A key component of modern medicine, which has made the flu so much less deadly now than in the past, is herd immunity. Of course, the average young and healthy person probably has little concern of developing a dangerous side effect of the flu, but the benefits of herd immunity is not even directed at the young and healthy: it is for the more susceptible among us — the pregnant, the very young, the elderly and the immunocompromised. For these people, immunization is crucial, but only if the vast majority of the population is taking part.
The importance of getting the flu shot is compounded by the fact that babies under six months and the severely immunocompromised are unable to get the shot, as it would not vaccinate them, but simply make them ill. They are also at higher risk of deadly side effects, like pneumonia.
Though some immunosuppressed people are well enough or functioning enough to vaccinate, many older people, for example, are more susceptible to the flu virus due to weaker immune systems. A study in England and Wales determined that vaccinating young people was a more viable strategy in flu prevention in the elderly than vaccinating the elderly themselves. This is because immunization is contingent on immune cell response to a deactivated form of the virus, which, when unsuccessful, renders the shot less effective.
For the pregnant, the flu shot is essential: influenza causes fever, which can permanently damage a fetus. Consequently, the mother is also apt to become more sickly when infected while pregnant.
Herd immunity helps these immunosuppressed and immunocompromised groups especially because, once a certain threshold of vaccinations is achieved, it is not nearly as worrisome that the very old and very young are not vaccinated, as the virus will not spread with the same capability.
This would require vaccination of around 80 to 90 percent of the population, depending on the effectiveness of the shot in that year. In the 2016-2017 flu season, the states with the highest vaccination rates still only measured 50.8 to 55.4 percent vaccinated, which is not nearly enough for herd immunity to function.
But hundreds of thousands of people saw hospitals during flu season, and thousands more have died from influenza. This is a reality.
This is not about the vast majority of Americans who will survive the 2017-2018 flu season and subsequent seasons; it is for those who have no decision in whether they get ill or not.