Influenza (the flu) is a highly contagious disease that kills over 36,000 Americans every year, including healthy children. The vaccine is recommended for all children and adults 6 months and older. It is especially important in people with chronic diseases such as asthma, in pregnant women, and in anyone caring for a newborn or young infant.
The disease
Influenza is a deadly disease that has been responsible for worldwide epidemics and the death of millions of people. Even now, it kills over 36,000 Americans, on average, every year. The virus spreads quickly and easily between infected people and can be spread through contact with surfaces such as door handles. Like many viral infections, it is far more common in the winter. The virus mutates (changes) every year and sometimes within a given season, making effective treatments and vaccines difficult to develop. The flu vaccine must be changed every year in order to be most effective. Like any viral disease, there is no cure. Nothing kills viruses once we are infected with them. There are some medications that slow the virus down, making the symptoms milder and allowing our immune system to eliminate the infection faster. There are also medications to provide relief from the symptoms (cough and cold medicines), but the only cure is time. Unfortunately, the virus or complications from the infection is a common cause of death, even in healthy children or healthy young adults, depending on the season and the particular strain of the virus that year. The best way to deal with this deadly infection is to prevent it in the first place.
The vaccine
As mentioned above, the virus changes every year, and the only vaccines we have right now are against the parts of the virus that change, so the vaccine has to be changed every year. Because the vaccine takes time to make, scientists have to predict what strains of the virus are most likely, months before the winter flu season. As a result, sometimes the vaccine is a good match for that year’s strains, and sometimes it is not. Even when it is not a good match, it usually provides some protection. Also, there is often more than one strain causing infection each year, and the vaccine may be a bad match for one but a good match for another.
The vaccine is now recommended for all children and adults 6 months and older. It is not just for high risk people anymore. The vaccine comes in two forms, an inactivated shot (IIV) and a live nasal spray (LAIV).
Dosing
Two doses are needed in children less than 9 years old, unless they have received 2 doses of flu vaccine in the past.
Otherwise, one dose is needed every flu season since the strains of the virus and the vaccine change every year.
Nasal flu vaccine
The nasal flu vaccine can be given instead of the injection (shot). It does give a person a mild form of flu infection and can only be used in some people. Children under 2 should not receive the nasal vaccine. Pregnant women and adults over 49 should also not receive the vaccine. Young children with a history of wheezing, older children with asthma, and children who have weakened immune systems or other chronic diseases may need to receive the injected vaccine instead.
Side effects
It is a common myth that the flu vaccine makes people sick, with runny nose and other flu-like symptoms. This is just not true. However, it can cause low grade fever, some soreness at the site, and sometimes general aches for feeling a little ill. These mild symptoms can be treated with ibuprofen. However, the flu vaccine does not cause runny nose, cough, vomiting, congestion, sore throat, or any other such symptoms.
The nasal flu vaccine, on the other hand, actually infects people with a mild form of the flu, and it can cause mild runny nose and flu-like symptoms for a few days. In the past, it seemed to be more effective at preventing the flu than the shot, probably because it does infect the person with a mild flu which results in a better immune response. However, in the most recent flu seasons, the shot was more effective than the nasal vaccine. Since the nasal flu vaccine causes a mild infection, it should not be given to children or adults with asthma or other respiratory problems.
There is a slight risk of a rare complication called Guillian-Barre syndrome, in which antibodies in the body attack nerves and cause weakness. There are many, many causes of Guillian-Barre syndrome. When caused by the flu vaccine, it is almost always mild and temporary.
Risks vs. benefits
Influenza is a deadly infection killing millions every year. It is highly contagious and very difficult to prevent, and like all viral infections, there is no cure other than time and our immune systems. Some medications can slow it down. The vaccine, though not perfect, is the best way we have to prevent this disease, and the benefits outweigh the risks.
Resources
Inactivated Flu Vaccine Information Statement (VIS) from the CDC
Live Intranasal Flu Vaccine Information Statement (VIS) from the CDC
References
Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2020-21 Influenza Season. MMWR; August 21, 2020;69(RR-8);1-24
Originally published October 15, 2008
Last updated: December 26, 2020