In some cases of flu, the immune defenses worsen the patient’s state of health by trying to fight the virus.
Nearly 10,000 people in France died from the flu during the winter of 2018-2019. The viral infection is particularly dangerous for the most fragile such as pregnant women or the elderly. Researchers at the University of Minnesota’s School of Medicine in the United States looked at the reactions of the immune system in the event of influenza. They find that they can sometimes be harmful to the body. Their findings are published in the journal PLOS Pathogens.
C lymphocytes, defenders of the body
“One of the reasons why people get sick during the flu, or even that some die, is not the development of the virus itself, explains Ryan Langlois, author of the study, but it is because mechanisms put in place by the immune system to control the virus.” Researchers have deciphered the action of immune defenses in the event of influenza. In a healthy person, the virus is eliminated by the body within a fortnight thanks to the action of T lymphocytes.
Infected cells evade the immune system
In this research, the scientists focused on infected cells that survive in the body despite the action of T lymphocytes. Previously infected cells are able to act quickly to eliminate traces of the virus, however, T lymphocytes can only eliminate cells if the virus remains “visible”. Thus, some cells escape the immune system and are able to divide and then multiply. “This study provides us with evidence that preventing immunopathology is important,” concludes Ryan Langlois. Immunopathology specifically designates this harmful action of the immune system on health.
The vaccine is available for 2019/2020
In France, the vaccination campaign against the seasonal flu started on October 15. From now on, patients can be vaccinated directly at the pharmacy. Health authorities recommend that certain people get vaccinated, including pregnant women, people over 65, children with chronic illnesses (diabetes or asthma) or people with HIV. The vaccination campaign should last until January 31, 2020.
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