All of the COVID-19 vaccines authorized to date are delivered via intramuscular injection. But the intranasal vaccines that are now in development could lead to a more diverse vaccine landscape.
The company Altimmune (Gaithersburg, Md.) recently launched a Phase 1 clinical trial to test its single-dose adCOVID intranasal vaccine in 180 adult volunteers. Bharat Biotech (Hyderabad, India) is launching its own tests. In Europe, a newly-founded company known as Rokote Laboratories (Joensuu, Finland) is doing the same.
Intranasal vaccines could offer key advantages over intramuscular vaccines, said Dr. C. Buddy Creech, a professor within the Division of Pediatric Infectious Diseases at the Vanderbilt University School of Medicine.
First, an intranasal vaccine could trigger a broad immune response that includes both systemic immunity and local immunity in the respiratory tract. “Biologically, it makes sense,” Creech said. “We’d want to have a great deal of immunity at the actual site of where an infection starts.” For respiratory viruses such as COVID-19 typically first gain a foothold in the nose and in the throat. Generating mucosal immunity would be an advantage of the intranasal approval. And such a vaccine could also potentially offer strong protection against slightly different variations of the virus.
“There’s a lot of potential,” Creech said. But there are few examples of highly effective intranasal vaccines apart from the FluMist live attenuated influenza vaccine.
When asked whether an intranasal vaccine could reduce the need for mask-wearing in the long run, given its potential to stimulate mucosal immunity, Creech demurred.
In general, data related to COVID-19 vaccines’ impact on transmission are sparse. “It stands to reason that if you don’t get disease or high fever and if you you’re not sick for as long, you’re not going to spread as much virus,” Creech said.
Intranasal vaccines, however, could enable more people to get vaccinated, which in turn, could reduce the emergence of new variants. Ultimately, the quality and quantity of population immunity will be what enables society to relax COVID-19 mitigation measures. “The goal here is not to eradicate this virus necessarily,” Creech said. “The goal is to turn it into a common cold virus. And the way we do that is we generate a lot of immunity,” he added. “So I guess I bring that up to say it’s a tall order to require a vaccine to prevent transmission altogether — whether that vaccine is in the muscle or just under the skin or an intranasal vaccine.”
Filed Under: clinical trials, Drug Discovery, Drug Discovery and Development, Infectious Disease