A team of scientists led by University of California (UCSF) graduate student Michael Schoof, engineered a completely synthetic, production-ready molecule that straitjackets the crucial SARS-CoV-2 machinery that allows the virus to infect our cells. They believe that the nasal spray can prevent humans from catching Covid-19 and could even be more effective than wearing PPE. As reported in a new paper, now available on the preprint server bioRxiv, experiments using live virus show that the molecule is among the most potent SARS-CoV-2 antivirals yet discovered.

In an aerosol formulation they tested, dubbed “AeroNabs” by the researchers, these molecules could be self-administered with a nasal spray or inhaler. Used once a day, AeroNabs could provide powerful, reliable protection against SARS-CoV-2 until a vaccine becomes available. The research team is in active discussions with commercial partners to ramp up manufacturing and clinical testing of AeroNabs. If these tests are successful, the scientists aim to make AeroNabs widely available as an inexpensive, over-the-counter medication to prevent and treat COVID-19.

Though engineered entirely in the lab, AeroNabs were inspired by nanobodies, antibody-like immune proteins that naturally occur in llamas, camels and related animals. Since their discovery in a Belgian lab in the late 1980s, the distinctive properties of nanobodies have intrigued scientists worldwide.

SARS-CoV-2 relies on its so-called spike proteins to infect cells. These spikes stud the surface of the virus and impart a crown-like appearance when viewed through an electron microscope – hence the name “coronavirus” for the viral family that includes SARS-CoV-2. Spikes, however, are more than a mere decoration – they are the essential key that allows the virus to enter our cells.

Lab tests have shown the tiny proteins — about a quarter of the size of antibodies found in humans  — can block the coronavirus from entering cells.    

But the AeroNabs formula still needs to be proven in clinical trials, to see whether it really can prevent a person from actually getting infected.