that the specific formulations of the vaccine can be prepared. However, predictions are not always right, and in any case the strains change from year to year, meaning that the vaccines have to be continually reformulated.

The researchers from the University of Pennsylvania, on the other hand, have switched strategy, focusing on a possible “target” hardly used to date: a particular area on the external surface of the virus called the hemagglutinin stalk, which – it has been discovered – appears to be practically the same in all variants of the virus (and therefore can bring about a long-lasting and wide-ranging immune reaction). However, this is not enough. In order to achieve the best result possible, the American researchers then applied a highly-sophisticated and innovative technique: what they did was insert a laboratory-modified copy of the genetic code of the virus (mRna) directly into the virus, which is used by the latter to produce the molecules of the hemagglutinin stalk.

Hence, due to a series of very complex mechanisms, the contact between these traits of the genetic code of the virus and the immune system strongly enhanced the response of the defence system of laboratory animals against the virus (because the genetic code of the virus, enclosed by immune cells called dendritic cells, produced the molecules of the hemagglutinin stalk directly inside these cells, making them much more “sensitive” than those in traditional vaccines).

The studies will now continue and tests will be carried out on monkeys, and then on humans, with the hope that we will finally have a vaccine to be administered at the very most only several times in a lifetime (a bit like the tetanus jab), and that will contribute to reducing the number of deaths linked to influenza, which still stands at several hundreds of thousands each year worldwide.