Anti-flu vaccination: let's go!

The treadmills scroll and the pipettes tumble, caught by robotic arms, scrutinized from every angle. At the Sanofi plant in Val-de-Reuil (Eure), the production of influenza vaccines is being finalized. The pharmaceutical company manufactures 200 million doses every year at 5 sites, which it distributes in 125 countries.

»READ ALSO – Vaccination against influenza: all our articles

And it's every year "a race against the clock," says Philippe Ivanes, director of the production site. Because the flu vaccine follows a complex path. If the "basic" recipe is always the same from one year to the next (and therefore does not require a new marketing authorization), the virus strains that compose it are chosen each year by the Organization. World Health Organization in February for the next winter vaccine in the northern hemisphere. The manufacturers then have only a few months to manufacture their seeds from the supplied strains, incubate them on eggs, purify the antigens obtained, carry out the final mixture, distribute them in syringes (and multi-dose vials for some countries), condition and, finally, send them all over the world.

This year, we are told in the pharmaceutical laboratory, the race was all the faster as the WHO was slow to choose one of the four strains making up the vaccine. A crucial step. Because unlike others, like measles, the flu virus has a changing soul … Every year, it changes. Generally a little (surface proteins, those that our antibodies will learn to recognize and that are present in the vaccine, vary) and, sometimes, fortunately less often, much (we speak of "antigen cascade", when two viruses of the The same type is found in a host, often an animal, and recombines to form a totally new virus that our immune systems will be unable to recognize).

And every year, it's the same puzzle for the public authorities. How can the population be vaccinated more? WHO has established that 75% of populations at risk of severe influenza should be vaccinated to control the epidemic and effectively protect non-vaccinated people. But if these rates were almost reached among people over 65 until 2009, they have since dizzily dropped: at the end of December 2017, barely 53% were vaccinated; and 31% only in those under 65 but at risk of serious influenza …

However, the disease is devastating every year: last winter, in eight weeks of epidemic, it will have resulted in 1.8 million medical consultations, 65,600 emergency room visits, 11,000 hospitalizations including nearly 1,900 in intensive care units , and has been involved in 9,900 deaths, mostly seniors. Influenza is generally benign in a healthy adult (at the cost, however, of an immense fatigue that can last several weeks), but in a patient weakened by age or a chronic pathology, "the virus will arrive and give a big kick in the cardiovascular and respiratory systems"Says the D^r Jacques Gaillat, infectiologist at the CH Annecy-Genevois and come to preach the good word to journalists visiting the plant of Val-de-Reuil.

In fact, the specialists insist, despite a not always fantastic efficiency, influenza vaccination is the only weapon we have to limit infections and, if the infection still occurs, reduce the severity of the disease. A study published in the journal Clinical Infectious Diseases in February 2019 calculated that in the United States, for the 2017-2018 season, the vaccine, with an efficiency of only 38%, had prevented 7.1 million cases. , 109,000 hospitalizations and 8,000 deaths.

Vaccination in pharmacy, new weapon

In France, the government has this year a new weapon that can give hope for better immunization coverage: tested last year in four regions, vaccination in pharmacies is extended to the whole of France (in addition to the vaccination by doctors, midwives and nurses). Volunteer pharmacists, provided they have followed a dedicated training and have an isolated room, can vaccinate all those concerned by the recommendations. But if the operation is a success, then maybe it will be necessary to manage … the shortage of vaccines! "Pre-orders made by pharmacies increased by 10 to 15%, and we took an extra margin of safety", Says Sanofi.

Out of these specific recommendations living people at risk, "from 6 months, everyone can be vaccinated against influenza," says Vincent Enouf, deputy director of the national reference center for influenza at the Pasteur Institute. And health workers must do more, he pleads: "They are not enough vaccinated even in services that receive patients fragile!"