Will nasal vaccines offer maximum protection against Covid-19? What we know
Nasal vaccines, which are under trial across the world, are believed to be more effective than intramuscular vaccines as nasal vaccines are supposed to provide mucosal immunity in the nose -- one of the entry points of the SARS-CoV-2 virus. The current vaccines are intramuscular vaccines and that is why they do not guarantee that the virus will not enter the body. What they assure is that the disease will not become severe after vaccination. While the arrival of nasal vaccines is being seen as a landmark, a combination of an intramuscular vaccine and a nasal vaccine can be a gamechanger, experts believe.
The subject expert committee of the Central Drugs Standard Control Organisation has recommended a trial of combining Bharat Biotech's Covaxin and an intranasal vaccine where the subjects will be provided with the first shot of Covaxin and the second shot of a nasal vaccine.
There are seven intranasal Covid-19 vaccines under clinical trial across the world. Bharat Biotech is one of them. The other nasal vaccines under trial are by Oxford University, Altimmune, University of Hong Kong, Meissa Vaccines, Codagenix and Cuba's Centre for Genetic Engineering and Biotechnology.
Sharing a study of the intranasal vaccines under clinical trials, Bharat Biotech's Dr Raches Ella recently said that nasal vaccines may overcome the shortfalls in intramuscular vaccines. "Perhaps the ideal mode of protection (against disease and infection) might require IgA (mucosal) + IgG (systemic) + Memory B/T cells. If achieved, we may limit transmission," Dr Ella tweeted.
A nasal vaccine evokes all these three kinds of responses in the human body, while intramuscular vaccines can't stop the infection from entering the body.
Bharat Biotech founder Krishna Ella has said the company is expecting significant data about nasal vaccines in the next two and half months.
Why nasal vaccines can be the gamechanger
As vaccination is going on and cases of breakthrough infections are also being reported, it is now clear that intramuscular vaccines (all present vaccines in the world) prevent the severity of Covid-19. These vaccines do not guarantee future protection from infection and that's why vaccinated people are also supposed to adhere to Covid-appropriate behaviour. The nasal vaccine, as experts said, can actually block the infection from entering.