Health. Seasonal Flu: How Vaccines Work

The National Institutes of Health and Medical Research (INSERM) describes the influenza vaccine as “made up of inactivated viral cells” on its website.

These viral cells have no genetic material, which usually allows them to infect and multiply with a single cell.

Therefore, “the vaccine does not give the flu under any circumstances”, Inserm recalled.

Permanent renewal

However, influenza is unique in that it is caused by a wide variety of viruses that develop rapidly.

Therefore, “the strains of influenza virus in circulation are not the same year after year. That is why the flu vaccine must be renewed every year, ”explains Health Insurance.

According to the Vaccination Info Service, a site maintained by the French Agency for Public Health, three vaccines were used in the 2021-2022 vaccine campaign.

Each of them “was developed to protect against four strains of the influenza virus”, health insurance details.

The MSD Medical Manual concludes that vaccines “reduce the rate of infection by 70 to 90% in healthy adults” when compared to species that cause seasonal infections.