Are nasal sprays the future of medicine? Here's what you need to know about using them for vaccines and lifesaving treatment.

Nasal sprays have long been a go-to savior for allergy sufferers, but lately there’s been an explosion of research into innovative ways that this user-friendly method could also be utilized to save lives and even deliver vaccines.

Are nasal sprays the medicine-delivery devices of the future? Here’s what experts say.

How nasal sprays are being used right now

Nasal sprays are already being used to treat or prevent a number of ailments, such as:

• Allergies: Seasonal-allergy-fighting nasal sprays may be the first thing a lot of people turn to, as sprays to help on this front are available in many forms, from steroids and antihistamines to decongestants and saline. They’re considered very effective and are preferred over oral medications by many allergists.

• Migraines: Earlier this year the Food and Drug Administration approved a new nasal spray treatment for migraines, which can relieve pain in as little as 15 minutes — faster than oral pain-relief options.

• Treatment-resistant depression: Esketamine, which is made from ketamine, has FDA approval in nasal spray form to help patients with treatment-resistant depression — referring to people who have tried at least two other antidepressants without remission or at least 50% improvement in mood. This approach is used under a doctor’s supervision in combination with a conventional antidepressant, with the hope of providing more rapid relief until the antidepressant kicks in.

• Opioid overdose: The first over-the-counter Narcan nasal spray became available in September and can save lives by reversing the effects of an opioid overdose, including accidental ones in children.

• Flu: A flu vaccine in nasal spray form was first approved by the FDA in 2003 and is available for people ages 2 to 49 who are not pregnant or immunocompromised.

How nasal sprays might be used in the future

And nasal sprays could have even more lifesaving applications in the future, including for:

• Intermittent rapid heartbeats: The American Heart Association recently said that a fast-acting nasal spray medication could someday allow patients with intermittent rapid heartbeats (which affect about 1 in 300 people in the U.S.) to treat themselves as soon as they develop symptoms — which would help them to avoid emergency room visits and medical interventions. In a new study, the nasal spray medication etripamil restored a normal heart rhythm in less than 30 minutes.

• COVID treatments: Some researchers are looking into the potential use of steroid nasal sprays as a treatment for COVID, with one study indicating that they could help prevent hospitalizations, intensive care unit admissions or death in people with mild to moderate COVID.

• Severe allergic reactions: A nasal spray to treat severe allergic reactions could become the first non-injection alternative to fast-acting treatments like EpiPen. The FDA recently declined to approve the treatment, nicknamed “Neffy,” after an advisory committee had recommended approval of the device, but the company behind Neffy plans to appeal the decision and resubmit an application in early 2024.

• More vaccine options: Some researchers have been looking into the use of nasal sprays for delivering COVID vaccines, though an Oxford-AstraZeneca device proved unsuccessful in an early-stage trial last year. Nasal COVID vaccines have already been approved in other countries, including Russia, China and India. And soon Americans might be able to give themselves flu vaccines from the comfort of their kitchen — with the FDA recently approving AstraZeneca’s application seeking approval for an at-home nasal spray flu vaccine; if authorized, that at-home vaccine could be available for self-administration in the U.S. during the 2024-2025 flu season.

The benefits of nasal sprays

Kristy Ainslie, a distinguished professor and chair with the University of North Carolina Eshelman School of Pharmacy, tells Yahoo Life there are advantages to delivering medication in nasal spray form.

“The first one is [that it’s] easy to apply. And your nose has a large surface area of the skin cells that are somewhat porous, and then there’s a lot of blood flow. So things that can go through get taken up and go very quickly into the blood,” she says.

Drugs taken in nasal spray form can also work a lot faster than they would if ingested orally; things like pills and syrups need to be metabolized first, which can slow down treatment.

“When you take something orally, it goes right to the liver and gets metabolized,” Ainslie explains. “In the nose, you don’t have that. You bypass this metabolism effect, which can make drugs that first go-around a little bit more potent than if you took them orally.”

Ainslie says there can also be benefits to delivering vaccines through the nose.

“When you have a vaccine injected into your muscle, it’s actually a very different immune response than when you’re giving something in your nose,” she explains. “When you have a vaccine that’s given through your nose [or] given orally, it can actually protect better in areas like the nose, the lung where you inhale a lot of these viruses, as opposed to something intramuscular.

“But it is harder to produce that effect,” Ainslie adds.

The challenges to using nasal sprays

Ainslie says nosebleeds are a possible side effect; and there are also barriers to using the nose for medication delivery. If a patient attempts to use a nasal spray treatment while they have allergic rhinitis (i.e., a runny nose), that thick mucus can make it difficult for the medication in a nasal spray to penetrate and be effective — which was one concern the FDA had about the EpiPen-alternative Neffy. And if you blow your nose, you could also end up expelling the treatment.

“Think about if you put a drug up there and then you blow your nose. Where’s the drug? It’s on your tissue. And so that’s one disadvantage,” Ainslie says.

Several studies have also indicated that a nasal spray flu vaccine is less effective than the traditional flu shot. Donna Farber, a professor of immunology and microbiology at Columbia’s Vagelos College of Physicians and Surgeons, tells Yahoo Life she’s intrigued but skeptical of using nasal sprays for vaccine delivery.

“It’s theoretically a really good idea, but there’s potential issues with it,” she says.

“When you introduce a vaccine, that vaccine has to go to a local lymphoid organ like a lymph node, which are all over our bodies. And in the lymph node is where that response will be initiated,” she explains. “When we put it in the arm, we know there’s a lot of lymph nodes near the injection site. But when you’re putting it up the nose, it’s not entirely clear. Is there really lymphoid tissue around where you’re going to mount a really good response? So I think that’s a potential limitation.”

What’s next?

While Farber and Ainslie say nasal sprays have lots of antiviral potential, Farber believes more research needs to be done before nasal vaccines can become a reliable option. So while the nose might be a good route for things like respiratory tract infections, we’re unlikely to see routine childhood vaccines available in nasal spray form anytime soon.

One nasal vaccine idea that Farber believes has potential would be to use nasal sprays as a kind of booster, following a vaccination with a conventional jab in the arm. This concept, which is known as a “prime-pull” strategy and has shown early promise in mice studies, involves “priming” the immune response with a shot in the arm and later “pulling” the immune cells to the site in need of defense (i.e., the nose) with a nasal spray booster.

Ainslie says one of the things that makes nasal spray options so exciting is the ease of delivery — which can be a lifesaver in an emergency like an opioid overdose or an allergic reaction.

“I think that’s one thing that intranasal delivery affords, is [that for] a lay person, it’s very straightforward,” she says.