Nasal vaccine devices have the potential to offer more convenient and more effective protection against a variety of viruses.
In 2024, the FDA approved a nasal spray as the first at-home influenza vaccination, allowing adults to vaccinate themselves or someone in their care without a needle jab or a trip to the pharmacy.
Intranasal vaccines are in development for RSV, HPV, norovirus, hepatitis B and avian flu. A nasal drop vaccination for Covid-19 is already approved an in use in India, and researchers are evaluating whether a nasal spray might be a more effective method of preventing Covid infections than those drops or the intramuscular injections that are approved in the U.S.
There have also been promising developments with antibodies or peptides delivered via nasal sprays to protect people from infections or to treat them.
To learn more about nasal vaccine devices and how they’re designed, we spoke with Aptar Pharma VP of Scientific Affairs Julie Suman, who’s been working in the nasal space for more than 20 years.
The Covid-19 pandemic “jump-started the need to consider multiple routes of vaccinations [for] multiple shots on goal,” Suman said. “We are excited about the opportunities for intranasal vaccination.”
Why is there so much more attention now on nasal vaccine devices?
Suman: “One of the reasons why nasal became so attractive is the concept of mucosal immunity that would potentially limit the the spread of the virus. So not only could you develop the ability to fight the infection yourself, you would not necessarily be shedding the virus and infecting others. In addition, with Covid it’s generally thought that the virus deposits in the nose and interacts with those ACE receptors and then will translocate to the lungs, so if we can stop it in the nasal cavity the person would have a better outcome, preventing that disease from evolving into a full-blown infection.”
What exactly is mucosal immunity?
Suman:
“There’s two mechanisms of immunity. Systemic is when you get your shots, it’s circulating in the bloodstream, and different type of antibodies will fight the virus. The nose will generate a different type of antibody that’s sitting around waiting to to interact: an IgA (immunoglobulin A) antibody, versus IgG (Immunoglobulin G) when you get a systemic immunization. Different types of antibodies get generated from those routes of administration, and it’s thought that IgA — mucosal — is key for preventing the spread of infection. … There is significant immune tissue in the nasal cavity that can induce that immune response, so it has the opportunity to be used for for more than than respiratory viruses.”
How do sprays activate that response?
Suman: “Generally, the spray will deposit in the nasal cavity and interact with the lymphoid tissue in the back of the nasal cavity called the NALT: the nasal-associated lymphoid tissue. There are also dendritic cells in the nasal epithelium that allow the vaccine to interact. The dendritic cells are throughout the nasal cavity and the NALT’s in the back. When we administer our sprays, we want to target those regions in the nasal cavity.”
Do you need to design nasal vaccine devices specifically to hit those targets?
Suman: “We want to make sure we’re controlling the droplet size and the the shape of the spray, if you will. How the person uses it can also play a role, depending on how the device operates. But generally, you want to aim the device in that target region. What we don’t want to do is aim the vaccine toward the roof of the nasal cavity. There was a case maybe 15 years ago where a component of a nasal vaccine entered the brain through the olfactory region and caused some unwanted side effects. And so the general school of thought is we don’t want to really hit that region of the nose with a vaccine.”
Does droplet size matter, and can you control that?
Suman:
“The size of the droplets will determine whether they would deposit in the nose or the lung. If you want to deposit droplets in the lung, they have to be smaller than 5 microns. In the nose, the droplets are generally larger than that. … In the orifice of the device, there are mechanisms for generating the droplet size so the device itself will work with the fluid to produce the different sizes of droplets. That’s a very important part of our design process and control process to make sure that we’re delivering appropriate and reproducible droplet sizes.”
Are there pediatric design considerations?
Suman: “We want to make sure that it’s comfortable for a child to use, because their noses are smaller, and some of the devices you’ll see are indicated for children and even neonates. … It depends on the shape of the nozzle itself. And an adult is going to be upright when getting a vaccine, but that might not be the case with a child. You might be cradling them. So we’ll look at things like how the orientation of your head or the child’s head may affect where the product would distribute in the nose.”
What’s the advantage of sprays versus droppers for nasal vaccines?
Suman:
“I’m not sure that a dropper will work with Western regulations, because it’s a little more challenging to monitor the dose or control the dose with a dropper, compared to sprays that are metered so we know we’re giving a very specific volume — which equates to the dose — when we spray it. Droppers are certainly a more cost-positive solution for developing countries, but I don’t know that we’d see droppers in the in the Western world.”
Besides safety and efficacy, what sort of regulatory considerations are there for nasal drug delivery devices?
Suman: “There are guidelines on human factors. Can the person or the medical practitioner understand how to use the device? Can they use it correctly? We have a company in our portfolio called Noble that does human factors studies and helps produce instructions for use that our pharma companies can incorporate into their packaging and labeling. There’s requirements around the materials and biocompatibility. These devices are injection molded, so there’s criterion around quality. … There are also FDA guidelines for quality control tests they want to see. We look at the shape of the spray, the size of the droplets. Certainly, dose reproducibility is No. 1. Compatibility of the formulation with the device itself is also important.”
How are nasal delivery devices sterilized?
Suman: “Everybody has a different process to sterilize a device. Some people use steam, some use gamma radiation when we when we throw in a biologic or vaccine, that becomes trickier, because the sterilization process can damage the molecule itself and maybe render it ineffective. The interesting thing about nasal is that from a regulatory standpoint, there is no FDA guidance that says a nasal spray must be sterile. So there’s not an obligation. However, customers may want for various reasons to have a sterile product. … Anybody who’s in this space is probably having that conversation with their pharma [customer].”