Bharat Biotech's intranasal vaccine: What is it? How can it prevent COVID infection?

With Omicron variant cases on the rise, Covaxin manufacturer - Bharat Biotech (BBL) has come up with a new intranasal vaccine for the virus. They have submitted the phase III clinical trial data to the Drugs Controller General of India (DCGI) for approval to use its intranasal vaccine as a booster dose for the vaccinated population. 174 Omicron cases have been identified as of date in India.

What is BBV154?

BBL's intranasal vaccine (BB154) is essential for blocking both infection and transmission of COVID-19. The vaccine stimulates a broad immune response – neutralizing IgG, mucosal IgA, and T cell responses, states Bharat Biotech. The vaccine generated immune responses at the site of infection i.e. the nasal passage, stopping transmission and infection.

The vaccine also has other advantages like - non-invasive, needle-free, suitable for both children and adults and scalable manufacturing to produce on a global level. The animal protective studies showed that mice, hamsters and macaques showed viral clearance in both lower and upper airways of the nasal passage. The study is yet to be peer-reviewed.

The biggest difference between Covaxin and BBV154 is that the intranasal vaccine is based on an adenovirus vector, while as Covaxin used a Whole-Virion Inactivated Vero Cell - a dead virus. BBV154 uses the same virus vector as India's most used COVID vaccine - Covishield. The immune responses generated too is likely to reflect it.

In an interview with Republic TV, Dr.Krishna Ella (CMD -BBL) stated that the nasal vaccine will help to innoculate children. Detailing the functioning of a nasal vaccine and how it will be administered he said, "If you take one dose of nasal vaccine you could block the infection and thereby block the transmission chain and then you can flatten the curve. It is just about 4 drops like Polio, 2 in one nostril and 2 in the other. Now global authorities like the WHO are getting convinced about nasal as a second-generation vaccine. Injectible vaccines don't stop transmission. We can tie up globally on nasal vaccines," he remarked.

About Covaxin

Covaxin's phase-3 trials showed that the vaccine clocked an overall efficacy of 77.8%. Covaxin is 93.4% efficacious against severe symptomatic cases, 78% effective against mild and moderate cases and 63% effective on asymptomatic cases. The vaccine has also shown 65.2% efficacy against the Delta variant of COVID-19 with the vaccine being well tolerated with no clinically or statistically significant differences in serious adverse events. Covaxin has been tested on 25,800 volunteers across 25 trial sites on subjects ages 18-98 years - India's largest efficacy trial. Covaxin has also been granted emergency approval by WHO. Covaxin is supplied to Centre at Rs 215 and at Rs 1410 at private hospitals for a 2-dose regimen injected at 28 days' interval.