Hyderabad-based Bharat Biotech has received approval from the Indian Central Drugs Standard Control Organisation (CDSCO) to initiate clinical trials to assess the efficacy of its nasal vaccine BBV154 in healthy volunteers.
Unlike Covaxin which Bharat Biotech produced after inactivating a live virus, this nasal vaccine was created with the help of an adenoviral vector like Oxford university's Chad-Ox vaccine and Russia's Sputnik vaccine. This means that the researchers used the virus present in chimpanzees and mixed it with the spike protein of SARS-CoV-2.
This nasal vaccine is produced by Bharat Biotech in collaboration with American company Precision Virologics and the Washington University School of Medicine in St Louis, Missouri, United States.
Both the government of India as well as Bharat Biotech intend to use the nasal vaccine as a booster shot for those who received two shots of the vaccine and even as a potential vaccine for those under sixteen, as Covaxin is currently being administered to children between the ages of 15 to 17. However, for the booster dose, the vaccine manufacturer may face trouble finding 5000 healthy, unvaccinated individuals who have not been exposed to the virus.
Nasal vaccines are found to be more effective to act against respiratory ailments, according to a recent study conducted by scientists at Yale School of Medicine. Currently, only a vaccine acting against influenza is available in the form of nasal vaccines.
Along with Bharat Biotech, a Russian firm as well as the National Institute of Allergy and Infectious Diseases (NIAID) are researching and working on nasal vaccines.
How Do Nasal Vaccines Affect Respiratory Illnesses?
In a study published on December 10, scientists from Yale School of Medicine found that intranasal vaccines were more efficient against respiratory viruses primarily the influenza virus over injected vaccines. Conducted by Akiko Iwasaki from the Department of Immunobiology, the study found that the mucosal linings in the upper nasal pathway prevent the entry of the virus better than the protection provided by the intramuscular injections.
As the nose is the entry to the respiratory pathway, the mucosal linings are the first line of action. According to the researchers, this lining allows the first line of defense and immune response in the body along with the T cells and B cells that are the other immune defenses to start doing their own work.
In an interview on the website of Yale School of Medicine, Iwasaki mentioned that they are trying to emulate the same for SARS-CoV-2 and are working on a paper in that direction. The researchers have witnessed cross protective, long-lasting immunity within the respiratory mucosa.
It is also believed that nasal injections provide long-lasting immunity which could be for a longer duration than intramuscular vaccines.
Challenges With Testing Nasal Vaccines
Bharat Biotech's first results on animals and a few healthy individuals showed that the vaccine is safe and elicits immunogenicity, but to check whether it neutralises the virus to a large extent, large scale trials are required. For that reason, the CDSCO has approved the next stage of trials.
For clinical trials, Bharat Biotech requires 5000 healthy individuals to participate in the trials. However, over 96 per cent of the population in the country has already received one dose of the vaccine. They have antibodies against the virus. Furthermore over 4 crore people have been diagnosed with COVID-19 thus having natural immunity against the virus.
