Safety and lower airway immunogenicity of two candidate Coronavirus Disease (COVID-19) vaccines administered to the respiratory tract

For a COVID-19 vaccine to have maximum impact, it should not only prevent severe infection but also limit the shedding of virus so that transmission is interrupted and pandemic spread is controlled. Experience with the influenza vaccine FluEnz (which is given as a nasal spray) has shown that intranasal vaccines can be effective for both outcomes. All COVID-19 vaccines currently being trialled are delivered by injection but it is known that directly stimulating immunity at the site of infection (i.e. the nose and lung) induces specialised protective responses that may more quickly and completely control infection. This study will test the two leading UK COVID-19 vaccines to show that they are safe, well-tolerated and capable of stimulating immune responses both in the blood and the lung when administered to the respiratory tract. Using standardised methods, we will directly compare immune responses in the blood, nose and lower airway between these two vaccines as well as with data from ongoing clinical trials of intramuscular vaccination. Thus, we will show the effect of different vaccine technologies as well as delivery method and provide the critical information required to begin further clinical trials to show the efficacy of this needle-free vaccination strategy.