The Centers for Disease Control and Prevention (CDC) estimated that during last year’s flu season, there were 47-82 million flu illnesses, 21-37 million flu-related medical visits, 610,000-1.3 million hospitalizations and 27,000-130,000 deaths as a result of Influenza (flu) cases in the United States (U.S.). That particular flu season, which was measured from October 2024 through May 2025, showed a spike in the spread of the flu across the U.S. in comparison to past years.

Currently, there are two main methods to get vaccinated for the flu: flu injection and the flu nasal spray. 

Ilse Larson, a professor of pediatrics at the University of California, San Francisco, explained the science behind how vaccines work. 

“All vaccines work by injecting or introducing something into the body that then relies upon the person’s immune system to create antibodies, and then those antibodies protect you from contracting whatever the disease is,” Larson said.

In this case, however, there are key functional differences between the nasal spray and injectable vaccine. 

 “The injectable forms of the flu vaccine are not live viruses, but they’re very close molecularly. It looks like the flu, so it tricks your body into thinking that it’s the flu,” Larson said. “The intranasal flu vaccine is a live virus, but it’s an inactivated virus, so you can kind of think about it as being a super wimpy or a weak form of the flu virus, but it is a live virus.”

Though the nasal spray (Flumist) is often viewed as being less effective than the injection, it does have beneficial qualities. A main reason people, especially children, favor the nasal spray is to avoid the traditional shot process altogether. 

 “Kids strongly prefer it and therefore many of their parents do,” Larson said. “It’s not very fun to bring a kid who’s scared and it’s hard as a parent to watch your kid be upset and to cry.”

Jenny Espionza-Marcus, the former chief physician and surgeon of California Correctional Health Care Services (CCHCS), also brought up the concern regarding the use of the nasal spray vaccine for patients who have any major contraindications, meaning they have some sort of condition or circumstance that suggests they should avoid using the drug.

“Patients just need to really be careful with the Flumist to make sure that they don’t have one of those major contraindications, including either being immunocompromised, having decreased or lower functioning immune system, being pregnant or even living with or having close contacts with people that are immunocompromised,” Espionza-Marcus said.

Another limitation of the nasal spray is that not everyone is able to get it: only people ages 5 to 49 are eligible.

“As a pediatrician, a lot of my patients aren’t eligible [for the nasal spray]. If you’re under age five, you can’t get it,” Larson said.  “And then if you have any sort of either immune system condition or condition with problems with your lungs, you will not be eligible for the nasal spray.”

Though there are downsides to both options, getting either one is a better option than no flu vaccine at all. 

“The main thing is that it’s important for people to get a flu shot, whichever one they prefer,” said Espionza-Marcus.

What you can do

As teenagers, getting the flu vaccine is not only vital to our own health, but is also necessary to protect the health of others in our community, such as elderly people or those who are immunocompromised. According to Families Fighting Flu,  getting vaccinated “contributes to the concept of ‘community immunity’ ”. This is the idea that when more people are vaccinated, there will be fewer cases of flu overall, which will ultimately protect the population who is more vulnerable. 

Not only that, but getting vaccinated also reduces the spread of the flu in schools, especially in high schools, where flu outbreaks can increase absences and therefore disrupt the learning environment. 

According to PubMed, “Influenza is a primary driver of school absenteeism for students; medically attended acute respiratory infection (ARI) due to influenza accounts for nearly 50 percent of school days missed due to ARI.” Missing school can lead to lower academic performance and more absenteeism overall can interfere with the student’s ability to learn productively.  

Ultimately, getting either flu vaccine, whether that’s the nasal spray or the injectable, will reap many benefits, not only for yourself, but for your community and school as well.