Inhaled COVID-19 Vaccine Protects Against Variants of Concern

Intranasal COVID-19 vaccines aren’t just needle and pain-free—they may also be more effective at protecting against current and future variants.

Needle injections are assuredly unpopular. Though the personal and public health benefits of inoculation are well documented, no one looks forward to getting a shot. Luckily, investigators from McMaster University have developed an intranasal COVID-19 vaccine that provides lasting protection against variants of concern.

The research, published in Cell, demonstrated that inhaled vaccines may even be more effective than a vaccine jab in protecting against COVID-19. Respiratory viruses target the lungs and upper airways first, so in addition to being needle and pain-free, an inhaled vaccine delivers an immune response where it’s needed most.

“What we’ve discovered from many years’ research is that the vaccine delivered into the lung induces all-around protective respiratory mucosal immunity, a property that the injected vaccine is lacking,” said Zhou Xing, a co-lead author of the study and a professor at the McMaster Immunology Research Center and Department of Medicine.

Xing previously developed a robust tuberculosis vaccine research program, upon which the inhaled COVID-19 vaccine strategy is based.

Xing and fellow investigators conducted a preclinical study in animals, and saw such positive results that a phase 1 clinical trial is currently underway in human participants. The trial evaluates the safety and efficacy of inhaled aerosol vaccines in healthy adults who already received 2 doses of a COVID-19 mRNA vaccine.

The investigators are comparing 2 types of adenovirus platforms for the vaccine, using SARS-CoV-2 viruses as vectors to safely deliver the vaccine directly to the lungs without causing illness.

The investigators stated that a primary objective was developing a vaccine that is effective against any current and future COVID-19 variants. All currently approved vaccines only target the spike protein, which has been proven to mutate extensively.

The McMaster vaccine is proven effective against highly transmissible variants, like Delta and Omicron, because it attacks 3 parts of the coronavirus, including 2 that are highly unlikely to mutate as rapidly as the spike protein.

Notably, the inhaled vaccine can provide maximum COVID-19 protection with just a fraction of the dose needed in injected vaccines. The researchers claim their intranasal vaccine requires as little as 1% of the current vaccine dosage to effectively target the lungs and upper airways, meaning vaccine doses could go much further and achieve widespread protection.

The intranasal COVID-19 vaccine may grant immunity against other respiratory vaccines as well: “We have revealed in our report that besides neutralizing antibodies and T cell immunity, the vaccine delivered into the lungs stimulates a unique form of immunity known as trained innate immunity, which is able to provide very broad protection against many lung pathogens besides SARS-CoV-2,” Xing said.