Nasal vaccines offer a new hope
Vaccination has emerged as an effective tool in preventing severe COVID-19 infections and reducing overall cases of hospitalisations. Currently vaccination is done through the traditional method of injecting the vaccine into the arm. However, nasal vaccines, which are currently under development, may hold the potential to prevent COVID-19 infection entirely, including the mild cases.
Scientists believe vaccines administered through the nose may be better suited to prevent the infection, compared to the shots administered intramuscularly. However, most nasal vaccines under development currently, will work like a booster dose.
How do traditional vaccines work?
Intramuscular administration of vaccines, which is the currently practiced traditional shot in the arm, provides you with systemic immunity. This involves building up of antibodies, which are distributed in different organs of the body. That is why these vaccines are effective in protecting against severe disease. However, with newer immunity-evading sub variants of Omicron, existing vaccines are failing to prevent reinfection and breakthrough infections.
On the other hand, nasal vaccines induce antibody production in the mucosal tissue — the inner lining of the nose, throat and mouth, from where the virus usually enters the body.
How do nasal vaccines work?
Nasal vaccines provide an immunity boost right where the virus enters the body. By concentrating the immunity in the upper airway, the antibodies can prevent the infection not just from affecting, but even entering your body in the first place, as these are right there on the front lines. Experts believe nasal vaccines could also help in prevention of long COVID and curb overall transmission of coronavirus.
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Benefits of intranasal vaccine
The nasal route has excellent potential for vaccination and protection against COVID-19. It is non-invasive, needle-free and can be easily administered. Administration of nasal vaccines may not even require trained health care workers. It is believed to be suitable and compliant for adults as well as children.
Nasal vaccines in development
Development of nasal vaccines is still a bit behind in the US. Researchers at Yale University are looking at two approaches of the nasal vaccine – a protein-based nasal spray and an mRNA vaccine delivered into the nose using nanoparticles. In both cases, the nasal vaccine is intended to build upon the existing immunity created through previous vaccination shots.
In India, research is further along. The clinical phase III trials of the Bharat Biotech COVID-19 nasal vaccine have been completed and if everything turns out okay, then it could be launched, making it the world's first clinically proven nasal COVID-19 vaccine.
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A long way to go
While the early findings are promising and the vaccines may aid complete elimination of the virus transmission, there is still time to know when they can be launched and if they will turn out to be truly successful.
Nasal vaccines may provide stronger immunity in preventing the virus from entering the body. However, these too are likely to have repeated administration like booster doses. This is not just because our immunity from vaccination wanes after some time, but also because the new variants are increasing the risk of dodging immunity generated from vaccines.