Nasal vaccine protects mice from various respiratory infections

Research from the US reports that a new nasal vaccine protected mice against a wide range of respiratory threats.   

Most vaccines train the immune system to recognise a specific target called an antigen, like small portions of a virus or bacteria. This can be problematic when viruses evolve quickly, or new pathogens emerge, changing the targeted antigens and rendering previous vaccines ineffective – normally the case with the flu vaccines.  

Stanford Medicine researchers developed a vaccine designed to keep lungs ready for infection and overcome the short-lived “immune burst”. Through nasal administration, researchers exposed the lungs of mice to the vaccine, leading to an immune response by T cells that recognise antigens.  

This vaccine – named GLA-3M-052-LS+OVA - includes an egg protein called OVA, a harmless antigen known to recruit immune responses, and an immune system stimulant (GLA-3M-052-LS), leading to an immune response without causing disease. 

With three doses given a week apart, vaccinated mice were protected against SARS-CoV-2 and other coronaviruses for at least three months. When infected with SARS-CoV-2, vaccinated animals lost less weight, improved survival, maintainedgreater immune readiness and had nearly clear lungs with reduced virus levels by 700-fold compared to unvaccinated mice.  

The researchers also tested the vaccine against two common hospital-acquired infections (S. aureus and A. baumannii) and dust mite particles responsible for allergic asthma, and reported similar disease protection.   

Bali Pulendran, from Stanford and senior author of the study published in Science said: “Imagine getting a nasal spray in the fall months that protects you from all respiratory viruses including COVID-19, influenza, respiratory syncytial virus and the common cold, as well as bacterial pneumonia and early spring allergen. (…) That would transform medical practice.”   

The researchers will now proceed with a Phase I safety clinical trial involving human participants.