Bacterial induced IFN-y primes the lung for innate control of SARS-CoV-2 infection

In-person only

BCG is a 100 year old vaccine that while preventing disseminated TB in children has limited effects on adult pulmonary disease. Interestingly, in addition to inducing adaptive immunity against Mycobacterium tuberculosis, BCG vaccination has been demonstrated to display non-specific off target effects on tumor growth and is thought to reduce all-cause pediatric infections by promoting “trained immunity”. It was therefore proposed that intradermal BCG vaccination might provide resistance against COVID, a hypothesis that has not been epidemiologically substantiated. Nevertheless, we have observed that when administered to mice by the unconventional intravenous route BCG induces striking protection against intranasal SARS-CoV2. This non-specific resistance appears to result from priming of the lung epithelial compartment by T cell derived IFN-y. The broader implications of these findings for innate control of respiratory infections will be discussed.