Studies in mice and monkeys show that nasal vaccinations can shield the animals from the new coronavirus — and that such vaccinations might be more effective than an injected form of the same vaccine.
David Curiel and Michael Diamond at Washington University School of Medicine in St Louis, Missouri, and their colleagues created a candidate vaccine encoding the SARS-CoV-2 spike protein, which the virus uses to invade cells (A. O. Hassan et al. Cell http://doi.org/d63k; 2020). The researchers then gave the vaccine to bioengineered mice that had human receptors for the protein.
After being injected with the vaccine and then exposed to SARS-CoV-2, mice showed no infectious virus in their lungs — but their lungs did harbour small amounts of viral RNA. By contrast, mice that had the vaccine inserted up their noses before exposure had no measurable viral RNA in their lungs. This and other evidence suggests that the nasal vaccine entirely warded off infection, the authors say.
Ling Chen at the First Affiliated Hospital of Guangzhou Medical University in China and colleagues developed another vaccine encoding the spike protein (L. Feng et al. Nature Commun. 11, 4207; 2020). The researchers found that both nasal and injected forms of the vaccine protected rhesus macaques (Macaca mulatta) from infection. The authors say that a vaccine that can be given by nose might allow people to vaccinate themselves.