- A single-dose intranasal ChAd vaccine protects upper and lower respiratory tracts against SARS-CoV-2, inducing high levels of neutralizing antibodies and virtually completely prevents COVID-19 infection in both the upper and lower respiratory tracts in mice. (Cell, PDF, 19 August 2020) https://www.cell.com/action/showpdf?pii=s0092-8674%2820%2931068-0 15 comments science