For years, nasal sprays have helped people with allergies. 

Now, they’ve been used to treat migraines, depression and opioid overdoses. There's even an intranasal option for the flu vaccine.

Doctors and researchers say they’re working on other vaccines that would be beneficial in nasal spray form.

"Mucosal immunization gives you superior immunity in the airways, which is of a special utility for respiratory diseases, like covid,” radiation oncologist Dr. David T. Curiel with the Washington University School of Medicine in St. Louis said.

Dr. Curiel says vaccines in nasal form target the airway, where a respiratory virus enters the body.

“A systemic injection, like MRNA, will augment antibodies in the blood, not so much in the lung. Airway vaccination — nasal vaccination — augments antibodies in the nose and airways, and that's a better defense,”Curiel said.

People who suffer from severe allergic reactions could also soon have a new defense. According to the Allergy and Asthma Network, ARS Pharmaceuticals completed a clinical study for a nasal pray version of epinephrine called "Neffy" that just got FDA approval.

The FDA also recently approved a self-administered FluMist nasal spray vaccine that could be available later this year.   

Flumist is approved for the prevention of influenza disease caused by influenza virus subtypes a and b in individuals 2 through 49 years of age.

Oother clinical trials of nasal sprays include Alzheimer's at the University of Texas medical branch and abnormal heart rhythms at Weill Cornell Medicine in New York.

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