The UKRI and NIHR are now sponsoring a clinical trial exploring the effects of administering an inhalable COVID-19 vaccine as opposed to one by injection into the muscle similar to how inhaled asthma medications are taken. Led by Imperial College London and Oxford University, small trials will support investigations into the safety and efficacy of delivering the COVID-19 vaccine directly to the respiratory tract of human volunteers. A high powered collaboration involving Dr. Chris Chiu, the head of the Imperial Network for Vaccine Research, and Professor Robin Shattock, both with Imperial College London, alongside Professor Sarah Gilbert of Oxford is designed to modify existing vaccines for delivery via inhalable form.
The hypothesis here is that the direct targeting of cells lining the breathing airways are in fact a major place of infection associated with respiratory infections. The team hopes this can lead to more effective vaccines inducing a greater immune response. As stated by Dr. Chiu, “The current pandemic is caused by respiratory virus that primarily infects people through the cells lining the nose, throat and lungs.” He continued, “These surfaces are specialized and produce a different immune response to the rest of the body, so it is critical we explore whether the airways can provide an effective response compared to a vaccine injected into muscle.”
Led by Dr. Chiu at Imperial College London, the team will recruit a total of 30 participants for the trials. Imperial College London news reports that for each vaccine, researchers will assess three dose levels (low, medium and high dose) with three volunteers per group (18 in total), followed by an additional six in each group at the best dose (12 total). Volunteers will undergo bronchoscopy to obtain samples from deeper within the lungs while investigators also monitor the effects in the lower respiratory tract. This is, of course, in addition to blood and nasal sample analyses.
Additionally, the team will deliver the aerosolized vaccines via nebulizer, which delivers the vaccine as airborne droplets via a mouthpiece. The hypothesis: based on previous studies, a direct administration via respiratory tract can lead to lower dose requirements.
Other data points that the investigators will monitor include nasal samples for the presence of specialized antibodies existing in the nose and throat known as IgA, which indicate a more specialized and localized immune response to the virus. Of course, the team will analyze blood for the presence of neutralizing antibodies (immunoglobulin G, IgG) and T cells, virus fights that also protect against re-infection.
Chris Chiu, MD, Faculty of Medicine, Department of Infectious Disease
Professor Robin Shattock, Faculty of Medicine, Department of Infectious Disease
Professor Sarah Gilbert, Professor of Vaccinology, Jenner Institute, Nuffield Department of Clinical Medicine, University of Oxford