Promising Nasal Vaccine for COVID-19 Shows Strong Potential in Animal Studies

University of Maryland Researchers Develop Innovative Vaccine Delivery Method with Broader Applications

Recently, a team of researchers at the University of Maryland has developed a novel nasal spray vaccine that holds significant promise in the fight against COVID-19. This innovative vaccine delivers the SARS-CoV-2 spike protein directly into the airway cells of mice and hamsters, triggering an immune response that substantially reduces infection and the spread of the virus. Notably, this technology is adaptable and could be used to induce immunity against other respiratory illnesses, including influenza and respiratory syncytial virus (RSV) infections.

The study's findings, which mark a significant breakthrough in vaccine development, were published online on November 6, 2023, in the journal Nature Communications.

Unlike traditional intramuscular shots, a nasal vaccine for respiratory viruses offers several advantages. It is less invasive and acts to halt viral replication in the airway, preventing the virus from entering the bloodstream. This approach has the potential to improve vaccination rates and reduce the transmission of the disease.

Dr. Xiaoping Zhu, Professor of Veterinary Medicine at the University of Maryland and the lead author of the study, emphasized the importance of such a vaccine in the ongoing battle against COVID-19 and its evolving variants. He said, "We continue to hear about new variants, and new waves of COVID-19, and to prevent this, we need a vaccine that is easy to administer and can prevent transmission. This nasal vaccine prevents virus transmission and can be easily adapted for new variants."

SARS-CoV-2, the virus responsible for COVID-19, typically enters the body through the nose or mouth and replicates within the epithelial cells that line these passages. Traditional vaccines administered by injection primarily generate immunity in the bloodstream. This means the virus must first enter the bloodstream and replicate before it is detected by the immune system. In contrast, the new nasal vaccine creates immunity in the cells that line the nose, mouth, and throat, effectively blocking the virus's entry at its primary point of infection.

The key to this groundbreaking technology is a naturally occurring protein called neonatal Fc receptor (FcRn), which is responsible for transporting antibodies across epithelial cells. The researchers developed and patented a method to attach the SARS-CoV-2 spike protein to FcRn, which was then administered via nasal spray to mice.

In a series of experiments, mice were exposed to ancient SARS-CoV-2 as well as the Delta and Omicron variants of COVID-19. The results were remarkable. Unvaccinated mice exposed to the Delta variant experienced a high mortality rate, whereas a significant majority of vaccinated mice (ranging from 83% to 100%) survived. Even when exposed to major Omicron variants, the vaccinated mice exhibited reduced inflammation and lower virus loads compared to their unvaccinated counterparts.

Comparing the effectiveness of the nasal vaccine delivery method to traditional injections, the researchers found that the nasal vaccine induced a significantly stronger immune response in the airways and lungs. Most importantly, it substantially reduced the transmission of SARS-CoV-2 through the air. Given that inhalation is a major transmission route for COVID-19, this result is of paramount significance.

The development of this nasal vaccine comes at a crucial time, as new variants of COVID-19 continue to emerge, resulting in an increase in cases and hospitalizations. While existing mRNA vaccines remain effective at preventing severe illness and death, their ability to reduce infection and transmission over time may diminish. To address this challenge, the U.S. government's initiative, Project NextGen, aims to develop an effective and safe nasal vaccine to control the spread of variants. According to Dr. Zhu, the nasal vaccine developed by his team fulfills all the criteria outlined in Project NextGen's objectives.

This remarkable achievement represents a significant step forward in the ongoing fight against COVID-19 and respiratory illnesses, offering hope for a more effective and adaptable means of preventing disease transmission.

Vaccine Innovation Forum (VIF ) World 2024 will be held on Mar. 21-22, Shanghai China, which is the premier gathering for global vaccine scientists and leaders to discuss cutting-edge vaccine technologies, vaccine development progresses and partnership opportunities.