Bharat Biotech awaits booster dose nod for intranasal vaccine iNCOVACC

Bharat Biotech’s intranasal vaccine iNCOVACC has got the Indian regulator’s approval, but there is still some way before one can actually take it.

With almost all the eligible population having taken at least a single shot of a Covid-19 vaccine, the company has no potential market for iNCOVACC as a primary two-dose regimen. The company is waiting for approval for administering the vaccine as a booster shot after Covishield and Covaxin.

Krishna Ella, chairman and managing director of Bharat Biotech, admitted there was hardly any demand. “Despite the lack of demand for Covid-19 vaccines, we continued product development in intra-nasal vaccines to ensure that we are well prepared with platform technologies for future infectious diseases.”

The company has done clinical trials for the vaccine used as a heterologous booster dose after Covishield and Covaxin — and has submitted the same to the Drugs Controller General of India (DCGI). Heterologous boosting refers to using a booster dose which is different from the vaccine used for primary dosing.

Bharat Biotech did not comment on its plans to make this vaccine available for young children. Being needle-free, this is likely to be popular among children below 12 years, which is also an untapped category at the moment.

Two separate and simultaneous clinical trials were conducted to evaluate the intranasal vaccine: as a primary dose (2-dose regimen), and a heterologous booster dose for subjects who had already received two doses of the two commonly administered Covid vaccines in India — Covishield and Covaxin.

The Hyderabad-based company has established large manufacturing capabilities at multiple sites across India — Gujarat, Karnataka, Maharashtra, and Telangana, the company said.

Experts, however, felt that it was not yet clear how many doses of the intranasal vaccine as a primary dosing would generate long-term immunity.

Jacob John, senior virologist and former head of the departments of clinical virology and microbiology at Christian Medical College (CMC), Vellore, told Business Standard that he was not sure if the intranasal vaccine by itself would be a good idea as a primary dosing for long-term immunity.

He said the reason why there’s a need for annual booster doses of the flu shot was to keep the antibody levels high for this highly mutating virus. “When we take an annual booster, then there are some spillover antibodies in the nasal mucosa, which may help to fight the virus. Flu has an incubation period of 1.5 days, and our immune system takes 5-6 days to mount an attack by launching antibodies,” John explains, adding that this Covid19 nasal vaccine too will be required to be taken periodically.

“We have to see what is the interval at which this would be required to be taken. It could be one year or two years or a gap of five years,” John said.

Meanwhile, intranasal or mucosal vaccines are the future of Covid-19 vaccination. Already 100 projects are in various stages of development across the world for mucosal (nose and mouth) vaccines. Around 20 of these projects have also reached the human trial phase. (see chart)

“Nasal vaccine works by suppressing the broad immune response of the virus in nasal cavity by neutralising IgG antibodies suppressing mucosal IgA antibodies and T cell response. By doing so it decreases the chances of spread of this infection to other people which is the major challenge and the major cause of the pandemic that has happened due to Covid-19 virus,” said Rahul Sharma, additional director (pulmonology), Fortis Hospital, Noida.