Nasal Vaccines: What Are They?

The majority of us have been jabbed at least twice by now; a needle in the shoulder and sore arms for days afterwards. But needles, or intramuscular injections, are not the only method of vaccination. Nasal vaccines are emerging as a promising future for COVID boosters.

Bharat Biotech, a vaccine developer in India, is developing a nasal COVID vaccine. It’s recently received approval from India’s Drug Controller General to conduct Phase 3 trials. If successful, their spray could become the first nasal vaccine against Sars-CoV-2 in the world.

How do nasal vaccines work?

Intramuscular vaccines produce antibodies in the bloodstream, triggering powerful and long-lasting immunity. These antibodies are like soldiers in a fortress, protecting the host against severe illness once the castle has been compromised.

Nasal vaccines coat the mucus surfaces of the nose, mouth and throat with long-lasting antibodies. As these mucosal linings are the points of infection for COVID, antibodies from nasal vaccines can be seen as sentries guarding the fortress from ever being penetrated.

As we’ve seen, intramuscular vaccine immunity wanes. Two doses of our current vaccines are essentially ineffective against symptomatic Omicron. It’s almost certain at least some of us will need more boosters as new variants develop and our vaccine-triggered immunity declines.

Nasal vaccines can be a great alternative to injections for boosters, given they’re more time- and resource-efficient. In a surge, a nasal spray is quicker than a needle jab, and doesn’t require trained healthcare professionals to administer. Vaccinating nasally also avoids syringe shortages, unlike our current system.

Intramuscular vaccines have many associated concerns, including needle shortages and subsequent reuse.

They may also have an advantage in preventing virus spread. Current vaccines are designed to ease strain on hospital systems by preventing severe illness. But in a huge surge like Australia’s Omicron wave, this strategy starts to buckle.

By targeting the infection point of the virus, nasal vaccines are designed to stop the host from contracting the virus in the first place. Plus, it’s less painful than a needle, making booster shots for children and needle-phobes easier.

Nasal vaccines have already proven to protect against COVID in various animals, and Bharat Biotech’s trials are already underway on double-vaccinated Indians. A recent study by Yale scientists reported nasal vaccination “elicits a much more robust and cross reactive, cross protective immunity than a conventional vaccine that uses intramuscular injection.”

Intramuscular injections are still the most reliable way to build up long-term protection, but nasal vaccines are now emerging as a valuable alternative for booster doses.

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