Inhaled COVID-19 Vaccines Could Potentially Be More Effective at Lowering Risk of Transmission

“Inhaled vaccines?” you scratch your head.

Yep! Apparently, other than getting injections, you could receive a vaccine via a nasal spray!

Inhaled COVID-19 Vaccines Could Potentially Be More Effective at Lowering Risk of Transmission

According to The Straits Times, inhaled or intranasal vaccines that are sprayed into the nose mimic the way respiratory viruses usually infect a person, by entering the respiratory tract.

This would’ve saved us from lots of screaming children…Well, not really. Unfortunately, there are no licenced nasally delivered vaccines in Singapore.

The intranasal vaccines are expected to induce a strong local immune response in the upper respiratory tract. That is where the Sars-CoV-2 virus takes hold.

Associate Professor Sylvie Alonso, co-director of the Infectious Diseases Translational Research Programme at the NUS Yong Loo Lin School of Medicine explains that the local immune response is “therefore potentially more effective at blocking the pathogen immediately when the virus is inhaled or comes into contact with the nose.”

As such, there will be a higher chance of lowering human-to-human transmission as the pathogen will be neutralised immediately or soon after it starts replicating.

China’s drug authority had approved of an inhaled vaccine co-developed by CanSino Biologics for clinical trial last week.

It no different in terms of virus species, cell banks, production technology or preparation formula from the injection-based COVID-19 vaccine, said Chinese state-owned newspaper Global Times. However, it has an atomisation inhalation device.

This device enables the vaccine to be atomised into tiny particles and then inhaled into the respiratory tract and lungs to stimulate an immune response in the mucous membranes, a Beijing-based immunology expert explained.

Pros and Cons

Such vaccines have the added benefit that trained personnel are not needed to administer them. This could help accelerate mass vaccination at a cheaper price, especially for lower- and middle-income countries.

However, Professor Ooi Eng Eong from the emerging infectious diseases programme at Duke-NUS Medical School cautioned that the theoretical benefits of intranasal and inhaled Covid-19 vaccines are uncertain without efficacy trials.

Prof Ooi pointed out that these vaccines are merely in the exploratory stages of testing and clinical trials will have to be carried out to show they are safe and to compare their efficacy with vaccines that have been approved.

In addition, as the nasal cavity is close to the brain, developers must ensure that components of the vaccine cannot reach the brain.

There are also difficulties in administering the vaccine such as the patient sneezing immediately after, thus affecting the dosage and efficacy of the vaccine.

Prof Alonso also notes that while vaccines administered orally, nasally or vaginally have been in development for decades, there needs to be increased support for their basic research.

Other Intranasal Vaccines

Oxford University announced last Thursday (25 Mar) that it will be launching a study of immune responses of a nasal administration of its vaccine developed with AstraZeneca.

In addition, local biotech firm Esco Aster is working with US company Vivaldi Biosciences to develop a vaccine that will be delivered as a nasal spray. This vaccine will be made by merging proteins from different viruses and is currently undergoing animal studies.

Featured Image: Josep Suria / Shutterstock.com