Inhaled Vaccines May Be The Future
Intramuscular injections are not necessarily the best way to deliver vaccines, they are just the most common way. Pharmaceutical companies may choose them as the first batch of candidate vaccines because they are a proven method of delivering antigens and triggering the production of small molecules for immune system antibodies, and speed is of the essence.
But injections are not the easiest way to get vaccination for everyone. They usually have to be refrigerated or frozen, which limits the scope of distribution. They require syringes, which are a limited resource, and require medical professionals to extract them from vials and transport them to the arms.
Currently, even inhaled flu vaccines need to be injected in the health care provider's office. But in theory, the inhaled vaccine can be administered by the recipient himself, which will alleviate the bottleneck of the syringe supply chain. "You could use it like an inhaler, or like Flonase," an inhaled allergy medicine people can quickly sniff, says Renata Pasqualini, an oncologist at Rutgers University and chief science officer at Phage Novo Bio. "That's the future."
Inhaled vaccines can be provided to people who do not need to see a doctor. "Think about a vaccine you could mail out to people," says Pasqualini. "People who are homebound or otherwise unable to access clinics could easily gain immunity. It could also be a faster way to distribute booster shots, should we need them."
Inhaled vaccines may even work better, too. Pasqualini's animal research on Phage Novo vaccine shows that inhaled vaccines produce a stronger immune response than injected vaccines. The reason is not clear, but it may be related to the route of exposure: by directly entering the lungs, the antigen has the opportunity to trigger elements of the immune system in the airway. The antibodies produced by this part of the immune system are slightly different from blood. For mainly respiratory viruses, targeting the mucosal immune system can improve overall immunity-although more research needs to be done to confirm whether this is the case.
So far, all inhaled Covid-19 vaccine candidates are either in animal trials or in the first phase of clinical trials to test the safety of these sprays in a very small number of healthy people. Generally, it may take several years for a vaccine to go from early clinical trials to market. Currently, drug regulatory agencies speed up the authorization process by listing the exact types of data that companies need to generate to prove that their products are safe and effective. The urgency of vaccinating the world may maintain these high-speed processes in order to get these vaccinations into the noses of people all over the world.