Coronavirus vaccine: Why are companies working on developing nasal vaccines? Are they better than injected ones?

Hyderabad-based Bharat Biotech, makers of the homegrown Covaxin was recently in news for striking a deal that would allow it to produce upto a billion doses of a nasal COVID-19 adenovirus vaccine in collaboration with Washington University School of Medicine in St Louis, Missouri.

While the vaccine is currently in phase I trial in the country, it is expected that expansive trials will also be held in centres across India. Bharat Biotech will also be handling large-scale production of the vaccine at its Hyderabad headquartered base.

According to Krishna Ella, Chairman and Managing Director, Bharat Biotech, the development of a nasal vaccine would help bridge the gap between demand and supply in a good manner. “We envision that we will scale this vaccine to one billion doses, translating to one billion individuals vaccinated receiving a single-dose regimen,”

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While medical groups race against time to develop a preventive vaccine against novel coronavirus, there's also a lot more promising research being done to make vaccines more workable and appealing to the 7.8 billion population- experimental nasal vaccines being one of them.

Nasal vaccines, which work by delivering a vaccine jab through the nose, are considered to be an easier deliverable than the traditional vaccine doses, which are injected onto the skin.

In times of an urgent pandemic, experts also say that nasal vaccines would be able to do the job in a better manner, without spiking production or administration costs.

Confused? Here is a detailed explainer on nasal vaccines, how they work and why they might be the one scientific approach we need to keep a close eye on.

Simply said, nasal vaccines inject a vaccine dose into the respiratory pathways, instead of the bloodstream capillaries. The dose is either injected through a special sleek nasal spray, liquid medicine dose or aerosol delivery.

While traditional vaccines target the host cell by taking a longer route, nasal vaccines are able to directly intercept the chemical pathways of the virus, since they target the virus present in the mucosal membranes and respiratory cells, which often act as the first entry points for a virus to attack the body.

Due to this form of application, a nasal COVID vaccine would also be able to prevent attack on the respiratory tract and lungs, which, if not controlled in time could lead to a rapid health decline.

Terming them to be a useful tool for launching a 'multi-pronged attack', experts have suggested that nasal vaccines would be able to target the deadly virus in a more careful and helpful manner by taking on an active role from the first level barriers of the body, i.e., the nasal cavities, respiratory tract and passageways.

There are also fewer chances of the body rejecting it. The drug, supplied through the nasal vaccine can be rapidly absorbed through the nasal mucosal linings since it is supplied by many blood vessels.

While all vaccines work to spike antibody levels and provide sufficient immunity, there's another reason as to why nasal vaccines might be slightly better than injectables.

Administration of an intranasal vaccine could ensure that the body is better protected against a virus. Since it directly interacts with the cells present alongside nasal tissues, it targets T-cells present in the linings. This would be able to provide systematic and mucosal immunity and lower the chances of infection spread. A lot of studies are also going on to confirm the same.

While vaccine development is in full swing right now, one of the biggest issues to tackle right now would be delivery and production. Lack of awareness, inadequate or patchy healthcare system could lead to problems with vaccine delivery. Right now, frontline workers will have to be taught or trained on how to deliver a vaccine. In comparison to this, nasal vaccines can be self-administered by people and could cut down on the need for medical consumables, such as needles and syringes.

Such a technology would ensure that vaccine delivery happens everywhere, in the remotest of the places. Clearing out such hindrances would also allow makers to scale up production, such as what Bharat Biotech aims to do.

Hence, the prospect of broader reach and easier administration do place nasal vaccines a bit ahead of other vaccines being worked on right now.

Bharat Biotech isn't the only company to work on developing a nasal vaccine. An intranasal spray being co-developed by Beijing Wantai Biological Pharmacy Enterprise with researchers from Xiamen University and Hong Kong University has already been granted emergency authorisation from authorities to be used on people.

Another nasal vaccine under consideration is being developed by scientists based out Australian university. Reports suggest that three other intranasal vaccine approaches are under consideration. However, nasal vaccines will take some time to develop and may not be the first one to reach us.