RECENT STUDIES SHOW THAT A NASAL SPRAY is more effective in protecting mice against influenza than vaccines injected into the muscle. This is the finding of the Yale School of Medicine research team led by Akiko Iwasaki, Ph.D.
I faithfully get a flu shot annually. The jab is into my upper arm muscle. The intramuscular way is how we’ve done it for four decades. But for respiratory infections, is there a better means of administering a vaccine?
Imagine a world where a spray into your nose will complement the existing vaccines against diseases such as COVID-19. Those fearful of the jab might be more open to having a nasal vaccine that is a spray. Let’s look at this innovative approach to vaccination for respiratory diseases.
Before we get to her findings, here’s a bit about the remarkable woman leading the research team. Dr. Akiko Iwasaki received her doctoral degree from the University of Toronto (Canada) in 1998. She did her postdoctoral training at the National Institutes of Health (USA) before joining Yale as a faculty member in 2000.
But her story goes beyond her innovative research investigations. In her 2019 piece in Nature Immunology, she recognizes the importance of diversity in the highest levels of the immunology research community.
Dr. Iwasaki also focuses on barriers faced by women and minority scientists, including grant review bias, unusually high demands on their time, work that is not rewarded, and the many ways diversity has benefited her lab over the past two decades.
You can find her advocating for women scientists (and other underrepresented minorities) on Twitter. You’ll learn a lot about viruses such as COVID-19.
Mucosal vaccines: Putting the guard outside the door
The Yale team discovered that spraying the inner nose lining (mucosa) with a vaccine yields a more robust immune response when compared with jabs into muscles.
When comparing various routes for vaccine administration, Dr. Iwasaki and colleagues noted that after the nasal route vaccination, the immune system secreted substances known as immunoglobulin A (IgA) into the mucosa.
The IgA coats the mucosa and protects the host by preventing the virus from entering the body. She puts it this way: “It’s like putting the guard outside of the door instead of inside the door where antibodies typically work, inside the body.”
In a recent Yale School of Medicine Journal article, the lead researcher continues:
“There are two compartments of the immune system. The first is the systemic circular one where T-cells, B-cells, and antibodies circulate and survey for infection. There is a different compartment, the mucosal compartment where you can immunize and induce immune responses within those particular mucosal surfaces.”
She adds that this latter process facilitates a local immune response. The antibody T- and B-cells now focus on that particular mucosal membrane. The immune system cells are in the right place where the pathogen enters, allowing for a more rapid and effective response to various viruses.
What about COVID-19?
Does the intranasal approach to vaccination potentially apply to the novel coronavirus COVID-19? Answers Dr. Iwasaki “Absolutely yes. We have a study that we’re working on publishing soon, where we are combining some of the mucosal strategies to elicit local immunity against SARS-CoV-2.”
A mucosal vaccine may be better against viral variants. The newer approach provides mucosal-level immunity. In addition, the IgA antibody is a dimer (meaning it has two identical components), yielding four binding sites instead of only two.
The antibody can bind to surfaces of the virus even after some mutations accumulate. It’s much more resistant to variations on the viral surface.
I wonder if we will see Dr. Iwasaki win a Nobel Prize someday; if she can create a universal flu vaccine or a universal vaccine against other respiratory virus types. Thank you for joining me to explore this promising approach to vaccination.
